从加拿大大豆系谱分析谈大豆产量育种

EVALUATION YIELD BREEDING OF SOYBEAN FROM THE PEDIGREE ANALYSES IN CANADA

利用来自加拿大四个时期的130个大豆推广品种的系谱及遗传数据作为本文分析研究的对象。分析结果表明,全部亲本最终都是来源于38个原始亲本;四个时期新基因型的进入,呈一个双峰曲线,但新的基因型在每个时期都进入了推广品种的核心部分。原始核心基因库经过四个时期,随着累积遗传贡献的减少,在系谱中出现的频率却增加。一个高产品种,必须要有一个不同形式平均占66.3％原始核心基因库的核心基因型,以保持它高产的稳定性。聚类分析表明,不同时期都出现了相似的组,有以原始核心基因库为主的大组,有正在改良中的中等组,及新基因型掺入的单组。这些组的作用与活动促进了整个加拿大大豆的遗传进展,改良中的中等组在以后的年代有可能成为具有最大稳定性大组中一个新的亚组,单组在以后年代里有可能成为改良的中等组。 以上结果也表明了大豆产量育种,必须要有一个核心基因群的骨架,即原始核心基因库。在这基础上进一步掺入新的高产基因,才有可能获得高产的目的。原始核心基因库中的核心基因型在高产品种内可以有不同的形式。聚类分析中的不同组具有不同的遗传背景。优良品种都是来自不同组间的杂交,以组间的遗传差异来配制组合,能增加一定程度的优良组合成功率。新的高产基因应用的主要问题是高产基因的改良,实际?

The pedigrees of 130 Canadian soybean cultivars during four periods were studied. The result shows, all parents came from 38 ancestral lines; the new genotypes during four periods came in the nuclear part as a curve line. 5 ancestral lines which were the highest genetic contribution in the nuclear gene-pool appeared the increase of frequency of presence in pedigrees as the dropped of cumulative genetic contribution. A higher yield variety needs average 66. 3% ancestral nuclear genes of different forms in the cultivars. So it could keep the stability of high yield. The classification analyses shows, the similar groups were appeared in the different period, such as large group which had most nuclear genes; medium group which was improved and single group which he new genotypes were came in. The function and action of these groups formed genetic improvement of Canadian soybce n. The medium group could become a new sub -group in the h rgest group which was the higlest stabile and single group would become medium group or sub group.The soybean yield breeding needs a from of nuclear genepool and combined a few new genes of high yield. The nuclear genotypes were different forms in the high yield varieties. Different groups in classification analyses were different genetic backgroud. The best variety was from the crossing between the different groups or sub groups. Also it can get success depended on genetic variance on the origin. The main problem of new high yield gene is improvement of stabile high yield gene, also the process is the gene cumulation.