以不同年份再植桃园根系土壤为材料，探究再植桃园微生物群落结构的变化情况，并进一步揭示不同年份的再植桃园微生物群落和土壤养分之间的关系，以期为桃树再植病调控提供理论依据。分别收集非再植（NRS）和再植（RS）(再植1年RS1、再植3年RS3、再植5年RS5、再植7年RS7、再植9年RS9、再植11年RS11)桃园桃树的根际土壤，利用高通量测序技术测定土壤细菌和真菌群落的多样性，同时采用RDA分析土壤微生物群落与土壤环境因子之间的关系。结果显示，RS早期（1-5年）的土壤养分含量低于NRS，但随着桃树种植年限的增加，它们之间的差异逐渐缩小，直至达到相近的水平。细菌和真菌群落的alpha多样性指数表明，RS比NRS含有更高丰度的细菌和真菌OUT含量。NMDS和ANOSIM分析表明，土壤细菌和真菌群落显著受种植年限影响（p<0.01），其变化主要发生在种植1年和9年。从目的分类水平看，再植桃园土壤中，Sphingobacteriales, Burkholderiales 和 Actinomycetales显著发生变化。一些与生物修复相关的细菌，如Burkholderiales目 和 Intrasporangiaceae纲，以及一些有害的病原真菌，如Penicillium属 和 Ophiostomatales纲,在再植桃园中显着增加（LDA> 3.0）。此外， RDA结果表明微生物群落的组成与环境各因子（pH、AP、AN 和 AK）间存在密切相关。从细菌门的分类水平看，这些环境变量与Acidobacteria, Chloroflexi, 和 Actinobacteria呈正相关，与Proteobacteria 和 Firmicutes呈负相关。在真菌门水平中，Basidiomycota门在 pH、AP 和 AN 增加的环境中增强，而Ascomycota, Chytridiomycota 和 Zygomycota门与 AK 呈正相关。RS的细菌和真菌群落多样性高于NRS，桃树再植病害的发生与土壤微生物群落的变化密切相关。我们的研究结果详细阐明了不同年份的 NRS 和 RS微生物群落的变化情况以及两者之间土壤理化和微生物群落变化之间的关系。这些结果使人们更加深入的了解再植桃园微生物群落的变化，为桃树再植病的解决提供思路。

本研究以41个代表性的玉米自交系通过不完全双列杂交产生了737个杂种F1的多杂种群体（MPH），将MPH群体分别种植在干旱和正常滴水处理下，利用38737个单核苷酸多态性标记（SNPs）对41份亲本进行了全基因组扫描。41份亲本自交系间的遗传距离为0.05到0.74之间，依据遗传距离可以将其划分为5个杂种优势群。根据不同杂种优势群产生杂交种的表型（产量、生育期、株高），研究认为BSSS×NSS、NSS×SPT和BSSS×SPT这3种杂优模式在中国机收玉米育种中具有较大的利用价值。研究一般配合力和特殊配合力的比值表明，正常滴水下加性效应对单株产量的的影响较大，而在干旱处理下非加性效应对产量的影响力更大。干旱条件下高产的玉米杂交种其亲本之一必须是配合力较高或者抗旱性较好的玉米自交系。在一定的遗传距离（GD）范围内，GD和杂种产量和产量杂种优势呈正相关。本研究认为杂种优势是亲本优势基因位点逐步累加和亲本间最佳遗传距离共同作用形成的，干旱处理下的产量杂种优势主要由非加性效应决定的。 

西瓜(Citrullus lanatus (Thunb.)Matsum. & Nakai)是世界范围内种植的一种重要的瓜类作物。西瓜果实品质、育性、结实率与雄花发育密切相关。本研究通过细胞学观察，对西瓜新品种‘新特大郑抗9号’雄花发育的不同阶段进行了区分，并进行了转录组测序分析。对花药进行醋酸洋红染色，并测定未开放雄花的纵横径。对花药不同发育时期的细胞学观察表明，花药从四分体生长到成熟期，其纵横径逐渐增大，雄花的花蕾长度在发育过程中也发生了显著的变化。对花药发育的四分体期(A组)、单核期(B组)、双核期(C组)和成熟期(D组)四个发育时期进行转录组测序分析。结果表明，四个阶段总共发现了16288个差异表达基因(DEGs)，随着发育阶段的延伸，各比较组间的DEGs数量逐渐增加，6个比较组(A-VS-B、A-VS-C、A-VS-D、B-VS-C、B-VS-D和C-VS-D)的DEGs分别为2014、3259、4628、1490、3495和1132个。GO和KEGG富集分析表明，DEGs主要富集于细胞组分、淀粉和蔗糖代谢、苯丙类生物合成和戊糖合成等途径。最后，我们在6个比较组中共筛选了59个DEGs，有趣的是，我们发现一个花粉特异表达蛋白(Cla001608)显著下调(log2Fold Change值高达17.32)，这表明它可能在雄花发育中起重要作用。本研究为了解西瓜雄性花发育阶段的分子基础提供了依据，并有助于优势杂交育种。

In vitro gynogenesis is an important tool used in haploid or homozygous double-haploid plant breeding.  However, because of low repeatability, embryoid induction rate and quality, the molecular mechanisms remain poorly understood.  Heat shock treatment can promote the transformation of the gametophytic pathway into the sporophyte pathway, which induces the occurrence of haploid.  In this study, unfertilized ovaries were heat shocked for 0 h (A0) before flowering and for 0 h (A1), 4 h (A3), 8 h (A5), 12 h (A7), and 24 h (A8), respectively, at 37°C at the first day of the flowering stage.  The ovule enlargement rate was increased from 0% at 25°C to 96.8% at 37°C (24 h treatment).  Thus, we aimed to investigate the gene expression patterns in unfertilized ovules of watermelon after different periods of heat shock by using RNA-Seq technology.  The results showed that compared with A3, A5, A7, and A8, the biosynthesis of amino acid, glycine, serine and threonine metabolic pathways in A1 has changed significantly.  This indicated that heat shock treatment affected the synthesis and transformation of amino acids during ovule expansion.  The transcriptome data suggested gene expressions of ovule growth were significantly changed by heat-specific influences.  The results provide new information on the complex relationship between in vitro gynogenesis and temperature.  This provides a basis for further study of the mechanism of heat shock affecting the expansion of watermelon ovule. 

     Heterosis is an important biological phenomenon, and it has been used to increase grain yield, quality and resistance to abiotic and biotic stresses in many crops. However, the genetic mechanism of heterosis remains unclear up to now. In this study, a set of 184 chromosome segment substitution lines (CSSLs) population, which derived from two inbred lines lx9801 (the recurrent parent) and Chang 72 (the donor parent), were used as basal material to construct two test populations with the inbred lines Zheng 58 and Xun 9058. The two test populations were evaluated in two locations over two years, and the heterotic loci for plant height and ear height were identified by comparing the performance of each test hybrid with the corresponding CK at P<0.05 significant level using one-way ANOVA analysis and Duncan’s multiple comparisons. There were 24 and 29 different heterotic loci (HL) identified for plant height and ear height in the two populations at two locations over two years. Three HL (hlPH4a, hlPH7c, hlPH1b) for plant height and three (hlEH1d, hlEH6b, hlEH1b) for ear height were identified in the CSSLs×Zheng 58 and CSSLs×Xun 9058 populations as contributing highly to heterosis performance of plant height and ear height across four environments. Among the 29 HL identified for ear height, 12 HL (41.4%) shared the same chromosomal region associated with the HL (50.0%) identified for plant height in the same test population and environment.

Wheat grain natural transverse sections of 12 periods were observed and analyzed using scanning electron micrographs technology and Bio-Quant system IV image analyzer in order to detect the developing process of A- and B-type starch granules. In addition, the chemical composition and starch granule-bound proteins (SGPs) of A- and B-type starch granules were tested and analyzed. The results showed that A-type starch granules in wheat began from 3 d post anthesis (DPA) till grain maturing and B-type starch granules occured after 15 DPA till grain maturing. Approximately 98.5% of chemical compositions in both A- and B-type starch granules were amylose and amylopectin, and more than half of which were amylopectin. The amylopectin contents, average chain length, and chain length distribution (degree of polymerization> 40) of amylopectin in A-type starch granules were significant higher than that of B-type starch granules. SGP-145, SGP- 140, and SGP-26 kD were associated with A-type starch formation in wheat grain.