甘蓝型油菜隐性上位细胞核雄性不育三系的转育方法

对甘蓝型油菜隐性上位细胞核雄性不育纯合两型系、临保系和全不育系的转育方法进行了介绍。其要点是先转育隐性上位细胞核雄性不育纯合两型系,然后再通过回交转育主要农艺性状与纯合两型系相近或完全一致的相应的全不育临时保持系。具有方法简便,工作量小,见效快等优点。该方法正在应用于对REGMS118A类型细胞核雄性不育系的转育改良实践中。     

玉米穗部性状遗传分析

以两组PA 种质改良系J1255、J1401 与S122 杂交所形成的6 个世代为试验材料,采用郭平仲提出的世 代平均数分析方法对玉米穗长、穗粗、籽粒长、百粒重、穗粒重进行了遗传分析。结果表明;玉米穗长与百粒重的遗传 受基因的加性效应为主,显性效应次之;穗粗、籽粒长和穗粒重的遗传受基因的显性效应作用为主,加性效应次之; 上位性效应明显存在于穗部各性状的世代遗传变异中,其中,对于百粒重的遗传变异,上位性效应明显大于显性效 应,并以加性伊加性的上位性互作为主。     

Analysis of mode of inheritance of Fusarium wilt resistance in castor (Ricinus communis L.)

Castor (Ricinus communis L.) is an important industrial oilseed crop grown worldwide. Wilt caused by Fusarium oxysporum f.sp. ricini is a devastating disease in castor. The inheritance mode of wilt resistance was investigated. The F₁, F₂ and backcross generations of four crosses involving four resistant and three susceptible parents were developed. The role of digenic (R¹ and R²) epistatic interactions on wilt resistance was confirmed. The 15 : 1, 9 : 7 and 13 : 3 ratios indicated duplicate dominant, duplicate recessive and dominant and recessive epistatic interactions, respectively. Castor parents used in the crosses exhibited varied inheritance modes. All generations of a cross exhibited similar inheritance mode when parents were comparable. However, generations varied in inheritance mode when parents were not comparable in inheritance mode. These results would have practical interest when decisions are required regarding the choice of parents and methodology in resistance and hybrid breeding. The results also provided a basis for investigating molecular genetics of wilt resistance mechanisms.     

8种水旱环境下2个玉米群体穗部性状QTL间的上位性及环境互作效应分析

深入剖析干旱胁迫条件下玉米穗部性状的遗传机制可为玉米抗旱高产分子育种提供参考依据。以大穗型旱敏感自交系TS141为共同亲本,分别与小穗型强抗旱自交系廊黄和昌7-2杂交,构建了含有202个(LTPOP)和218个(CTPOP)家系的F2:3群体,在8种水旱环境下进行单穗重、穗轴重、穗粒重、百粒重、出籽率及穗长等6个穗部性状的表型鉴定,并采用复合区间作图法(CIM)和基于混合线性模型的复合区间作图法(MCIM)对其进行单环境和多环境联合数量性状位点(QTL)分析。结果表明,采用CIM法,单环境下在2套F2:3群体间检测到62个穗部性状QTL,其中干旱胁迫环境下检测到38个QTL,进一步在2套F2:3群体多个干旱胁迫环境下检测到10个稳定表达的QTL (sQTL),分别位于Bin 1.01–1.03、Bin 1.03–1.04、Bin 1.05、Bin 1.07、Bin 1.07–1.08、Bin 2.04、Bin 4.08、Bin 5.06–5.07、Bin6.05和Bin 9.04–9.06。采用MCIM法,联合分析定位到54个穗部性状联合QTL,其中24个表现显著的QTL与环境互作(QTL×E), 17对参与了显著的加性与加性/显性(AA/AD)上位性互作,其表型贡献率较低。这些研究结果可为系统地剖析玉米穗部性状的分子遗传机制提供理论依据;且这2套F2:3群体多个环境下检测到的sQTL可作为穗部性状改良的重要候选染色体区段,用于图位克隆或抗旱高产分子育种,但要注重环境及上位性互作效应的影响。     

数量性状全基因组关联分析中上位效应遗传位点检测方法研究进展

数量性状的表型变异受到大量效应微小的遗传位点和诸多环境因素的共同作用,但在数量性状的遗传研究领域,关于不同遗传位点之间加性效应与上位效应相对重要性的认识却存在着分歧。近年来,伴随着全基因组关联分析在人类及家养动物数量性状研究中的发展,在全基因组关联分析的框架内进行上位效应遗传位点的检测越发受到重视。文章以遗传力失踪问题为出发点,首先综述了标记-QTL连锁分析和GWAS框架下传统上位效应遗传位点的检测方法,然后对基于表型方差同质性检验和广义线性混合模型方法的上位效应统计推断以及混杂因素的处理方法进行了总结与梳理,旨在为数量性状全基因规模上位效应的相关研究提供理论参考。     

Genetics of grain yield and other agronomic characters in t'ef (Eragrostis tef Zucc Trotter). II. The triple test cross

The normal and selfed families of the triple test cross were employed to detect gene action in t'ef for grain yield and other useful agronomic characters in the breeding programme. Cultivars Kay Murri and Fesho were used as L₁ and L₂ testers, respectively. Eight randomly selected cultivars and two released varieties (DZ-01-354 and DZ-01-196) were crossed with the testers L₁, L₂ and L₃ (the F₁ of L₁ × L₂). In the case of the selfed families, 14 cultivars and two released varieties were used for crossing with the testers. The normal families were grown on an Inceptisol developed from volcanic ash whilst the selfed families were grown on a pellic Vertisol at the Debre Zeit Agricultural Research Centre, Ethiopia. The rainfall during the experimental season was 463 mm. Epistasis was detected for grain yield, yield per panicle, panicle weight, plant weight, harvest index, tiller number, panicle length, culm diameter, days to heading and days to maturity in the normal families of the triple test cross (TTC) of t'ef. Similarly the characters grain yield, yield per panicle, panicle weight, plant height, panicle length, days to heading and days to maturity showed epistasis in the selfed families of the TTC. Epistatic interaction was not important for shoot biomass and for harvest index (for the transformed data) in this family. Therefore, both the normal and selfed families of the TTC were in agreement with regard to detecting epistasis for grain yield, yield per panicle, panicle weight, panicle length, days to heading and days to maturity. Significant additive (D) and dominance (H) components were estimated for the characters in both families, although the magnitudes might have been inflated due to epistasis. The dominance component for panicle length was unimportant in both families of the TTC and as a result the additive components were not biased. In general, the additive, dominance and epistatic components were important in t'ef. Since the crop is self-fertilized only the additive and additive × additive terms are important to develop pure breeding varieties. Therefore, selection for superior segregants should start in advanced generations as homozygosity increases. This revised version was published online in July 2006 with corrections to the Cover Date.     

QTL epistatic analysis for yield components with single‐segment substitution lines in rice

Epistasis is an important genetic component in determining the phenotype of complex quantitative trait. In this article, 12 single‐locus heterozygotes and 66 double‐locus heterozygotes were developed and then were applied to assay QTL epistasis for four yield‐associated traits under two planting densities. Of 264 (66 × 4) tested interactions, 130 (49.2%) were significant at the p < .05 level. QTL with the same effect directions had higher probabilities of interactions. The negative epistasis at least included one positive effect QTL but the positive epistasis one negative QTL. The detected epistasis was sensitive to planting density. Epistasis also exhibited pleiotropic effects.     

Quantitative trait loci for grain yield and yield components in a cross between a six-rowed and a two-rowed barley

Summary The positions of quantitative trait loci (QTL) for yield and yield components were estimated using a 85-point linkage map and phenotype data from a F₁-derived doubled haploid (DH) population of barley. Yield and its components were recorded in two growing seasons. Highly significant QTL effects were found for all traits at several sites in the genome. A major portion of the QTL was found on chromosome 2. The effect of the alleles in locus v on thousand grain weight and kernels per ear explained 70–80% of the genetic variation in the traits. QTL × year interaction was found for grain yield. Several different QTL were found within the two-rowed DH lines compared to those found in the six-rowed DH lines. Epistasis between locus v and several loci for yield and yield components indicates that genes are expressed differently in the two ear types. This may explain the difficulties of selecting high yielding lines from crosses between two-rowed and six-rowed barley.Abbreviations DH doubled haploid - QTL quantitative trait locus/loci - RAPD random amplified polymorphic DNA - RFLP restriction fragment length polymorphism - T. Prentice Tystofte Prentice - V. Gold Vogelsanger Gold     

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.     

Inheritance of resistance to races 1, 2 and 5 of powdery mildew in the melon TGR-1551

The inheritance of resistance to races 1, 2 and 5 of Podosphaera xanthii in the melon TGR-1551 was studied in a cross with the susceptible cultivar 'Bola de oro'. Under artificial inoculation conditions, four phenotypic classes were defined according to the level of fungal sporulation. The segregation ratios for resistance/susceptibility observed in the different populations and the results of the progeny test indicated that resistance to races 1, 2 and 5 of P. xanthii in TGR-1551 was governed by two independent genes, one dominant and one recessive, which means that the genetic control is a dominant–recessive epistasis. This is the first time that a recessive gene that confers resistance to more than one race of powdery mildew has been identified in melon. TGR-1551 could be considered a good genetic source for the development of powdery mildew resistant breeding lines.