Genetic components of pod shattering in soybean

Half diallel crosses among ten pure breeding lines of soybean were made in 1997 and 1998 to study the inheritance of pod shattering in soybean. Evaluation for pod shattering among F₂ segregating populations was carried out in an oven set at 80 ^°C for 12 hours. Diallel analysis was carried out to estimate genetic parameters and detect presence of non allelic interaction of genes affecting pod shattering. Hayman's diallel analysis indicated significant variation of Wr + Vr and Wr – Vr over arrays, suggesting epistatic gene action. Similarly results from a joint regression coefficient over replications were significantly (p < 0.05) different from unity and zero, suggesting presence of non allelic interaction of genes. The intercept was positive, suggesting partial dominance for the shattering trait. Both general combining ability (GCA) and specific combining ability (SCA) effects were significant (p < 0.05). This revised version was published online in July 2006 with corrections to the Cover Date.     

大豆鲜荚籽粒上位性QTL及其互作效应分析

荚粒是大豆主要的收获器官,直接影响鲜食大豆品种审定和产品出口。然而,荚粒性状由多基因控制,目前主要集中在加性数量性状位点（quantitative trait loci,QTL）发掘方面,对上位性QTL及其互作效应报道甚少。鉴于此,通过鉴定大豆重组自交系（recombinant inbred line,RIL）群体2年4种环境条件下鲜荚和籽粒的长度、宽度、重量等相关性状,发掘控制其上位性QTLs,并研究其互作效应,结果发现,8种测试性状共检测到321对“加性×加性”上位性QTLs,涉及所有染色体,构成复杂的上位性QTLs互作网络,其中包括144对正向效应和177对负向效应QTLs,并以13号染色体分布数量最多;进一步分析发现,存在34对“一因多效”加性×加性上位性QTLs,且加性×加性上位性QTLs间的互作贡献率为1.89%~4.85%,高于其与环境互作贡献率,说明遗传因素为主;上述34对QTLs涉及18条染色体,其中包含定位区间一致的23对“一因多效”QTLs,并有6组上位性QTLs以“一对多”方式发挥功能,16组以“一对一”方式发挥作用。上述结果不仅为实现大豆荚粒性状精准分子遗传改良提供了选择标记,并为进一步揭示大豆荚粒性状分子遗传机制提供了依据。     

水稻米粒延伸性QTLs定位和基因型与环境互作分析

 利用协青早B/密阳46所构建的重组自交系群体及其相应分子遗传图谱，在海南和杭州两地试验，以延伸率作为米粒延伸性考察指标，检测QTL主效应、上位性效应和基因型×环境互作效应的遗传分析方法，进行联合检测分析。结果表明，该性状两地间的平均表现和群体分布特征较为相似，但两地间表型值相关系数却较小。试验检测到1个控制该性状的QTL基因qCRE 6,其增效基因来自于父本，提高3.99%的米粒延伸率，可解释5.30%的表型变异，它不存在与环境间显著互作。另外，还检测到2对上位性互作基因，即qCRE 2与qCRE 5 1、qCRE 5 2与qCRE 7,前者与环境间存在有显著的基因型×环境互作，在杭州有增加米粒延伸性的效果。     

Triple test cross analysis in rice

Summary The triple test cross analysis in rice brought out that significant epistasis is present for most of the characters in the three crosses except for 100 grain weight in two crosses (Co 39 × Co 41) and (Co 39 × Co 40) and plant height in one cross (Co 39 × IR 20). Epistasis of i (homozygote × heterozygote) and l (heterozygote × heterozygote) interactions are also detected in all the three crosses. The D component was significant for all the traits in the three crosses and H was significant in cross Co 39 × Co 41 for all characters. For tiller number in cross Co 39 × IR 20 and for tiller number and 100 grain weight in cross Co 39 × Co 40, the H component was not significant. In all the crosses D component was higher than H.     

Epistatic effects between pairs of the growth hormone secretagogue receptor 1a,growth hormone,growth hormone receptor,non‐SMC condensin I complex,subunit G and stearoyl‐CoA desaturase genes on carcass,price‐related and fatty acid composition traits in Japanese Black cattle

Growth hormone secretagogue receptor 1a (GHSR1a), growth hormone (GH), growth hormone receptor (GHR), non‐SMC condensin I complex, subunit G (NCAPG) and stearoyl‐CoA desaturase (SCD), are known to play important roles in growth and lipid metabolisms. Single and epistatic effects of the five genes on carcass, price‐related and fatty acid (FA) composition traits were analyzed in a commercial Japanese Black cattle population of Ibaraki Prefecture. A total of 650 steers and 116 heifers for carcass and price‐related traits, and 158 steers for FA composition traits were used in this study. Epistatic effects between pairs of the five genes were found in several traits. Alleles showing strain‐specific differences in the five genes had significant single and epistatic effects in some traits. The data suggest that a TG‐repeat polymorphism of the GHSR1a.5′UTR‐(TG)_n locus plays a central role in gene–gene epistatic interaction of FA composition traits in the adipose tissue of Japanese Black cattle.     

Generation mean analysis of horticultural traits in mid‐late cauliflower (Brassica oleracea L. var. botrytis) under sub temperate conditions of Western Himalayas

Suitable breeding procedure for crop improvement mainly depends on the type and relative amount of genetic components and presence of non‐allelic interactions. Therefore, the study was carried out during three successive rabi seasons 2013‐14, 2014‐15 and 2015‐16 in mid hill zone of North‐western Himalayas, India with objective to estimate the main genetic effects including digenic non‐allelic interactions controlling horticultural traits in cauliflower. The generation mean analysis was carried out on six generations (P₁, P₂, F₁, F₂, B₁ and B₂) of six crosses involving four diverse parents of cauliflower. The results obtained revealed that the nature and magnitude of gene effects differed in different crosses and showed importance of duplicate epistasis in the inheritance of curd diameter and curd size index, whose effect can be wiped out by following sophisticated selection procedure such as reciprocal recurrent selection and/or biparental mating in early segregating generation. Complementary type of epistasis was recorded in most of the cross combinations for the important yield traits, which indicates the importance of heterosis breeding for the development of high yielding varieties.     

用逐步回归鉴别上位性QTL互作标记的模拟研究

利用蒙特卡罗模拟对逐步回归分析在鉴别代表ＱＴＬ 上位性的互作遗传标记上的应用进行了详细研究⒚结果表明,逐步回归分析能够有效、准确地鉴别出反映ＱＴＬ上位性的互作遗传标记,并优于当前常用的双向方差分析⒚ＱＴＬ之间的紧密连锁会导致互作标记鉴别的分辨率降低,并使鉴别的效率出现扭曲⒚大样本和／或高遗传率可以从总体上提高互作标记准确鉴别的效率,而特定的互作标记鉴别的效率在很大程度上取决于它所代表的ＱＴＬ上位性的相对贡献率⒚显著水平也是影响互作标记鉴别效率的一个重要因子⒚本文建议在几种不同的显著水平下进行若干次逐步回归分析,并在确定适当的显著水平时考虑性状的遗传率及样本容量⒚     

甘蓝型油菜细胞核雄性不育性的遗传研究——Ⅰ.隐性核不育系9012A的遗传

研究结果表明:(1)甘蓝型油菜核不育系9012A不同于显性上位互作核不育,是一种新的基因互作核不育类型,其不育性受2对隐性重叠不育基因和1对隐性上位抑制基因互作控制,当隐性上位基因纯合时,对隐性不育基因起上位抑制作用。(2)在甘蓝型油菜中存在至少2套独立的不同隐性重叠不育基因,隐性上位基因与不同的隐性重叠不育基因之间的互作是非专一性的,这对于现有双基因隐性核不育杂种优势利用具有重要意义。 隐性上位互作核不育完全保持系的分离解决了传统隐性核不育杂种优势利用难点,为隐性核不育杂种优势利用开辟了新途径。这类核不育不仅在杂优育种实践中具有较高的开发利用价值,同时也是研究植物细胞核雄性不育机理的理想材料。     

不同生态环境下水稻穗部性状QTL鉴定

【目的】发掘与产量相关的穗粒性状QTL对进一步克隆和利用高产基因具有重要意义。【方法】以超级粳稻龙稻5号和典型高产籼稻中优早8号杂交衍生的重组自交系群体为试材,在4种环境下对穗部性状进行比较和QTL分析。【结果】共检测到63个穗部性状QTL,分布于除第9染色体外的11条染色体上。在4个环境下分别检测到27、27、18和35个QTL。其中,16个QTL能在2个环境下被检测到,12个在3个以上环境下稳定表达,分别占QTL总数的25.40%和19.05%;第1、3、4和5染色体的多效QTL簇能在不同环境下稳定表达,对穗部性状具有明显的调控作用。【结论】第3染色体STS3.3-STS3.6区间的qSNP3、第4染色体RM5688-RM1359区间的qSNP4.1是2个新的稳定表达的多效性QTL簇。此外,上位性效应是调控穗部性状的重要组分。     

QTL Detection and Epistasis Analysis for Heading Date Using Single Segment Substitution Lines in Rice(Oryza sativa L.)

Heading date of rice is a key agronomic trait determining cultivated areas and seasons and affecting yield. In the present study, five primary single segment substitution lines with the same genetic background were used to detect quantitative trait loci(QTLs) for heading date in rice. Two QTLs, q HD3 and q HD6 on the short arm of chromosome 3 and the short arm of chromosome 6, respectively, were identified under natural long-day(NLD). Nineteen secondary single segment substitution lines(SSSLs) and seven double segments pyramiding lines were designed to map the two QTLs and to evaluate their epistatic interaction between them. By overlapping mapping, q HD3 was mapped in a 791-kb interval between SSR markers RM3894 and RM569 and q HD6 in a 1 125-kb interval between RM587 and RM225. Results revealed the existence of epistatic interaction between q HD3 and q HD6 under natural long-day(NLD). It was also found that q HD3 and q HD6 had significant effects on plant height and yield traits, indicating that both of the QTLs have pleiotropic effects.