我国黄淮和南方主要大豆育成品种家族产量和品质优异等位变异在系谱中遗传的研究

Inheritance of Elite Alleles of Yield and Quality Traits in the Pedigrees of Major Cultivar Families Released in Huanghuai Valleys and Southern China

以往研究育成品种间的遗传关系只能通过系谱追踪进行一般性分析,分子标记的发掘则提供了在位点及其等位变异基础上分析育成品种间遗传关系的手段。本研究在黄淮和南方190份大豆育成品种的85个SSR标记与农艺性状关联分析基础上,将其中163份品种按系谱祖先归为58-161、徐豆1号、齐黄1号、南农493-1、南农1138-2五个家族,对产量和品质性状进行优异等位变异在系谱中传承情况的分析。所涉及的最佳位点,产量9个、百粒重3个、蛋白质含量2个、脂肪含量4个,总解释率分别为91%、36%、13%和31%。每位点考查2个最优等位变异,家族系谱祖先具有各自的优异等位变异,随着育种轮次的增加在后育成品种中有丢失;在系谱祖先基础上新品种衍生过程中吸纳其他亲本,5个家族趋向共有大部分优异等位变异,但频率分布不同。5个家族的品种所含有产量最多优异等位变异数未达饱和,9个位点中最高含7个优异等位变异,平均每个品种2.23个,产量有进一步改良潜力。供试条件下高产品种平均产量是低产的2.36倍,平均优异等位变异数是低产的4.17倍,高、低产品种优异等位变异构成差异明显,但高产品种间优异等位变异构成并不相同。也有的品种高产而优异等位变异数并不多,有的品种优异等位变异较多但产量并不高。大豆育种不断从不同亲本中累积目标性状优异等位变异,同时有些也在丢失,应重视保存过时品种的优异等位变异,以备后用。

It is commonly understand that molecular markers have provided an opportunity for plant breeders to trace genetic relationship precisely among released cultivars, while it can be done only roughly through pedigree analysis. In the present study, 163 released soybean cultivars of the five major family pedigrees in Huanghuai Valleys and Southern China, with 58-161, Xudou 1, Qihuang 1, Nannong 493-1, and Nannong 1138-2 as their respective pedigree ancestor, were analyzed for transition of elite alleles of yield and quality traits in each family pedigree based on the association analysis between 85 SSR loci and agronomic traits in 190 released cultivars in the same region. Two best alleles of each of the nine, three, two and four major loci, explaining 91%, 36%, 13%, and 31% of total phenotypic variation of the four traits, respectively, were traced for their transition in the five cultivar pedigrees. It was found that each pedigree ancestor had its＇own elite alleles which transited to its progenies, but some of them might be lost during the process. The five family pedigrees tended to share all the elite alleles but with different frequency distributions due to diverse parental materials used in the pedigrees. The cultivars in the pedigrees had different number of elite alleles for yield, where the highest elite allele number contained in a cultivar was seven but not the full of 9 and the average was only 2.33, indicating great yield potential in recombination and accumulation of elite alleles for future breeding. Under the experiment conditions, the average yield of high-yielding cultivars was 2.36 times of that of low-yielding cultivars while the average elite allele number of the former was 4.17 times of that of the latter, but the composition of elite alleles among the high-yielding cultivars was quite different. On the other hand, unusual cases of some cultivars with high yield but less elite alleles and some with low yield but more elite alleles were also observed. It is suggested for breeders to conserve carefully the old cultivars for future breeding since they might have some specific elite alleles in their genome.