【目的】粒型性状是玉米百粒重的重要组成部分,并具有较强的杂种优势,鉴定玉米粒型性状的杂种优势位点,可以为粒型性状关键杂种优势位点的克隆与分子标记辅助育种提供理论依据。【方法】利用一套中国优良自交系lx9801背景的昌7-2单片段代换系为基础材料,与自交系T7296测交构建包含184个测交种的群体。2013年,在河南浚县和长葛两点对测交群体、单片段代换系群体等材料进行了田间鉴定,完全随机区组设计,3个重复,成熟后连续收获10株对粒长、粒宽、粒厚和百粒重进行考种。利用方差分析和t测验比较每个SSSL×T7296测验种单个性状与对照种T7296×lx9801的显著性差异,对玉米粒型性状的杂种优势位点进行定位。【结果】单片段代换系的两个亲本在粒型性状上表现出明显的差异,昌7-2的粒长和百粒重高于lx9801,而粒厚低于lx9801。测交群体4个籽粒性状均表现出一定的杂种优势,粒长的平均中亲优势在长葛和浚县点分别为19.32%和15.30%,粒宽的中亲优势分别为10.86%和10.07%,粒厚的中亲优势分别为6.23%和4.78%,百粒重的中亲优势分别为20.97%和25.09%。相关分析结果表明,粒长与粒宽、百粒重呈显著正相关,粒宽和粒厚与百粒重也呈显著的正相关,粒宽与粒厚呈负相关关系。在2个环境中定位了13个粒长的杂种优势位点,其中1杂种优势位点同时被检测到。粒宽定位到14个杂种优势位点,在长葛点和浚县点分别检测到1个主效的杂种优势位点。粒厚检测到25个杂种优势位点,在第2、3、7和9染色体上分别定位到1个共同的杂种优势位点。百粒重在2种环境中共检测到24个杂种优势位点,有6个杂种优势位点同时被检测到,其中在第1染色体上检测到2个共同的杂种优势位点h KW1a和h KW1b;在第7染色体上检测一个主效的杂种优势位点h KW7a,在长葛点和浚县的贡献分别为20.12%和11.03%;位于第8染?
[Objective] Kernel shape traits are important components of 100-kemel weight and show high heterosis. Identifying the heterotic loci for kernel related traits and subsequently dissecting the genetic basis architecture of heterosis for kernel related traits can provide useful information for cloning heterotic QTL and the development of elite hybrids by molecular breeding. [ Method] A set of chromosome segment substitution lines (CSSLs) population was constructed using the inbred line lx9801 as the receptor parent and the inbred line Chang7-2 as the donor parent, which was used as the martial and test with the inbred line T7296 to construct a set of 184 test hybrid population. The test population, CSSLs population as well as other materials were evaluated in the field by following three replicates in randomized complete blocks with at Changge and Xunxian locations in Henan province in 2013. Ten plants were harvested after the physiological maturity period. Then, four kernel-related traits were investigated as follows: Including kernel length (KL, mm), kernel width (KD, Mm), kernel thickness (KT, mm) and 100-kernel weight (KW, g). The heterotic loci for kernel related traits were identified through significant analysis comparing to each test hybrid and the CK T7296xlx9801 by mean of variance analysis and t test. [Result] The kernel shape traits of the two parents in the CSSLs population had obvious differences; the kernel length and 100-kernel weight of the parent Chang7-2 was higher than 1x9801, and the kemel thickness was lower lx9801. The four kernel shape traits in the test population had certain heterosis, the mid-parent heterosis of kernel length were 19.32% and 15.30% in Changge and Xunxian locations respectively, the mid-parent heterosis of kernel width were 10.86% and 10.07%, the mid-parent heterosis of kernel thickness were 6.23% and 4.78%, and the mid-parent heterosis of 100-kernel weight were 20.97% and 25.09%. The results of correlation analysis showed that kernel length expressed