应用群体改良法选育高产优质抗病油菜新品种

Breeding of high yield,double low and disease resistant rapeseed cultivars by population improvement

为了探究轮回选择在油菜品种群体改良中的作用,利用具有高产、双低、抗病等优异性状的种质材料为育种亲本,以显性细胞核雄性不育基因为桥梁,构建了一个随机交配轮回选择群体。针对群体的产量、品质、抗病性等性状进行了多次轮回选择,结果表明经过6轮选择后,群体的主要性状得到改良,产量增加11.3%,每轮遗传增益为1.88%;芥酸和硫苷含量每轮遗传增益达到10.12%和6.37%,改良效果明显;但菌核病的抗性改良效果不明显。经过多轮选择后群体的遗传离散度仍然较高(0.338 3～0.377 7),表明遗传多样性并没有明显下降。从不同轮次群体中选择优异单株,经系谱选择后育成了中双5号、中双6号和中双10号等优良品种,在生产上应用广泛,表明轮回选择在油菜品种改良方面具有巨大潜力。

To study the effectiveness of recurrent selection in population improvement of rapeseed variety,a recurrent selection population was constructed by mixing several germplasm populations with high-yield,double-low and disease-resistant characteristics,using dominant genic male sterile line as a bridge for random mating.This recurrent population was then subjected to consecutive selections mainly on yield,quality and Sclerotinia stem rot resistance.Results showed that,after 6 selection cycles on the population,seed yield increased by 11.3% with a genetic gain of 1.88% per cycle.Except for stem rot resistance,obvious genetic improvements were found in erucic acid and glucosinolates contents,with a respective genetic gain of 10.12% and 6.37%.The population genetic dispersion was stable and high（from 0.338 3 to 0.377 7）,indicating no obvious penalty on genetic diversity after several cycles of selection.Ideal fertile plants identified in different generations were further developed into breeding lines by pedigree selection method.A number of new cultivars（i.e.Zhongshuang 5,Zhongshuang 6 and Zhongshuang 10） had been released and widely distributed,indicating that the recurrent selection is very useful to improve rapeseed population.