株型和叶色是棉花纤维产量的重要影响因素。本研究基于遗传分析、茎秆石蜡切片和植物激素处理方法，发现棉花矮红株突变体（DR）是一个赤霉素敏感型突变体，由一个单显性基因位点突变引起，将其命名为GhDR。通过BSA-seq结合靶向测序基因型检测（GBTS）方法将控制突变性状基因定位在A09 染色体约197 kb的候选区间内，包含 25 个注释基因。基于候选基因的注释信息，及其在突变体和正常植株之间的序列和表达差异，GH_A09G2280基因被认为是控制矮红突变体表型的最佳候选基因。在DR突变体GhDR/GH_A09G2280基因编码区发现了一个2 bp的缺失，导致GhDR基因产生移码突变，蛋白翻译提前终止。GhDR是拟南芥AtBBX24的同源基因，编码B-box锌指蛋白。移码缺失导致GhDR 的C末端缺失了核定位结构域和VP结构域，并改变了其亚细胞定位结果。比较转录组分析表明，在DR突变体中，参与赤霉素生物合成和信号转导的关键基因下调表达，而与赤霉素降解和花青素生物合成相关基因上调表达。本研究初步揭示了GhDR基因同时调控棉花株型和花青素积累的潜在分子机制。

本研究制备了不同粒径的聚脲高效氯氟氰菊酯微囊，均有一定程度的塌陷，小粒径微囊塌陷更明显。它们的平均粒径分别为1.38 μm ( MC-S )、5.13μm ( MC-M )和10.05 μm ( MC-L )，囊壳厚度分别为39.6、50.3和150.1 nm。小粒径微囊具有更快的释放性能；与MC-M和MC-L相比，MC-S组对小地老虎的生物活性更高，对花生叶片的亲和力更好(由耐雨水冲刷可知)；微囊均表现出随光照增强释放加快的趋势；与EC组相比，微囊降解都较慢，其中MC-L降解最慢。为了获得既具有速效性又具有持效期的微囊，将MC-S、MC-M和MC-L按2:1、1:1和1:2的比例两两混合。花生叶面喷雾场景下，9个供试微囊组合中MC-S:MC-L以1:2混合药效最好，持效期比乳油延长3倍。因此，不同粒径微囊精准组合可以调控农药的防治效果，为更好地利用农药提供策略。

本研究构建了一个可直接估计空间不确定性的集合式机器学习模型，即分位数回归森林，定量土体深度与环境条件之间的关系。将该模型与丰富的环境协同变量结合，预测了位于我国西北地区、面积为14万km²的黑河流域的土体深度空间分布，估算了制图结果的空间不确定性。使用了275个土体深度观测样本和26个环境协同变量数据。结果显示，模型预测精度R²为0.587，RMSE为2.98 cm（平方根尺度），可解释近60%的土体深度变异。土体深度图清晰地展示了土体深度的区域分布模式和局部细节。谷底、平原等低平低洼景观部位土体深度较大，而山坡、山脊、台地等高陡景观部位土体深度较小；绿洲内土体深度明显大于绿洲之外的荒漠地区，冲积平原中部土体深度明显大于边缘地带，而湖泊平原中部土体深度明显小于边缘地带。高的预测不确定性主要出现在可达性差、缺少样本的区域。分析发现，土壤发生过程和地貌过程共同塑造了该流域土体深度的空间模式，但地貌过程起主导作用。这一点可能也适用于世界上其它寒旱地区类似的“高寒山地-平原绿洲-荒漠戈壁”流域。

在本研究中，我们采用固相微萃取SPME结合气相质谱联用技术比较了这两个葡萄品种果实发育过程中香气组分和含量的差异，并通过荧光定量PCR法分析了香气合成途径，比如LOX-HPL、MEP和MVA，酶编码基因的表达差异。结果发现巨峰果实成熟过程中共检测到12种酯类香气物质，并且主要在转色后含量丰富，但87-1葡萄中没有检测到酯类香气物质；87-1葡萄果实中检测到了14种萜烯类香气物质，含量丰富，并以里那醇为主，但在巨峰果实中仅检测到少量的萜烯类香气物质；荧光定量PCR的结果表明醇酰基转移酶编码基因VvAAT的低表达可能是87-1葡萄酯类香气含量低的主要原因，而MEP代谢途径酶编码基因的低表达，特别是里那醇合成酶编码基因VvPNLinNer1的低表达可能是巨峰葡萄中萜烯类香气物质含量低的原因。本研究将有助于对葡萄香气代谢机理认识的加深，并为葡萄香气品质改良提供理论指导。

Received  5 January, 2018    Accepted  7 May, 2018

Carex rigescens (Franch.) V. Krecz is a wild turfgrass perennial species in the Carex genus that is widely distributed in salinised areas of northern China.  To investigate genome-wide salt-response gene networks in C. rigescens, transcriptome analysis using high-throughput RNA sequencing on C. rigescens exposed to a 0.4% salt treatment (Cr_Salt) was compared to a non-salt control (Cr_Ctrl).  In total, 57 742 546 and 47 063 488 clean reads were obtained from the Cr_Ctrl and Cr_Salt treatments, respectively.  Additionally, 21 954 unigenes were found and annotated using multiple databases.  Among these unigenes, 34 were found to respond to salt stress at a statistically significant level with 6 genes up-regulated and 28 down-regulated.  Specifically, genes encoding an EF-hand domain, ZFP and AP2 were responsive to salt stress, highlighting their roles in future research regarding salt tolerance in C. rigescens and other plants.  According to our quantitative RT-PCR results, the expression pattern of all detected differentially expressed genes were consistent with the RNA-seq results.  Furthermore, we identified 11 643 simple sequence repeats (SSRs) from the unigenes.  A total of 144 amplified successfully in the C. rigescens cultivar Lüping 1, and 69 of them reflected polymorphisms between the two genotypes tested.  This is the first genome-wide transcriptome study of C. rigescens in both salt-responsive gene investigation and SSR marker exploration.  Our results provide further insights into genome annotation, novel gene discovery, molecular breeding and comparative genomics in C. rigescens and related grass species.

To deal with the global and regional issues including food security, climate change, land degradation, biodiversity loss, water resource management, and ecosystem health, detailed accurate spatial soil information is urgently needed.  This drives the worldwide development of digital soil mapping.  In recent years, significant progresses have been made in different aspects of digital soil mapping.  The main purpose of this paper is to provide a review for the major progresses of digital soil mapping in the last decade.  First, we briefly described the rise of digital soil mapping and outlined important milestones and their influence, and main paradigms in digital soil mapping.  Then, we reviewed the progresses in legacy soil data, environmental covariates, soil sampling, predictive models and the applications of digital soil mapping products.  Finally, we summarized the main trends and future prospect as revealed by studies up to now.  We concluded that although the digital soil mapping is now moving towards mature to meet various demands of soil information, challenges including new theories, methodologies and applications of digital soil mapping, especially for highly heterogeneous and human-affected environments, still exist and need to be addressed in the future.

Abscisic acid (ABA), as one of the foremost signaling molecules in plants, is an important hormone which plays versatile functions in regulating developmental process and adaptive stress process.  A set of introgression lines were previously generated via a backcrossing program using an elite indica cultivar rice Teqing (O. sativa L.) as recipient and an accession of Yuanjiang common wild rice (O. rufipogon Griff.) as donor.  In this study, the previously developed introgression lines were evaluated for ABA sensitivity.  Here we reported that a total of 14 quantitative trait loci (QTLs) associated with ABA sensitivity were identified.  An ABA sensitive introgression line, YIL53, was identified and characterized.  Physiological characterization, including chlorophyll content, malondialdehyde content, soluble sugar content, and stomata movement, demonstrated that YIL53 exhibited the characteristics associated with ABA sensitivity.  Genotypic analysis revealed that YIL53 harbored one QTL related to ABA sensitivity, qASS1-2, which was located on chromosome 1 within one introgressed segment derived from the Yuanjiang common wild rice.  Furthermore, the qASS1-2 was finally narrowed down to a 441-kb region between simple sequence repeats (SSR) marker RM212 and single nucleotide polymorphism (SNP) marker M3 using the segregation population derived from the cross between Teqing and YIL53, and three candidate genes associated with ABA sensitivity were identified using a strategy combined gene expression analysis with QTL mapping.  Identification of the QTLs related to ABA sensitivity and characterization of the ABA sensitive line YIL53 would provide a helpful basis for isolating novel genes related to ABA sensitivity.  

Peanut (Arachis hypogaea L.), an improtant oil crop, usually encounters drought stress in the process of growth and development, especially at pre-flowering stage.  In order to gain insight into the drought tolerance potentials based on osmolyte accumulation and metabolism of proline aspects of peanut, pot experiments were conducted with a split-plot design in Tai’an, Shangdong Province, China in 2013 and 2014.  Pre-flowering drought (PFD) stress and optinum irrigation (control, CK) were served as the main plots and the two peanut cultivars Shanhua 11 and Hua 17 served as sub-plots.  Shanhua 11 was drought-tolerant cultivar and Hua 17 was drought-sensitive.  The content of soluble sugars, soluble protein, free proline and other free amino acids, the activities of enzymes involved in proline metabolism, and malondialdehyde (MDA) content and ion leakage were all investigated in the two cultivars at pre-flowering stage.  Results showed that PFD stress significantly increased the levels of soluble protein, free proline and free amino acid, and increased Δ¹-pyrroline-5-carboxylate synthetase (P-5-CS, EC 2.7.2.11) activity in the leaves of drought-tolerant and drought-sensitive cultivars.  The activity of proline dehydrogenase (proDH) (EC 1.5.99.8) decreased under PFD stress in both cultivars.  The leaves of the tolerant cultivar maintained higher increments of osmolyte levels, lower increments of MDA content and ion leakage, as well as a higher increased proportion of P-5-CS activity and higher inhibited proportion of proDH activity under water stress compared with the drought-sensitive cultivar.  The study suggests that proline accumulation in peanut leaves under PFD can be explained by the higher enhanced activities of P-5-CS and higher inhibition of proDH.  The results will provide useful information for genetic improvement of peanut under drought tolerance.

The highbush blueberry (Vaccinium corymbosum), Duke, was used to construct a de novo transcriptome sequence library and to perform data statistical analysis.  Mega 4, CLC Sequence Viewer 6 software, and quantitative PCR were employed for bioinformatics and expression analyses of the basic helix-loop-helix (BHLH) transcription factors of the sequencing library.  The results showed that 28.38 gigabytes of valid data were obtained from transcriptome sequencing and were assembled into 108 033 unigenes.  Functional annotation showed that 32 244 unigenes were annotated into Clusters of Orthologous Groups (COG) and Gene Ontology (GO) databases, whereas the rest of the 75 789 unigenes had no matching information.  By using COG and GO classification tools, sequences with annotation information were divided into 25 and 52 categories, respectively, which involved transport and metabolism, transcriptional regulation, and signal transduction.  Analysis of the transcriptome library identified a total of 59 BHLH genes.  Sequence analysis revealed that 55 genes of that contained a complete BHLH domain.  Furthermore, phylogenetic analysis showed that BHLH genes of blueberry (Duke) could be divided into 13 sub-groups.  PCR results showed that 45 genes were expressed at various developmental stages of buds, stems, leaves, flowers, and fruits, suggesting that the function of BHLH was associated with the development of different tissues and organs of blueberry, Duke.  The present study would provided a foundation for further investigations on the classification and functions of the blueberry BHLH family.

Pepper (Capsicum annuum. L.) is a widely cultivated vegetable crop worldwide and has the second largest planting area and the first largest vegetable output and value in China.  Pepper root-knot nematode (Meloidogyne spp.) is one of the most serious pests of pepper, which caused huge losses every year.  Previous studies showed that the Me3 gene is resistant to a wide range of Meloidogyne species, including M. arenaria, M. javanica, and M. incognita.  HDA149, a double haploid pepper genotype, harboring the root-knot nematode resistance gene Me3, was used to construct bacterial artificial chromosome library (BAC) via the vector of CopyControl^TM pCC1 in this study.  The library consists of 210 200 BAC clones and is equivalent to 5.3 pepper genomes.  The average insert size is 95 kb, and most of them are 90–120 kb; but the empty clones are less than 3%.  In order to screen the BAC library easily, 550 super pools with 384 BAC clones of each pool were further developed in this study.  Specific primers from Me3 gene locus were used for BAC library screening, and more than 20 positive BAC clones were obtained.  Then the selected positive BAC clones were analyzed by restriction enzyme digestion, BAC-end sequencing, marker development, and new positive BAC clones exploration, respectively.  Finally, the contig with total length of about 300 kb linked to the Me3 locus was constructed based on chromosome walking strategy, which made a solid foundation for the cloning of the important root-knot nematode resistance gene Me3.

Rice (Oryza sativa L.), a tropical and subtropical crop, is susceptible to low temperature stress during seedling, booting, and flowering stages, which leads to lower grain quality levels and decreasing rice yields. Cold tolerance is affected by multiple genetic factors in rice, and the complex genetic mechanisms associated with chilling stress tolerance remain unclear. Here, we detected seven quantitative trait loci (QTLs) for cold tolerance at booting stage and identified one cold tolerant line, SIL157, in an introgression line population derived from a cross between the indica variety Guichao 2, as the recipient, and Dongxiang common wild rice, as the donor. When compared with Guichao 2, SIL157 showed a stronger cold tolerance during different growth stages. Through an integrated strategy that combined QTL-mapping with expression profile analysis, six candidate genes, which were up-regulated under chilling stress at the seedling and booting developmental stages, were studied. The results may help in understanding cold tolerance mechanisms and in using beneficial alleles from wild rice to improve the cold tolerance of rice cultivars through molecular marker-assisted selection.

A rapid and reliable method was developed for analysis of ethephon residues in maize, in combination with the investigation of its dissipation in field condition and stabilities during the sample storage. The residue analytical method in maize plant, maize kernel and soil was developed based on the quantification of ethylene produced from the derivatization of ethephon residue by adding the saturated potassium hydroxide solution to the sample. The determination was carried out by using the head space gas chromatography with flame ionization detector (HS-GC-FID). The limit of quantification (LOQ) of the method for maize plant was 0.05, 0.02 mg kg–1 for maize kernel and 0.05 mg kg–1 for soil, respectively. The fortified recoveries of the method were from 84.6–102.6%, with relative standard deviations of 7.9–3.8%. Using the methods, the dissipation of ephethon in maize plant or soil was investigated. The half life of ethephon degradation was from 0.6 to 3.3 d for plant and 0.7 to 5.7 d for soil, respectively. The storage stabilities of ethephon residues were determined in fresh and dry kernels with homogenization and without homogenization process. And the result showed that ethephon residues in maize kernels were stable under –18°C for 6 mon. The results were helpful to monitor the residue dissipation of ethephon in the maize ecosystem for further ecological risk assessment.

The objective of this study was to determine the relationship between seed yield and other important agronomic traits ofearly-maturing rapeseed as a rotation crop in a double-cropping rice area using Pearson’s correlation coefficient as well asto estimate direct and indirect effects of specific yield component traits on seed yield via path analysis. Nineteen rapeseedgenotypes were grown at ten environments in South China during 2008-2009 and 12 characters were evaluated. Analysisof variance showed that environment had a significant impact on all characters. For most characters the genotype byenvironment interaction was weak and not statistically significant. Simple correlation analysis indicated that the numberof primary branches (PB), number of pods on the main raceme (PR), and number of seeds per pod made significantcontributions to seed yield per plant (SYP), while 1 000-seed weight was negatively correlated with SYP (r=-0.485, P<0.05).Furthermore, number of pods per plant (PP), PB, and PR had the greatest direct effects on SYP. In addition, PP and PB werethe best indicators to predict seed yield in stepwise regression analysis. Finally, yield component differences betweenearly- and medium-maturity varieties were compared; this showed that to improve the seed yield of early varieties, moreemphasis should be given to increase PP, PB, and PR, and reduce plant height and shortening of growth duration inbreeding practice.

Data assimilation in agricultural remote sensing research is of great significance to integrate with remote sensing observations and model simulations for parameters estimation. The present investigation not only designed and realized the Ensemble Kalman Filtering algorithm (EnKF) assimilation by combing the crop growth model (CERES-Wheat) with remote sensing data, but also optimized and updated the key parameters (LAI) of winter wheat by using remote sensing data. Results showed that the assimilation LAI and the observation ones agreed with each other, and the R2 reached 0.8315. So assimilation remote sensing and crop model could provide reference data for the agricultural production.