Effect of the inbreeding depression in progeny fitness of runner bean (Phaseolus coccineus L.) and it is implications for breeding
Effect of the inbreeding depression in progeny fitness of runner bean (Phaseolus coccineus L.) and it is implications for breeding
复制标题
DOI：
10.1007/s10681-014-1177-2
复制
发表时间：
2014-12-01
期刊：
影响因子：
1.9
通讯作者：
Santalla, Marta
中科院分区：
文献类型：
--
作者：
Gonzalez, Ana M.;De Ron, Antonio M.;Santalla, Marta
尽管近交抑制率 (ID) 较高，但自交水平适中，使得红花菜豆成为豆科植物混合交配生殖生物学研究的绝佳模型。这项工作通过七个花菜豆群体的自交世代来评估不同植物生长阶段的 ID 变异程度和一致性。在先前的隔离繁殖后，在隔离的温室中对田间收集的种群进行人工授粉，历经五代以产生后代。比较了各世代对种子萌发、开花存活率以及种子重量和产量的近交效应（δ）。利用35个多态性微卫星位点估计了创始种群的异交率以及种群和世代水平的遗传变异和赖特ID。使用不同的离群值测试对世代和群体中的中性微卫星位点进行分析，以确定与近交适应直接相关的位点。我们的研究揭示了与混合交配系统一致的遗传多样性模式（H（e）= 0.36）和异交率（范围从24％到44％）。自花授粉程序显着影响发芽率和成活率、产量，并在较小程度上影响种子重量。对 Phytozome 数据库进行 BLAST 搜索时，三个位点对与胚胎发育相关的基因有显着影响。结果显示，不同植物生长阶段和种群的增量普遍不一致，表明不同的有害位点在不同阶段发挥作用。近亲繁殖往往会清除个体中有害的隐性等位基因，以减少 ID。种群内个体之间的变异可能导致 ID 水平较低的近交谱系的发展。经过多代自花授粉的几个品系在几乎所有基因位点上都变得纯合，并产生了真正育种后代的统一群体和可接受的性能。
Moderate levels of selfing despite high inbreeding depression (ID) make runner bean an excellent model for mixed-mating reproductive biology studies in legumes. This work assesses the extent of the ID variation and consistency at different plant growth stages through selfing generations in seven runner bean populations. Field-collected populations after previous isolated multiplication were hand-pollinated in an isolated greenhouse during five generations to produce progeny. Generations were compared for inbreeding effects (delta) on seed germination, survival to flower, and seed weight and yield. The outcrossing rates of the founder populations and the genetic variation and Wright's ID at the population and generation level were estimated by using 35 polymorphic microsatellite loci. Neutral microsatellite loci were analyzed through generations and populations using different outlier tests to identify loci directly associated with adaptation to inbreeding. Our study revealed patterns of genetic diversity (H (e) = 0.36) and outcrossing rates (ranged from 24 to 44 %) that are consistent with a mixed-mating system. Selfing-pollination procedure significantly affected germination and survival rates, yield, and to a lesser extent seed weight. Three loci had significant hits to genes related to embryonic development when performing BLAST searches to Phytozome database. Results showed a general inconsistency in delta across plant growth stages and populations, suggesting that different deleterious loci are acting at different stages. Inbreeding tended to purge individuals of deleterious recessive alleles to reduce ID. Variation among individuals within populations may lead to the development of inbreeding lineages with lower levels of ID. Several lines that have been self-pollinated for many generations became homozygous at almost all gene loci and produced a uniform population of true breeding progeny and acceptable performance.