Table of Content

01 March 2022, Volume 55 Issue 5

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CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Mapping of QTLs for Chlorophyll Content in Flag Leaves of Rice on High-Density Bin Map

ZHAO Ling, ZHANG Yong, WEI XiaoDong, LIANG WenHua, ZHAO ChunFang, ZHOU LiHui, YAO Shu, WANG CaiLin, ZHANG YaDong

Scientia Agricultura Sinica. 2022, 55(5):  825-836.  doi:10.3864/j.issn.0578-1752.2022.05.001

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【Objective】Finding new loci and genes related to rice chlorophyll content, and providing new theoretical basis for the research on the genetic mechanism of rice chlorophyll content. 【Method】 A recombinant inbred line (RIL) population containing 186 lines was constructed by crossing the japonica rice TD70 and the indica rice Kasalath with obvious difference in the chlorophyll content of the flag leaf. The two parents and RIL population were re-sequenced to construct a high-density genetic linkage map with 12 328 recombination Bin markers. The RILs and two parents were planted in fields at the Jiangsu Academy of Agricultural Sciences, in Nanjing in 2011 and 2020. The contents of chlorophyll of flag leaves were directly measured using the chlorophyll meter SPAD-502 on the 3^rd day after heading. QTLs that control the chlorophyll content of the flag leaf at the heading stage of rice were detected by IciMappingv3.4 software with inclusive compound interval mapping method. The photosynthesis parameters of 20 SPAD extreme strains in the RIL population were measured with a portable photosynthesis system. 【Result】19 QTLs controlling chlorophyll content of flag leaves were detected on 9 chromosomes except Chr.8, Chr.9 and Chr.10 in two years. The phenotype variation explained (PVE) of single QTL ranged from 3.09% to 13.13%, LOD value ranged from 2.74 to 14.08. After comparing the physical positions, 10 QTLs were found to locate in the same interval or adjacent to previously QTLs. qCHL2-1 and qCHL5-1 were detected every year showing their genetic stability. qCHL2-1 was mapped between the 7.63-7.71 Mb on chromosome 2, and the two-year LOD values are 14.08 and 7.93 with the PVE 13.13% and 7.94%, respectively. qCHL5-1 was mapped between the 23.44-23.49 Mb on chromosome 5, and the two-year LOD values are 4.31 and 3.76, respectively. After the annotation and sequences analysis of genes located in the region of qCHL2-1and qCHL5-1, two genes, Os02g0236000 and Os05g0476700, were found to be associated with chlorophyll content of flag leaves in the rice. There are differences in sequences of the two genes between TD70 and Kasalath. Os02g0236000 is the AAT1 gene encoding the Aspartate Aminotransferase, which is an important enzyme in nitrogen metabolism and related to protein and amino acid content of rice. Os05g0476700 encodes protein relating to spotted leaf, which might associate with leaf color. Based on the mutation of AAT1 at CDS+273 bp, the haplotypes of ATT1 were classified in RIL population. Among the 20 extreme SPAD RIL lines, there were significant differences between different haplotype of ATT1 in SPAD value, chlorophyll content, water use efficiency, transpiration rate, stomatal conductance and net photosynthetic rate of flag leaf. 【Conclusion】19 QTLs associated with chlorophyll content in flag leaf at heading stage of rice were detected and two stable QTL loci, qCHL2-1and qCHL5-1 were identified. Two candidate genes were obtained after annotation and sequence comparison. One of them, ATT1, was considered as the most possible candidate gene after effort analysis of different haplotypes in photosynthetic efficiency. The QTLs and gene we obtained could be used for subsequent functional studies of flag leaf chlorophyll regulation and molecular marker breeding.

Review and Prospect on the Breeding for the Resistance to Fusarium Head Blight in Wheat

MA HongXiang, WANG YongGang, GAO YuJiao, HE Yi, JIANG Peng, WU Lei, ZHANG Xu

Scientia Agricultura Sinica. 2022, 55(5):  837-855.  doi:10.3864/j.issn.0578-1752.2022.05.002

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Fusarium head blight (FHB) caused by Fusarium graminearum complex, is one of the most disastrous diseases seriously affecting yield and quality in wheat. Wheat kernels infected by Fusarium pathogen produce Fusarium mycotoxin, especially deoxynivalenol (DON), which may threaten the health of human beings and livestock. Breeding and application FHB resistant varieties is effective to control the disease and mycotoxin. Breeding for the resistance to FHB in wheat was commenced in 1950s in China. A national network on FHB research in wheat was established in 1970s. Inoculation methods were established and widely used for evaluating FHB resistance. Sumai 3, Wangshuibai and other resources with high resistance to FHB were selected and applied worldwide. Release of Yangmai 158 and Ningmai 9 with desirable agronomic traits and moderate resistance to FHB was a breakthrough in wheat breeding for FHB resistance. Such varieties have not only been widely applied in wheat production, but also produced more than 20 wheat varieties as parents of each variety. In addition to conventional breeding, chromosome engineering was used for transfer alien germplasm into wheat cultivated varieties, somaclonal variation and double haplotype produced by cell engineering techniques broadened genetic background and improved breeding efficiency in wheat genetic improvement for FHB resistance. The outbreak of FHB in North America in 1990s initiated the attention to FHB research in the United States and Europe. International cooperation prompted the exchange on material, technology and information in wheat breeding for FHB resistance. As results, significant progress in the research of FHB resistance type, inoculation techniques and evaluation index, germplasm development, QTL mapping, gene cloning, marker assisted selection and breeding for FHB resistance has been made. More than 600 QTL associated with FHB resistance were identified and located on all 21 chromosomes of wheat by using bi-parents linkage mapping and whole genome association analysis. Seven major genes/QTL were named as Fhb1-Fhb7. For the major QTL, Fhb1, associated with FHB resistance derived from Sumai 3 and Wangshuibai, the key candidate gene was cloned and validated, functional markers were developed and effectively used for marker assisted selection and new varieties possessing Fhb1 were released. The Fhb7 gene from Thinopyrum ponticum has also been isolated and used to improve FHB resistance in wheat. Pyramiding multiple QTL by marker assisted selection enhanced the resistance to FHB in wheat base on QTL fine mapping and close linked marker development. In the future, we should establish accurate phenotypic evaluation systems for evaluating the resistance to Fusarium head blight, strengthen the discovery of novel resistance germplasms and genes, isolate key genes related to FHB resistance and uncover their molecular mechanism, combine marker-assisted selection or genome selection with conventional breeding to continuously improve FHB resistance, breed wheat varieties with FHB resistance significantly improved and excellent agronomic traits.

Investigation on Important Target Traits and Breeding Potential of 120 Sweet and Waxy Maize Inbred Lines in the South of China

FENG XuanJun, PAN LiTeng, XIONG Hao, WANG QingJun, LI JingWei, ZHANG XueMei, HU ErLiang, LIN HaiJian, ZHENG HongJian, LU YanLi

Scientia Agricultura Sinica. 2022, 55(5):  856-873.  doi:10.3864/j.issn.0578-1752.2022.05.003

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【Objective】To investigate the agronomy, yield and quality traits of 120 sweet and waxy maize inbred lines, and analyze the correlation between different traits and evaluate the breeding potential by using candidate inbred lines. 【Method】 Investigating the general agronomic traits (flowering time, plant height, ear height), yield traits (fresh bud ear weight, fresh ear weight, fresh kernel weight, etc.) and quality traits (residue rate, brix, crude protein, crude starch, crude fat, etc.). The top 50% inbred lines with high yield and brix, and low residue rate were selected to determine the General Combining Ability (GCA) via diallel crossing. The same method was used to investigate the traits of the hybrid combinations, and the artificial score of taste was applied to six traits of smell, cheerful color, waxy/sweetness, flavor, tenderness and fineness, and the comprehensive score was obtained. The utilization value of the hybrid combinations was evaluated by comparing with the control varieties. 【Result】 The coefficients of variation of residue rate, yield, and sugar content of the tested inbred lines reached 20%, 30%, and 10%, respectively, implying there is a large genetic variation. The generalized heritability of most traits such as residue rate, yield and sugar content are above 50%, indicating that these traits have high genetic stability. In the sweet corn population, flowering time is negatively correlated with sugar content, and positively correlated with yield and residue rate. Yield is positively correlated with residue rate, but has no significant correlation with sugar content. These results suggested that it is not easy to have both good taste and high yield in sweet corn breeding, and that moderate early flowering materials will be better in field. In the waxy corn population, residue rate is negatively correlated with flowering time and yield traits, while the sugar content has no significant correlation with flowering time and yield traits. These results suggested that good taste and high yield can be achieved simultaneously in waxy maize breeding, and that moderate late flowering will be better in field. In the candidate sweet corn inbred lines, there are 3 lines have been identified to have positive GCA value for yield traits, brix, and negative GCA value for the residue rate, respectively. In the candidate waxy corn inbred lines, there are 3, 3, and 4 lines have been identified to have positive GCA value for yield traits, brix, and negative GCA value for the residue rate, respectively. Six sweet corn hybrid combinations and six waxy corn hybrid combinations with great comprehensive breeding potential have been isolated. Four black sweet corn hybrid combinations with application potential, and one inbred line SICAU76 with great application value in black grain have been isolated. 【Conclusion】The sweet and waxy corn inbred lines collected in this study have a large degree of genetic variation. The agronomic, yield, and quality traits of sweet and waxy corn have some intrinsic correlation. According to the correlation between flowering time and quality traits, moderate early flowering materials for sweet corn production, and moderate late flowering materials for waxy corn production will be better in field.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY

Effects of Crop Management Practices on Grain Quality of Superior and Inferior Spikelets of Super Rice

JIANG JingJing,ZHOU TianYang,WEI ChenHua,WU JiaNing,ZHANG Hao,LIU LiJun,WANG ZhiQin,GU JunFei,YANG JianChang

Scientia Agricultura Sinica. 2022, 55(5):  874-889.  doi:10.3864/j.issn.0578-1752.2022.05.004

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【Objective】The objective of the study was to explore the effects of crop management practices on grain quality including starch properties of superior and inferior spikelets of super rice, to provide the theoretical and practical guidance for improving rice quality, that is, the coordinated improvement of grain quality of superior and inferior spikelets. 【Method】The tested rice cultivars were super rice Y2640 and W24. There were four treatments in the field experiment, including zero nitrogen application (0N), local farmer practice (LFP), optimized cultivation 1 (T1) and optimized cultivation 2 (T2). For each treatment, there were three replicates. A split plot design was used in this experiment with crop management practices as the main plot, with variety as the split plot. In 2018, the appearance, processing, cooking and eating quality and RVA characteristics of rice were measured. In 2019, the experiments of scanning electron microscopy observation, crystallinity, infrared spectral distribution and RVA characteristics of superior and inferior grains of both varieties under different treatments were conducted. 【Result】 (1) For grain quality, compared with superior grains, inferior grains had better processing quality but worse appearance quality, protein content and hardness of inferior grains was increased, while amylose content, gel consistency viscosity and adhesiveness was decreased.(2) For starch quality, compared with superior grains, starch granules were smaller and the surface of starch granules were uneven and pitted in inferior grain, crystallinity and 1 045/1 022 cm^-1 value, setback, gelatinization temperature of inferior grains were increased, while peak viscosity, hot viscosity, breakdown, final viscosity of inferior grains were decreased.(3) Compared with LFP, by optimized crop management T1 and T2, the processing and appearance qualities of superior and inferior grains in both varieties were improved, protein content and amylose were decreased, while the gel consistency was increased, eating and cooking quality of superior and inferior grains were improved. The starch quality of superior and inferior grains were also improved, the relative intensity and order of structure were decreased, when compare crop management T1 and T2 with LFP. The grain and starch quality of inferior grains was more improved than superior ones by optimized crop management practices. 【Conclusion】The quality of rice and starch of inferior grains was significantly inferior to that of superior grains. Optimized crop management practices could improve grain yield and grain quality, especially for the grain quality of inferior grains.

Wheat Powdery Mildew Monitoring Based on Information Fusion of Multi-Spectral and Thermal Infrared Images Acquired with an Unmanned Aerial Vehicle

FENG ZiHeng,SONG Li,ZHANG ShaoHua,JING YuHang,DUAN JianZhao,HE Li,YIN Fei,FENG Wei

Scientia Agricultura Sinica. 2022, 55(5):  890-906.  doi:10.3864/j.issn.0578-1752.2022.05.005

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【Objective】Wheat growth and yield can be seriously affected by powdery mildew. Establishing the multi-source data fusion method for real-time monitoring of powdery mildew of wheat could provide technical support for accurate prevention and control of diseases and guaranteeing national food security. 【Method】During the wheat flowering and filling period, a six-rotor UAV equipped with multi-spectral sensor and thermal imager was used as a remote sensing data acquisition platform to obtain remote sensing images of different degrees of wheat powdery mildew. Then, vegetation index (VIs), texture feature (TFs) and temperature feature (T) were extracted from multi-spectral and thermal infrared images of different disease degrees on a low-altitude drone platform by ENVI software. Finally, the wheat powdery mildew disease index model were built by multiple linear regression (MLR), back propagation neural network (BP), random forest (RF) and extreme learning machine (ELM). 【Result】The precision of the RF model based on both single and multiple data sources was higher than that of the other models. Among the three data sources of the RF model, the vegetation indices (VIs-RF, R ²= 0.667, RMSE=5.712, RPD=1.572) were the most suitable for powdery mildew monitoring, followed by the temperature feature (T-RF, R ²= 0.559, RMSE=6.563, RPD=1.430) and texture features (TFs-RF, R ² = 0.495, RMSE=7.014, RPD=1.348). When combining multiple data sources, a precision for the RF model combining vegetation indices and texture features (VIs & TFs-RF) of 0.701 could be obtained, which was 5.101% higher than that of the VIs-RF model, while RMSE was 7.073% lower and RPD was 9.672% higher, whereas the precision parameters of the RF model combining vegetation indices and the temperature feature (VIs & T-RF) were R ² = 0.750, RMSE = 4.704, RPD = 1.912. For all three remote sensing data sources (VIs & TFs & T-RF), the following accuracies resulted: R ² = 0.820, RMSE = 4.677, RPD=1.996. As compared to the VIs-RF model, R ² improved by 12.453%, RMSE by 17.640% and RPD by 21.667% for the (VIs & T-RF) model, whereas for the three remote sensing sources, R ²improved by 23.181%, RMSE by 18.113% and RPD by 26.981%. At the same time, 10 fold cross validation of different models was carried out, which further confirmed that RF model had stable performance and good estimation results in multi-data source fusion modeling. 【Conclusion】 The precision of wheat powdery mildew monitoring could be improved by using multi-data-sources collaborative ML modeling. This research provided technical support for large-area and high-precision remote sensing of crop diseases.

PLANT PROTECTION

Spatiotemporal Dynamics and Source of Loxostege sticticalis in Northern China in 2020

CHEN ZhiYong, ZHANG Zhi, LIU Jie, KANG AiGuo, ZHAO SuMei, YIN XiangJie, LI ZhanQing, XIE AiTing, ZHANG YunHui

Scientia Agricultura Sinica. 2022, 55(5):  907-919.  doi:10.3864/j.issn.0578-1752.2022.05.006

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【Objective】To provide supports for improving the monitoring and warning level of the beet webworm, Loxostege sticticalis, the seasonal spatiotemporal distribution in Northern China, the sources and relationship between L. sticticalis in North and Northeast China, within and outside China were studied in 2020. 【Method】The searchlight traps were assembled to daily monitoring in Beijing, Tianjin, Hebei, Liaoning, Shanxi and Inner Mongolia. Based on the monitoring data of searchlight traps at the plant protection stations in the 6 provinces (municipality, Autonomous Region), the population fluctuations and migration pattern of L. sticticalis in Northern China were analyzed by using GrADS and R. The FNL data were processed by GrADS software, to obtain wind field information and draw the map. A three-dimensional particle trajectory analysis program based on WRF model was used to simulate the migration route of L. sticticalis, and the trajectory simulation results were plotted by ggplot2 3.3.0 package of R3.8. 【Result】The overwintering generation of L. sticticalis adults mainly occurred in Shanxi, Hebei and Inner Mongolia, and a large number of adults of the 1st generation were found in Huade of Inner Mongolia and Kangbao of Hebei in 2020. During the typical migration period, North China and Northeast China were affected by frontal and cyclonic processes. The southward or southwest low-level jet at the front of the northeast cyclone provided favorable conditions for the long-distance migration of L. sticticalis into the northeast region, but the northwest airflow at the back of it blocked the migration path. The results showed that most of the overwintering adults stayed in North China and some of them migrated to Northeast China and the border of China, Mongolia and Russia with the help of southwest airflow. In late May, the main source in Hinggan League of Inner Mongolia came from the overwintering area of L. sticticalis in North China. In early June, part of them came from the overwintering area of North China, part of them came from the junction of China, Mongolia and Russia. In late June, the main source came from North China. The adults of the 1st generation of L. sticticalis mainly came from the 1st generation larva occurrence areas in central and western Inner Mongolia and the border between China and Mongolia. Affected by the frontal weather, they gathered and landed in Huade of Inner Mongolia and Kangbao of Hebei, and further migrated to the northeast. 【Conclusion】2020 is a typical year of outbreak since the population of L. sticticalis has risen again in 2018. Strong air currents are important reasons for its successful migration, the convergence of wind shear and cyclone center causes the migrating adults to gather and land in large area, resulting in a sudden increase of local insect population. Both the overwintering generation and the 1st generation of L. sticticalis in North China and Northeast China were closely related to the foreign sources. It is of great significance to carry out the regional monitoring and prediction and forecasting in advance for L. sticticalis.

Preparation and Application of Indoxacarb Degrading Bacteria Immobilized Sodium Alginate Microspheres

WANG YuTai,XU ZhiFan,LIU Jie,ZHONG GuoHua

Scientia Agricultura Sinica. 2022, 55(5):  920-931.  doi:10.3864/j.issn.0578-1752.2022.05.007

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【Objective】The objective of this study is to prepare microsphere of degrading bacterium Pseudomonas stutzeri (ACCC 02521) with sodium alginate as carrier, and to establish the application conditions for degrading indoxacarb in farmland.【Method】Through the micro drop embedding ball forming method, bacteria were suspended and added into sodium alginate solution. After mixing, it was dropped into CaCl₂ for granulation. It was washed with 0.9% NaCl after fixing at low temperature. The mass transfer performance and mechanical strength of degrading bacteria microspheres were measured to determine the optimal concentration of sodium alginate. The best formulation was obtained by single factor optimization. 1.0%-5.0% CaCl₂, 40-200 g·L ^-1 bacteria or 20-100 g·L^-1preparation were dropped into 3.0% sodium alginate, respectively. The CaCl₂ concentration, embedded bacteria and preparation dosage in the degrading bacteria microspheres were determined according to the degradation rate of indoxacarb. The morphology of microspheres, cell morphology and distribution of degrading bacteria were observed by scanning electron microscope. Quantitative degrading bacteria microspheres were put into different types of soil suspension, temperature, pH or treatment time. The effects of environmental factors on the release capacity, degradation effect and stability of degrading bacteria microspheres were evaluated by calculating the amount of released bacteria (CFU/mL) or the degradation rate of indoxacarb. Two days after the routine application of pesticides, the degrading bacteria microsphere preparation was applied. Topsoil was collected to detect the residue of indoxacarb, the field application of dose was determined, and the field application conditions of the preparation were determined. The residual concentrations of indoxacarb were detected and tracked by HPLC.【Result】The preparation was composed of 3.0% sodium alginate, 2.0% CaCl₂ and 80 g·L^-1 degrading bacteria. The particle size was about 3.0 mm. The degrading bacteria microspheres had uniform particle size, moderate mechanical strength, good mass transfer performance, degradation activity and storage stability. Scanning electron microscopy showed that the degrading bacteria were evenly distributed in sodium alginate microspheres and their morphology was normal. In the soil with 10-30℃ and pH of 6.0-8.0, the degrading bacteria were released stably, and the degradation rate of indoxacarb was more than 85%. The release performance was not affected by soil type, the stability was good, and was less affected by environmental conditions. When 90-900 kg·hm^-2 of degrading bacteria microspheres were applied 2 d after field spraying of 150 g·L^-1 of EC active ingredient 20 mg·L^-1, the residual half-life (T_1/2) of indoxacarb in soil was shortened to 2.49-3.32 d (7.53 d for blank control area); furthermore when 450 kg·hm^-2 of degrading bacteria microspheres were applied 2 d after spraying indoxacarb with 5, 20 and 50 mg·L^-1, the values of T_1/2 was shortened from 6.03-7.45 d to 2.34-3.59 d.【Conclusion】The preparation of degrading bacteria P. stutzeri microspheres with sodium alginate as carrier has stable performance, can significantly degrade indoxacarb residues in farmland and shorten T_1/2 time, provides technical and product support for bioremediation of soil pesticide residue pollution, and has the potential for further optimization and application.

SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT

Critical Nitrogen Dilution Curve and Nitrogen Nutrition Diagnosis of Summer Maize Under Different Nitrogen and Phosphorus Application Rates

LIU Miao,LIU PengZhao,SHI ZuJiao,WANG XiaoLi,WANG Rui,LI Jun

Scientia Agricultura Sinica. 2022, 55(5):  932-947.  doi:10.3864/j.issn.0578-1752.2022.05.008

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【Objective】This study investigated the effects of different nitrogen and phosphorus application rates on summer maize aboveground biomass, nitrogen accumulation, and drew a critical nitrogen concentration dilution curve. The nitrogen status of maize plant was diagnosed and evaluated based on a model of nitrogen nutrition index (NNI) under different nitrogen and phosphorus interaction conditions, which provided a theoretical basis for the rational application of nitrogen and phosphorus fertilizers in summer maize.【Method】By using Zhengdan958 (ZD958) and Yuyu22 (YY22) as tested materials, the field experiments in Guanzhong Plain, Shaanxi included four phosphorus application rates and five nitrogen application rates, such as 0 (P0), 60 (P1), 120 (P2), 180 (P3) kg P₂O₅·hm^-2and 0 (N0), 75 (N1), 150 (N2), 225 (N3), 300 (N4) kg N·hm^-2during 2019-2020. The aboveground samples were taken during the jointing, tasseling, filling, and maturity stages of summer maize to analyze the effects of nitrogen and phosphorus application rate on maize dry matter accumulation, dynamic changes of nitrogen concentration and grain yield. The field test data was used to construct and verify the critical nitrogen dilution curve model of summer maize.【Result】The results showed that nitrogen and phosphorus application rate significantly increased aboveground biomass, plant nitrogen concentrations and grain yield of summer maize. The grain yield and aboveground biomass of summer maize increased as the nitrogen application rate increased within the same phosphorus application condition. The nitrogen concentration of maize plants showed a decreasing trend with the extension of growth period and the increase of aboveground dry matter weight. There was a power exponential relationship between nitrogen concentration and aboveground biomass. In addition, the phosphorus application could promote maize plant nitrogen absorption and aboveground dry matter accumulation. The overall performance of the phosphorus application treatments was P2>P3≈P1>P0 under the same nitrogen application conditions, appropriate phosphorus application could improve the capacity of maize plant for nitrogen absorption and relieved the decline of nitrogen concentration. The critical nitrogen concentration (N_c) curves of maize (P0, N_c=27.98DM^-0.249; P1, N_c=29.77DM ^-0.182; P2, N_c= 30.81DM ^-0.138; P3, N_c=30.06DM ^-0.187) were constructed according to the aboveground dry matter (DM) weight and its nitrogen concentration under different phosphorus application conditions; the relatively stable model had a linear correlation between the fitted and actual plant nitrogen concentrations, which showed that the n-RMSE were 10.23%, 6.67%, 6.95% and 7.19%, respectively. The NNI values were calculated based on the critical nitrogen concentration curves. NNI increased with the increase of nitrogen application in each growth stages within the same phosphorus application conditions, which was also positively correlated with relative aboveground biomass (RDW) and relative yield (RY). 【Conclusion】Based on the model of nitrogen nutrition(NNI) in this study, N2-N3 and P1-P2 were the best conditions. Based on the fitting curve of comprehensive nitrogen application rate and grain yield, the nitrogen rate of 187.5-205.7 kg·hm^-2and phosphorus rate of 60-120 kg·hm^-2was the optimal fertilization option for summer maize in Guanzhong Plain, Shaanxi.

Effect of Organic Fertilizer Replacing Chemical Fertilizers on Greenhouse Gas Emission Under the Conditions of Same Nitrogen Fertilizer Input in Maize Farmland

LI XiaoLi,HE TangQing,ZHANG ChenXi,TIAN MingHui,WU Mei,LI ChaoHai,YANG QingHua,ZHANG XueLin

Scientia Agricultura Sinica. 2022, 55(5):  948-961.  doi:10.3864/j.issn.0578-1752.2022.05.009

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【Objective】 The aim of this study was to investigate the effects of organic fertilizer replacing chemical fertilizer on soil greenhouse gas emission and global warming potential (GWP), so as to provide the theoretical basis for keeping crop yield stable, reducing fertilizer input and nitrogen (N) loss, and improving N use efficiency.【Method】In 2018 and 2019, a field experiment was conducted to study the effects of different organic fertilizers replacing chemical fertilizers rate on soil N₂O flux, CO₂ flux and GWP and carbon footprint by using static chamber and gas chromatography in maize yield. Four treatments, including control (CK), single application of inorganic fertilizer (NPK), organic fertilizer replacing 30% inorganic fertilizers (inorganic fertilizers 180 kg N·hm^-2+ organic fertilizer 90 kg N·hm^-2, NPKM30), and organic fertilizer replacing 50% inorganic fertilizers (inorganic fertilizers 135 kg N·hm^-2+organic fertilizer 135 kg N·hm^-2, NPKM50), were established during maize growth periods.【Result】There was no significant difference of maize grain yield among NPK, NPKM30 and NPKM50 in 2018 and 2019. During the maize growth periods, the N₂O emission flux showed temporal variations, and the average fluxes under three fertilizer treatments were higher than that under CK. Compared with NPK, NPKM30 increased the N₂O cumulative emission by 5.22%, while reduced by 7.92% for NPKM50 treatment. The N₂O cumulative emission over the maize growth periods accounted for 12.91? -18.74? of soil total N. During the maize growth periods, soil CO₂ flux showed similar temporal patterns among the four treatments, and the average flux for the two years ranged from 74.53 to 367.04 mg·m^-2·h^-1. Fertilization input significantly increased the cumulative CO₂ emission, and the average CO₂ accumulation under NPKM30 and NPKM50 treatments increased by 0.91% and 5.79% than that under NPK treatment, respectively. The average GWP under NPKM30 and NPKM50 treatments was 2.07% and 2.10% higher than that under NPK treatment, respectively. Compared with the NPK treatment, the GHGI and carbon emissions from per unit yield under NPKM30 treatment decreased by 2.46% and 1.43%, respectively, and increased by 3.37% and 1.43% under NPKM50 treatment, respectively. 【Conclusion】 Suitable organic fertilizer rate replacing some chemical fertilizer could keep maize yield stable, increase greenhouse gas emission and global warming potential, while reduce greenhouse gas emission intensity and carbon emissions from per unit yield. Considering the ecological benefits of maize production and greenhouse gas emissions, the organic fertilizer replacing 30% inorganic fertilizers would be a more ideal proportion of organic fertilizer to replace chemical fertilizer.

Inputs and Ecological Environment Risks Assessment of Maize Production in Northwest China

QIAO Yuan,YANG Huan,LUO JinLin,WANG SiXian,LIANG LanYue,CHEN XinPing,ZHANG WuShuai

Scientia Agricultura Sinica. 2022, 55(5):  962-976.  doi:10.3864/j.issn.0578-1752.2022.05.010

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【Objective】Make clear the input and ecological environment risk of maize production in Northwest China. 【Method】Based on the life cycle assessment (LCA) method, the inputs (fertilizer, pesticide, diesel, mulch, seed, and labor) and ecological environment risks (greenhouse gas emissions, soil acidification, water eutrophication and human toxicity) of maize production in six provinces (Xinjiang, Shaanxi, Shanxi, Ningxia, Inner Mongolia, Gansu) of Northwest China during the past 15 years (2004-2018) were evaluated, and the inputs, ecological environmental risks and spatiotemporal variations of maize production per unit area (per hectare) in those resources were quantitatively evaluated. 【Result】 Inputs and ecological environment risks of maize production were high in Northwest China. The average fertilizer input in past 15 years was 233.1 kg N·hm^-2, 106.3 kg P₂O₅·hm^-2, 23.3 kg K₂O·hm^-2, while the pesticide, diesel, mulch, seed and labor inputs were 6.5 kg·hm^-2, 93.2 L·hm^-2, 13.7 kg·hm^-2, 38.8 kg·hm^-2 and 120.1 h·hm^-2, respectively. The average maize yield was 7.9 t·hm^-2. The averaged greenhouse gas emissions was 4 188 kg CO₂-eq·hm^-2, the soil acidification potential was 155.3 kg SO₂-eq·hm^-2, the water eutrophication 52.6 kg PO₄-eq·hm^-2, and the human toxicity was 2.9 kg 1, 4-DCB-eq·hm^-2. Compared with the data in 2004, the overall input for maize production of Northwest China in 2018 was increased, showing an overall increased trend. The rates of nitrogen fertilizer, phosphorus fertilizer and potassium fertilizer per unit area increased by 9.2%, 52.7% and 203.7%, respectively; the rate of pesticide, diesel oil and mulch per unit area increased by 303%, 143% and 108%, respectively. The rates of seed and labor per unit area decreased by 38.6% and 50.8%, respectively, while the planting area and maize yield increased by 79% and 26.9%, respectively. On the whole, the multiple ecological environment risks showed a first increased and then decreased trend, in which the greenhouse gas emissions, soil acidification potential, water eutrophication potential and human toxicity per unit area increased by 13.6%, 15.8%, 2.6% and 302.5%, respectively. Among the 15 years of maize production in Northwest China, the highest nitrogen fertilizer input and greenhouse gas emissions per unit area were observed in 2016, and the lowest were observed in 2007. The inputs and ecological environment risks of maize production in different provinces of Northwest China were significantly different. In terms of unit area, the rate of nitrogen fertilizer, mulch and labor input was the highest in Gansu, and the lowest in Shanxi, Shaanxi and Inner Mongolia, respectively. The rate of phosphorus fertilizer and diesel was the highest in Xinjiang, and the lowest was Shaanxi. The rate of potassium fertilizer was the highest in Shanxi and the lowest in Xinjiang. The rate of pesticides and seeds was the highest in Ningxia and Xinjiang, and the lowest in Shanxi. The planting area and maize grain yield were the highest in Inner Mongolia and Xinjiang, and the lowest in Ningxia and Shaanxi, respectively. Simultaneously, the greenhouse gas emission and soil acidification potential were the highest in Gansu, the water eutrophication potential was the highest in Shaanxi, and the human toxicity was the highest in Ningxia and the lowest in Shanxi. The comprehensive value of inputs and ecological environment risks for maize production in Northwest China was the highest in Ningxia. Shanxi achieved the lowest comprehensive value of ecological environment risks for maize production in Northwest China. 【Conclusion】The maize production in Northwest China was characterized by “high input, high yield and high risk”, while the inputs and ecological environment risk were quite different in different spatiotemporal scale. From 2004 to 2018, the planting area, grain yield, and inputs were totally increased slightly, while the ecological environment risk showed a first increased and then decreased trend. The maize production could be considered to incline to high-yield and low-environmental risk areas, and achieve high yields and low ecological environment risks in the future.

HORTICULTURE

eQTL Analysis of Key Monoterpene Biosynthesis Genes in Table Grape

WANG HuiLing, YAN AiLing, SUN Lei, ZHANG GuoJun, WANG XiaoYue, REN JianCheng, XU HaiYing

Scientia Agricultura Sinica. 2022, 55(5):  977-990.  doi:10.3864/j.issn.0578-1752.2022.05.011

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【Objective】The eQTL mapping for monoterpene biosynthesis related gene expression traits were performed and the candidate genes were mined to deeply understand the regulation mechanism of monoterpene synthesis, so as to lay a foundation for the cultivation of new Muscat grape varieties and germplasm improvement.【Method】The F₁ population generated by crossing Moldova and Ruiduxiangyu were used as materials in this study, and the grape berry samples were collected at verasion and ripening stage respectively. The phenotypic data of expression traits were obtained by detecting the expression levels of seven monoterpene synthesis pathway genes (VvDXS1, VvDXS3, VvDXR, VvHDR, VvLiner, VvTerp, and VvGermD) by using real-time quantitative qPCR technique. eQTL mapping of monoterpene gene expression traits were performed with the mapQTL6.0 software based on the interval mapping method. The associated markers of eQTL were mapped to the genomic region, and the genes within eQTLs were annotated and analyzed via the databases of Ensembl Plants and NCBI. The expression profiles of candidate genes in the samples of parents at different developmental stages were detected by grape whole genome microarray.【Result】The expression levels of seven monoterpene biosynthesis related genes in F₁ population showed a continuous quantitative genetic distribution. A significant correlation between the expression of monoterpene genes was observed. At verasion, 13 eQTLs for the seven expression traits were mapped on chromosome 1, 6, 14, 16, 17, 10 and 12, respectively, and the phenotypic explanation value ranged from 12.2% to 23.5%. Among them, eQTLs (qDXS1-v14, qHDR-v14-1 and qTerp-v14) on chromosome 14 covered the same genetic interval of 57.582-76.979 cM, and qLiner-v10, qTerp-v10 and qGermD-v10 were co-located on chromosome 10. At the mature stage, 16 eQTLs were detected, mainly located on chromosome 1, 6, 12, 8, 13 and 19. qDXS1-m6-2, qDXR-m6-2, qLiner-m6 and qGermD-m6 were co-located in the genetic interval 139.212-143.161 cM of chromosome 6. In addition, a total of 18 eQTLs on chromosomes 1, 3, 7, 10, 12, 15 and 19 were detected for the change ratio of each gene expression between maturity and verasion, respectively. qDXS1-r12-1, qDXR-r12-1, qHDR-r12, qLiner-r12 and qGermD-r12 covered the same genetic interval of 6.330-6.967cM on chromosome 12. The eQTL region for multiple expression traits co-located were further annotated, 90 transcription factor genes were screened, and 11 candidate genes were finally identified by expression profile and correlation analysis. Among them, four candidate genes of VIT_06s0009g01380, VIT_14s0006g02290, VIT_12s0028g01170 and VIT_15s0046g00290 were predicted to participate in the regulation of hormone signaling pathway, one candidate gene VIT_12s0028g01110 encodes a phytochrome interacting factor related to light response, and some other genes encode Myb, WRKY transcription factors or unknown functional proteins.【Conclusion】A total of 37 eQTLs linked to monoterpene synthesis gene expression traits were detected at two different development stages, which mainly located on chromosome 6, 12 and 14. Based on the results of gene annotation and expression profile analysis, 11 candidate genes including VIT_14s0006g02290 and VIT_06s0009g01380 were identified, and these candidate genes were highly correlated with the expression of multiple monoterpene genes.

Diversity Analysis of 36 Leaf Phenotypic Traits of Chinese Chestnut

GUO Yan, ZHANG ShuHang, LI Ying, ZHANG XinFang, WANG GuangPeng

Scientia Agricultura Sinica. 2022, 55(5):  991-1009.  doi:10.3864/j.issn.0578-1752.2022.05.012

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【Objective】The objective of this study was to reveal the variation patterns and diversity characteristics of leaf phenotypic traits of Chinese chestnut, so as to provide the scientific basis for the protection, development and utilization of Chinese chestnut resources.【Method】Thirty-six leaf phenotypic traits (including 31 quantitative traits and 5 quality traits) of 240 Chinese chestnut germplasms from 10 provinces (populations) were measured. Variance analysis, multi-comparison, correlation analysis, and cluster analysis were used to explore the phenotypic diversity of chestnut leaf and the correlation between leaf phenotypic traits and climate factors.【Result】There were extremely significant differences (P<0.01) in 31 leaf quantitative traits within the population, and there were significant or extremely significant differences in 15 quantitative traits (leaf length, leaf width, leaf length/width, sawtooth height, etc) and 3 quality traits (leaf shape, shape of leaf base, and leaf margin sawtooth direction) among populations, indicating the abundant variation among and within populations. The average of phenotypic differentiation coefficient among populations was 7.95%, which was much less than that within populations (92.05%), illustrating that the variation within populations was the main source of leaf phenotypic variation. The average variation coefficient (CV) and the Shannon-Wiener index (H′) of leaf phenotypic traits were 18.05% and 1.27, respectively. Among the five quality traits, the CV and H' of leaf shape were the highest (35.67%, 0.86), the CV and H ' of leaf margin character were the lowest (5.60%, 0.07). The CV of 31 quantitative traits ranged from 8.68% (leaf length/width) to 32.73% (sawtooth depth), and the H′ ranged from 1.54 (fuzz density on the back of leaf) to 2.09 (looseness of leaf tissue). The average H′ of appearance, physiological and anatomical structure were 2.03, 2.04 and 2.04, respectively, and the average CV from high to low was 15.27% (appearance) >15.18% (physiological) >12.17% (anatomical structure). The average CV of leaf phenotypic traits in 10 populations ranged from 17.11% (Shaanxi) to 19.66% (Shandong), and the average H' in 10 populations ranged from 0.99 (Anhui) to 1.80 (Hebei). Most of the 36 leaf phenotypic traits of chestnut were significant or extremely significant correlated with geographical and ecological factors. The temperature indexes, such as annual mean temperature and average annual rainfall, were negatively correlated with leaf base shape, sawtooth height and other traits (longitude and latitude were positively correlated with them), and were positively correlated with leaf length/width (longitude and latitude were negatively correlated with them). 【Conclusion】There were abundant variations in leaf phenotypic traits among and within populations, but the variation within populations was the main source of chestnut leaf phenotypic variation. Therefore, the research should focus on a wide range of surveys of individual genotypes, and the populations with relatively rich and uniform variation could be used as the key reference areas when the phenotypic traits of leaf were taken as the research object for breeding varieties with stress resistance and high photosynthetic efficiency or the related research. Most of the appearance and physiological characters of chestnut leafs showed gradient regularity dominated by temperature and rainfall factors.

FOOD SCIENCE AND ENGINEERING

Effects of Starch Granule Size on the Physical and Chemical Properties of Barley Starches

XIAO LuTing,LI XiuHong,LIU LiJun,YE FaYin,ZHAO GuoHua

Scientia Agricultura Sinica. 2022, 55(5):  1010-1024.  doi:10.3864/j.issn.0578-1752.2022.05.013

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【Objective】 Barley, an important source of cereal raw material, is widely used in beer brewing, livestock feeding, and medicine and food healthcare, etc. Empirical evidences have showed that the granule size, composition and structure of starch in barley grain mainly determine its use. The present research was carried out to analyze the composition, structure and physicochemical properties of starch granules with different sizes from different barley varieties, which could help enhancing the utilization of barley starch from barley processing industries. 【Method】The starch from selected barley varieties, Xiyin-2, Jingxin-1 and Supi-6, was extracted and fractionated into large, medium and small-sized fractions by using differential sedimentation methods. The effects of granular size on micromorphology, crystal structure, apparent amylose content, amylopectin side chain distribution, thermal properties, hydration properties, gelatinization properties, and digestibility properties of barley starch was investigated.【Result】 The large-sized granules were mostly discal shape, while the medium-sized granules were oblate or oval spherical shape, and the small-sized granules were spherical or polygonal shape. All barley starch granules had a typical polarized cross under a polarized light microscope, and the polarized light spots enhanced as the granule size increased. The large-sized fraction had the highest percentages (87.62%-89.48%) in barley starch, followed by medium-sized fraction (8.97%-9.42%) and small-sized fraction (1.55%-3.29%). The apparent amylose content of barley starch ranged from 19.12 to 30.63 g/100 g. The effect of granule size on its content was not regular. All the samples were A-type crystals, and the relative crystallinity augmented with the increase of granule size. The side chain distribution of barley amylopectin presented a bimodal pattern, with the main peak at DP 12 and the secondary peak at DP 38. The highest content of amylopectin in barley starch was B₁ chain (34.34%-44.76%), followed by A chain (25.12%-34.52%). The average chain length of barley amylopectin was DP 22.86-25.00. The thermal characteristics of starch from barley varieties demonstrated that the gelatinization temperature range (∆T) of small-sized granules was the largest, and the gelatinization enthalpy (∆H) increased as the granule size increased. The swelling power of barley starch showed differences in varieties. All granule fractions of Jingxin-1 barley starch had higher swelling power. The results of pasting properties suggested that the small-sized granules had higher peak viscosity, breakdown and final viscosity of than the medium and small-sized granules. The results of digestibility characteristics showed that the rapidly digestible starch content of barley starch increased with the decrease of granule size, but the influence of granule size on its slowly digestible starch and resistant starch contents was not regular.【Conclusion】The granule size had a great influence on the structural characteristics of barley starch, such as the amylose content, the fine structure of amylopectin, and the relative crystallinity, thereby affecting the thermal properties, pasting properties, and digestibility characteristics of barley starch. The application characteristics of barley starch with different granule sizes were worthy of in-depth study.

ANIMAL SCIENCE·VETERINARY SCIENCE·RESOURCE INSECT

Effects of Cross-Ventilation System on Physiology and Production Performance of Beef Cattle in Summer

FANG HaoYuan, YANG Liang, WANG HongZhuang, CAO JinCheng, REN WanPing, WEI ShengJuan, YAN PeiShi

Scientia Agricultura Sinica. 2022, 55(5):  1025-1036.  doi:10.3864/j.issn.0578-1752.2022.05.014

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【Objective】 This study was conducted to explore the effects of cross-ventilation system on cowshed thermal environment, physiological and biochemical indexes, and production performance of beef cattle under the high temperature and humidity climate in summer of southern China, to evaluate the technical and economic effects of the environment control system for beef cattle heatstroke prevention. 【Method】 One-factor completely randomized design was introduced in this study. Thirty healthy 8-month-old Simmental bulls with similar body weight ((290.05±7.60)kg) were randomly assigned into two adjacent sheds with the same structure. The experimental group was equipped with the cross-ventilation system, and natural ventilation was used in the control group. The experimental period was from June 30 to July 16, 2019, a total of 17 days, in which the pre-test period was the first 3 days, and the formal period was the last 14 days. The wind speed, dry-bulb temperature and wet-bulb temperature were measured at 5:00, 10:00, 14:00, 18:00 and 22:00 every day in the first 7 days of the formal test period. The temperature-humidity index and sensible temperature were calculated. Meanwhile, the rectal temperature and respiratory rate of beef cattle were measured. During the whole formal period, the feeding amount was recorded every day, and the remaining materials were cleaned and weighed at 6 a.m of the next day to calculate the feed intake. From 7:00 to 8:00 in the morning on the first day and the fourteenth day of the formal test period, all cattle were weighed before feeding to calculate the average daily gain, feed weight ratio and other production performance indicators, and the economic benefit was evaluated. Simultaneously, the blood and fecal samples were collected for determination of inorganic ions, biochemical indexes and hormone levels in serum and cortisol levels in feces. 【Result】 The results showed that: (1) in the experimental group, the cross-ventilation system could significantly increase the wind speed in the shed (P < 0.01), thus significantly reduced the sensible temperature, the rectal temperature at 10:00, 14:00, 18:00, 22:00, and the respiratory rate of beef cattle at 10:00, 14:00, 18:00 (P < 0.01). Compared with the control group, with the increase of ambient temperature, the increase of rectal temperature and respiratory rate in the experimental group decreased by 45% and 42%, respectively. There was no significant difference in dry-bulb temperature, relative humidity and temperature-humidity index between the experimental group and the control group (P > 0.05). (2) At the end of the experiment, the serum calcium content in the experimental group was significantly lower than that in the control group (P < 0.05), while no difference was found concerning the contents of potassium ion, sodium ion, magnesium ion and chloride ion (P > 0.05). The results of serum biochemical indexes showed that the contents of heat stress protein 70, total protein, triglyceride and glucose in bovine of the experimental group were significantly higher than those in the control group (P < 0.05), and no significant difference was observed for the contents of serum albumin, globulin and total cholesterol (P > 0.05). The results of hormone levels showed that the levels of cortisol in feces and serum of the cattle in experimental group were significantly lower than those in control group (P < 0.05), and triiodothyronine and thyroxine had no significant difference in cattle between the experimental group and the control group (P > 0.05). (3) The production performance test showed that there was no significant difference in initial body weight and end body weight between the experimental group and the control group (P > 0.05), while the average daily gain (P < 0.01) and average dry matter intake (P < 0.05) of the experimental group were significantly higher than those of the control group, the feed-to-weight ratio of the experimental group was significantly lower than that of the control group (P < 0.05), and the profit in the experimental group was increased by 10.68%. 【Conclusion】 The cross-ventilation system could significantly increase the air velocity of the shed, reduce the sensible temperature, improve the metabolism of Simmental cattle, promote the production performance, and increase the economic benefits for beef cattle production in high temperature and humidity environment.

Effects of Additives on the Fermentation Quality of Agricultural By-Products and Wheat Straw Mixed Silage

ZONG Cheng, WU JinXin, ZHU JiuGang, DONG ZhiHao, LI JunFeng, SHAO Tao, LIU QinHua

Scientia Agricultura Sinica. 2022, 55(5):  1037-1046.  doi:10.3864/j.issn.0578-1752.2022.05.015

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【Objective】With the continuous development of food industry and processing industry, a large number of agricultural by-products were produced, including watermelon rind, broad bean pod and beer lees, which caused serious environmental pollution. In order to improve the feeding degree of agricultural by-products and wheat straw and to reduce environmental pressure, in this study, the effects of additives on the fermentation quality of agricultural by-products (watermelon rind, broad bean pod and beer lees) mixed with wheat straw were investigated.【Method】The mixture of agricultural by-products (watermelon rind﹕broad bean pod﹕beer lees = 1﹕3﹕4) and wheat straw, as raw materials, were mixed in ratios at fresh weight of 100%﹕0 (MW), 25%﹕75% (X25), 50%﹕50% (X50) and 25%﹕75% (X75), and the mixed silages were treated with additives: 1×10⁶ cfu•g^-1Lactobacillus buchneri (B), 0.2% FW cellulase (C), and 1×10⁶ cfu•g^-1Lactobacillus rhamnosus (R), and without additives (CON) as the control. The 200 g of raw materials treated with different additives were put into 250 mL polyethylene plastic bottles. After ensiling for 60 days at room temperature, the silos were opened to analyze the fermentation quality and nutrient composition. The treated silages and raw materials were filtered by two layers of gauze and qualitative filter paper, and the extract was used for measuring the pH value. The raw materials and silage were dried to a constant weight and the dry matter (DM) was measured. The crude protein (CP) was determined by Kjeldahl nitrogen determination method. The contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined by the method of Van’s fiber determination. The water-soluble carbohydrates (WSC) content was determined via the modified phenol-sulfuric acid method. The microorganisms were cultured and counted in the culture medium respectively. The organic acids were analyzed using high performance liquid chromatography. The ammonia nitrogen (NH₃-N) content was determined by the phenol-hypochlorite reaction method. 【Result】 Compared with MW-treated silage, NH₃-N content was notably decreased in X25-treated silage (P<0.05); pH and NH₃-N content were decreased in X50-treated silage, significantly (P<0.05); pH and NH₃-N content were notably decreased and the ratio of lactic acid to acetic acid (LA/AA) was notably increased in X75-treated silage, respectively (P<0.05). In addition, compared with the MW-treated silage, the butyric acid content was reduced in X25-, X50- and X75-treated silage, notably (P<0.05). In MW-treated silage, compared with the control, adding C significantly decreased the pH and NH₃-N content (P<0.05), and increased the lactic acid (LA) content and LA/AA (P<0.05). In X25-treated silage, compared with the control, adding C decreased the pH and increased the LA content, significantly (P<0.05); adding B decreased the NH₃-N content, notably (P<0.05). In X75-treated silage, compared with the control, adding C decreased the pH and increased the lactic acid content, significantly (P<0.05). As the increase of wheat straw mixing ratio, the contents of DM, NDF and ADF was increased, significantly (P<0.05). In contrast, the CP content was decreased, significantly (P<0.05). Compared with MW-treated silage, X25-, X50- and X75-treated silage increased WSC content, notably (P<0.05). In X25-treated silage, compared with the control, the addition of C significantly reduced the contents of NDF and ADF (P<0.05). In X50-treated silage, the addition of B and C significantly reduced the NDF content (P<0.05). In X75-treated silage, compared with the control, the addition of B, C and R reduced the contents of NDF and ADF, notably (P<0.05). 【Conclusion】The fermentation quality of mixed agricultural by-products (watermelon skin﹕broad bean pod﹕beer bad = 1﹕3﹕4) was poor. The mixed silage of agricultural by-products and wheat straw could improve the fermentation quality, and the best mixture ratios of wheat straw and agricultural by-products (watermelon rind﹕broad bean pod﹕beer lees = 1﹕3﹕4) were 50%﹕50% and 75%﹕25%. In terms of nutrition quality, X25 and X50 were the best mixture ratios of wheat straw and agricultural by-products (watermelon rind﹕broad bean pod﹕beer lees = 1﹕3﹕4) were 25%﹕75% and 50%﹕50%. Comprehensively considered the fermentation quality and nutritive value, the optimum mixing ratio of agricultural by-products (watermelon rind﹕broad bean pod﹕beer lees = 1﹕3﹕4) and wheat straw was 50%﹕50%, and the addition of cellulose could further enhance the fermentation quality and improve the nutritional composition.