大豆不同亲本正、反交F_2、F_3、BC_1F_2主茎节数遗传规律研究

为深入理解大豆主茎节数的遗传规律,提高杂交组配及选择效果,以中、美大豆品种为亲本,对正、反交F2、F3、BC1F2后代群体的主茎节数遗传规律进行了比较研究。结果表明:不同大豆亲本杂交及回交后代群体的主茎节数变异度不大,分离强度表现中等;F3主茎节数的超亲优势较F2增强,而分离强度小于F2;大豆杂交及回交早世代主茎节数的遗传与其亲本值相关,以主茎节数少的品种为母本的组合,其杂交和回交早世代群体的平均值比以主茎节数多的品种为母本的组合偏小,而分离强度偏大,反之则异然;采用主茎节数少的品种回交不利于后代群体平均节数的增加,有利于回交后代群体分离强度保持在较高水平,扩大选择空间;而采用主茎节数多的品种回交虽有利于后代群体平均节数的增加,但回交后代群体分离强度偏低,选择空间缩小。研究还表明,主茎节数在F2、F3都具有较高的广义遗传力,且差异较小,在这2个世代进行选择是有效的;杂交早世代主茎节数的广义遗传力与组合配置有关,母本主茎节数多的组合,主茎节数广义遗传力大于母本主茎节数少的组合。

Abstract： To deeply comprehend the heredity of stem nodes number and to advance crosses and selection efficiency, Comparative studies were made on genetic rules of stem node number at F2, F3 and BC2F2generations between crosses and reciprocal crosses of varieties from China and the USA. The variance coefficient of stem node number is mod- erate at F2, F3 and BC1F2 generations. Transgressive inheritance of stem node number is stronger at F3 than that at F2. But the variance coefficient is less.The inheritance of stem node number is related to the female parents at F2, F3 and BC1F2 generations. It was also found that broad heritahility are high at F2, F3 generation of crosses and reciprocal crosses, and thus excellent unit by stem node number can be selected at earlier generations. The value of broad heritability at F2, F3 is also related to the female parents.