小麦亲本间分子遗传距离与F1杂种优势的相关性分析

为了探讨利用小麦亲本间分子遗传距离预测F1杂种优势的可行性，以河南省8个不同类型的小麦品种（系）为材料，分别于2003年和2004年按不完全双列杂交组配28个组合，分析与产量相关的9个性状的F1杂种优势。分别选用均匀分布于小麦21条染色体上的287对SSR引物和33个二核苷酸重复ISSR引物，计算8个亲本间的分子遗传距离．进而分析亲本间分子遗传距离与F1杂种优势表现的相关性。结果表明，SSR和ISSR两种标记估算的遗传距离间相关极显著（相关系数为0．832），表明用两种分子标记对小麦品种进行遗传差异分析的结果是一致的。除株高外，利用两种分子标记计算的亲本间分子遗传距离与F1杂种优势在全部28个组合中相关不显著，而在12个极端组合中相关系数得到较大提高，并在株高、主茎千粒重和千粒重3个性状上相关达到显著或极显著水平，且两年的研究结果一致。这说明亲本间分子遗传距离与F1杂种优势的相关性与材料的选择有关。因此认为利用小麦亲本间的SSR和ISSR遗传距离预测F1的杂种优势还需进一步研究。

Relationship between the Genetic Distances Based on Molecular Markers and Heterosis in Hybrid Wheat

Heterosis is an important approaches to increase crop yield and improve quality, and the quick and accurate method to predict heterosis is helpful to select good hybrids with strong heterosis. Eight wheat parents with different characters were crossed in 2003 and 2004 in an incomplete dialed mating system in order to evaluate the heterosis of the 9 characters. The molecular genetic distances of 8 parents were estimated by 287 pairs of SSR and 33 ISSR primers. The relationship between the genetic distances based on SSR and ISSR markers and heterosis of wheat was investigated. The results showed that there was very significant correlation between the two kinds of genetic distances. Except for plant height, no significant correlation was found between genetic distances and heterosis of other agronomic traits in all the 28 crosses. For the 12 extreme crosses, the correlation was improved, correlations between genetic distances and heterosis of agronomic traits were significant or very significant in plant height, 1000-grain weight of the culm ear and 1000-grain weight. The results in the two years were similar. Therefore, the correlation was affected by the parents used, and more studies should he carried for the relationship between the SSR and ISSR genetic distance and heterosis of wheat.