Prediction of heterosis in wheat using coefficient of parentage and RFLP-based estimates of genetic relationship
Prediction of heterosis in wheat using coefficient of parentage and RFLP-based estimates of genetic relationship
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作者：
BarbosaNeto, JF;Sorrells, ME;Cisar, G
遗传关系可以作为杂种组合相对性能的有效预测指标，用于杂交育种计划，从而减少杂交测试的时间和成本。利用41个DNA无性系对273个DNA片段进行杂交，计算亲本系数（COP），估计了112个小麦品系的亲缘关系。估计在多个地点生长的722个杂交种具有杂种优势，其中189个在1年以上的时间内进行了测试。基于限制性片段长度多态性（RFLP）的遗传距离指数平均为0.35。中亲本杂种优势为- 20% ~ 57%，高亲本杂种优势为- 22% ~ 47%。基于rflp的遗传距离估计值与COP之间的相关性不显著（-0.33）。亲本系数与各性状的杂种优势在1991年呈极显著相关，其余年份无显著相关。本研究中基于RFLPs评分的遗传距离在任何年份的测试中都与杂种优势无关。需要进一步完善基因库和新的预测方法，以便利用遗传变异进行杂交小麦改良。
Genetic relationship can be a useful predictor of the relative performance of hybrid combinations for a hybrid breeding program resulting in reduced time and cost of hybrid testing. Genetic relationships of 112 wheat (Triticum aestivum L. em. Thell.) lines were estimated using 41 DNA clones hybridizing to 273 DNA fragments and by calculating coefficient of parentage (COP). Heterosis was estimated for 722 hybrids grown in multiple locations, with 189 being tested in more than 1 year. The average RFLP (restriction fragment length polymorphism) based genetic distance index (DI) was 0.35. Midparent heterosis for grain yield ranged from -20 to 57% and high-parent heterosis from -22 to 47%. The correlation between RFLP-based estimates of genetic distance and COP was nonsignificant (-0.33). Coefficient of parentage was significantly correlated with heterosis for all traits in 1991 but not in other years. Genetic distance based on RFLPs scored in this study was not correlated with heterosis in any of the years tested. Further refinement of gene pools and new prediction methods will be required to facilitate the exploitation of genetic variability for hybrid wheat improvement.