本研究构建了一个由265个组合所构成的永久F₂（IF₂）群体，将IF₂群体以及相应的RIL亲本分别于2017年和2018年种植于北京上庄和河南开封两个地点，我们对穗行数（RN）、行粒数（KNPR）、穗长（EL）、穗粗（ED）、十粒厚（TKT）、单穗重（EW）、穗粗（CD）、粒长（KL）、粒宽（KW）、穗粒重（GW）、百粒重（HKW）、籽粒产量（GY）等12个果穗相关性状进行调查，然后用R/qtl软件对该12个性状作单环境QTL分析，结果表明，在四个种植环境下共鉴定到165个QTL，单个QTL可以解释0.1%-12.66%的表型变异。其中，19个QTL于多环境下被鉴定到，我们称之为“稳定QTL”。此外，经过对显性度的分析，发现约44.85%的QTL表现出超显性效应，约12.72%的QTL表现出显性效应。最后，我们鉴定了35个基因组多效性区间，这些区间分别包含两个及以上QTL。同时，通过对RN、EL、ED和EW四个性状的杂种优势数据集进行分析，我们鉴定出17个的杂种优势相关QTL位点。本研究得到的结果为理解玉米果穗相关性状的遗传机制提供了新的见解，并拓展了我们对玉米杂种优势遗传基础的理解。

Visualization of simulated crop growth and development is of significant interest to crop research and production.  This study aims to address the phenomenon of organs cross-drawing by developing a method of collision detection for improving vivid 3D visualizations of virtual wheat crops.  First, the triangular data of leaves are generated with the tessellation of non-uniform rational B-splines surfaces.  Second, the bounding volumes (BVs) and bounding volume hierarchies (BVHs) of leaves are constructed based on the leaf morphological characteristics and the collision detection of two leaves are performed using the Separating Axis Theorem.  Third, the detecting effect of the above method is compared with the methods of traditional BVHs, Axis-Aligned Bounding Box (AABB) tree, and Oriented Bounding Box (OBB) tree.  Finally, the BVs of other organs (ear, stem, and leaf sheath) in virtual wheat plant are constructed based on their geometric morphology, and the collision detections are conducted at the organ, individual and population scales.  The results indicate that the collision detection method developed in this study can accurately detect collisions between organs, especially at the plant canopy level with high collision frequency.  This collision detection-based virtual crop visualization method could reduce the phenomenon of organs cross-drawing effectively and enhance the reality of visualizations.

Seasonal soil freeze-thaw events may enhance soil nitrogen transformation and thus stimulate nitrous oxide (N₂O) emissions in cold regions.  However, the mechanisms of soil N₂O emission during the freeze-thaw cycling in the field remain unclear.  We evaluated N₂O emissions and soil biotic and abiotic factors in maize and paddy fields over 20 months in Northeast China, and the structural equation model (SEM) was used to determine which factors affected N₂O production during non-growing season.  Our results verified that the seasonal freeze-thaw cycles mitigated the available soil nitrogen and carbon limitation during spring thawing period, but simultaneously increased the gaseous N₂O-N losses at the annual time scale under field condition.  The N₂O-N cumulative losses during the non-growing season amounted to 0.71 and 0.55 kg N ha^–1 for the paddy and maize fields, respectively, and contributed to 66 and 18% of the annual total.  The highest emission rates (199.2–257.4 μg m^–2 h^–1) were observed during soil thawing for both fields, but we did not observe an emission peak during soil freezing in early winter.  Although the pulses of N₂O emission in spring were short-lived (18 d), it resulted in approximately 80% of the non-growing season N₂O-N loss.  The N₂O burst during the spring thawing was triggered by the combined impact of high soil moisture, flush available nitrogen and carbon, and rapid recovery of microbial biomass.  SEM analysis indicated that the soil moisture, available substrates including NH₄⁺ and dissolved organic carbon (DOC), and microbial biomass nitrogen (MBN) explained 32, 36, 16 and 51% of the N₂O flux variation, respectively, during the non-growing season.  Our results suggested that N₂O emission during the spring thawing make a vital contribution of the annual nitrogen budget, and the vast seasonally frozen and snow-covered croplands will have high potential to exert a positive feedback on climate change considering the sensitive response of nitrogen biogeochemical cycling to the freeze-thaw disturbance.   

The germplasm resources for the S-type male sterility is rich in maize and it is resistant to Bipolaris maydis race T and CI, but the commercial application of S-type cytoplasmic male sterility (CMS-S) in maize hybrid industry is greatly compromised because of its common fertility instability. Currently, the existence of multiple minor effect loci in specific nuclear genetic backgrounds was considered as the molecular mechanism for this phenomenon. In the present study, we evaluated the fertility segregation of the different populations with the fertility instable material FIL-H in two environments of Beijing and Hainan, China. Our results indicated that the fertility instability of FIL-H was regulated by multiple genes, and the expression of these genes was sensitive to environmental factors. Using RNA sequencing (RNA-seq) technology, transcriptomes of the sterile plants and partially fertile plants resulted from the backcross of FIL-H×Jing 724 in Hainan were analyzed and 2 108 genes with different expression were identified, including 1 951 up-regulated and 157 down-regulated genes. The cluster analysis indicated that these differentially expressed genes (DEGs) might play roles in many biological processes, such as the energy production and conversion, carbohydrate metabolism and signal transduction. In addition, the pathway of the starch and sucrose metabolism was emphatically investigated to reveal the DEGs during the process of starch biosynthesis between sterile and partially fertile plants, which were related to the key catalytic enzymes, such as ADP-G pyrophosphorylase, starch synthase and starch branching enzyme. The up-regulation of these genes in the partially fertile plant may promote the starch accumulation in its pollen. Our data provide the important theoretical basis for the further exploration of the molecular mechanism for the fertility instability in CMS-S maize.

  Calcineurin (Cn or CaN) is implicated in the control of skeletal muscle fiber phenotype and hypertrophy. However, little information is available concerning the expression of Cn in chickens. In the present study, the expression of two Cn subunit genes (CnAα and CnB1) was quantified by qPCR in the lateral gastrocnemius (LG, mainly composing of red fast-twitch myofibers), the soleus (mainly composing of red slow-twitch myofibers) and the extensor digitorum longus (EDL, mainly composing of white fast-twitch myofibers) from Qingyuan partridge chickens (QY, slow-growing chicken breed) and Recessive White chickens (RW, fast-growing chicken breed) on different days (1, 8, 22, 36, 50 and 64 days post-hatching). Although CnAα and CnB1 gene expressions were variable with different trends in different skeletal muscles in the two chicken breeds during postnatal growth, it is highly muscle phenotype and breed specific. In general, the levels of CnAα and CnB1 gene expressions of the soleus were lower than those of EDL and LG in both chicken breeds at the same stages. Compared between the two chicken breeds, the levels of CnAα gene expression of the three skeletal muscles in QY chickens were higher than those in RW chickens on days 1 and 22. However, on day 64, the levels of both CnAα and CnB1 gene expressions of the three skeletal muscles were lower in QY chickens than those in RW chickens. Correlation analysis of the levels of CnAα and CnB1 gene expressions of the same skeletal muscle showed that there were positive correlations for all three skeletal muscle tissues in two chicken breeds. These results provide some valuable clues to understand the role of Cn in the development of chicken skeletal muscles, with a function that may be related to meat quality.

The spatial-temporal patterns of grain production and consumption have an important influence on the effective national grain supply on condition of tight balance in the total grain amount in China. In this paper, we analyze the spatial-temporal patterns of grain production, consumption and the driving mechanism for their evolution processes in China. The results indicate that both gravity centers of grain production and consumption in China moved toward the northern and eastern regions, almost in the same direction. The coordination of grain production and consumption increased slightly from 1995 to 2007 but decreased from 2000 to 2007. There is a spatial difference between the major districts of output increase and the strong growth potential in grain consumption, which indicates an increasing difficulty in improving the regional coordination of grain production and consumption. The movement of the gravity center of grain production is significantly correlated with regional differences in grain production policy, different economic development models, and spatial disparity of land and water resource use. For grain consumption, the main driving factors include rapid urbanization, the upgrade of food consumption structure, and distribution of food industries.