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穗部性状与产量密切相关,因此对其进行遗传剖析可为玉米高产育种提供理论基础,尤其是对干旱胁迫下的稳产有重要意义。本研究以玉米骨干亲本黄早四分别与自交系掖478和齐319进行杂交,构建了两套F2:3群体(分别记为Y/H和Q/H)。在正常水分灌溉和干旱胁迫下对穗长、穗粗、轴粗、穗行数、行粒数、穗粒重和穗重等7个穗部性状进行了表型鉴定,采用基于混合线性模型的单环境分析和相同处理水平的联合分析方法进行了QTL分析。结果表明,在干旱胁迫下,2个群体的亲本及F2:3家系的各性状值均低于正常水分条件,且穗粒重与穗长、穗重、穗粗呈正相关。在干旱胁迫下和正常水分条件下,通过两种检测方法共定位到75个玉米穗部性状QTL,其中Y/H群体共定位了20个QTL,分布在第1、第2、第5、第6、第7、第10染色体上;Q/H群体共定位了55个QTL,分布在第2、第3、第4、第5、第6、第7、第9、第10染色体上;但是在干旱条件下两群体分别只检测到4个和19个QTL,明显低于正常水分条件下检测到的QTL数目。通过联合分析只检测到3个QTL与环境发生显著互作和6对QTL存在上位性互作效应,说明玉米穗部性状的遗传基础较为复杂。同时还发现,Y/H群体在正常灌溉与干旱条件下检测到2个一致性的QTL,分别是qKRE1-5-1和qKRE1-7-1,对表型变异解释的变化范围是6.15%~19.48%;Q/H群体检测到3个一致性QTL,分别是qKRE2-5-1、qGW2-10-1和qKRE2-3-1,对表型变异解释的变化范围是7.14%~16.65%,说明这些QTL受环境影响较小,能够稳定遗传,可以作为分子标记辅助选择的候选区间应用于玉米穗部性状抗旱性改良。
Ear traits and yield are closely related, so its genetic analysis can provide theoretical basis for high yield breeding of maize, especially for the stable yield under drought stress. In this study, two F2: 3 populations (denoted as Y / H and Q / H, respectively) were crossed with Huangzao 4, a maize parent, with inbred lines Ye 478 and Qi 319, respectively. Under normal irrigation and drought stress, seven panicle traits such as panicle length, panicle diameter, shank diameter, panicle number, grain number per panicle, panicle grain weight and panicle weight were identified. Based on the mixed linear model Single-environment analysis and the same level of the joint analysis of the method of QTL analysis. The results showed that under drought stress, the traits of parents and F2: 3 lines of two populations were lower than those of normal water condition, and the grain weight was positively correlated with the ear length, ear weight and ear diameter. Under drought stress and normal water conditions, QTLs for total ear traits of 75 maize cultivars were mapped by two methods, of which 20 QTLs were located in the first, second, fifth, 6, 7 and 10; QTLs co-localized 55 QTLs on the 2nd, 3rd, 4th, 5th, 6th, 7th, 9th and 10th chromosomes; however, Only 4 and 19 QTLs were detected in the two populations under drought conditions, which was significantly lower than the number of QTLs detected under normal water conditions. Only three QTLs were found to interact with the environment and six to QTLs through the joint analysis, indicating that the genetic basis of maize ear traits is complex. At the same time, we also found that two QTLs were detected in Y / H population under normal irrigation and drought conditions, namely qKRE1-5-1 and qKRE1-7-1, respectively. The range of variation of phenotypic variation was 6.15% 19.48%. QTLs for QTLs detected three identical QTLs, qKRE2-5-1, qGW2-10-1 and qKRE2-3-1, respectively. The range of variation for phenotypic variation was 7.14% -16.65% These results indicated that these QTLs were less affected by the environment and could be inherited stably. These QTLs could be used as candidates for marker-assisted selection in drought resistance improvement of maize ear traits.