水稻白叶枯病抗性遗传效应的组分分析

COMPONBNT ANALYSIS OF GENETIC ON RESISTANCE TO BACTERIAL BLIGHT IN RICE

从籼型水稻品种中鉴定、筛选出７个不同抗级的抗白叶枯病基因源，加入高感病标准品种ＴＮ１，作８×８完全双列杂交，按Ｈａｙｍａｎ模型进行遗传分析。结果是：在遗传方差中，加性方差占７５．２４％，显性方差占２０．３６％，上位性方差占４．２２％；广义遗传力ｈ２Ｒ＝２９７．９８％，狭义遗传力ｈ２ａ＝７３．９０％；最少加性基因数ｋ＝４，显性基因数ｋ′＝２４；具不完全正显性，所有显性座位的作用方向相一致，不同显性座位的效应可能稍有差异；遗传群体中，正效基因频率ｐ＝０．４７３，负效基因频率ｑ＝０．５２７，ｐ∶ｑ接近１∶１，但不同亲本正负效基因分布有明显差异。

A 8×8 diallel crcos of seven hsien(indica ) rice cultivars with different resistanceto bacterial blight(Xanthomonas oryzae),derived from evaluation and screening,and TN1,a high susceptible standard cultivar ,was made·Genetic analysis was conducted by Hayman 'sModel,within genetic variances,additive variance,dominance variance and epistasis var-ance are 75.42%,20.36% and 4.22%respectively. Heritability in broad sence,hR2=97.98%,while heritability in narrow sense,hN2=73.90%. Least numbers of additive gene,k=4,while numbers of dominant gene,k'=4.In other words , the resistance features in-complete positive dominance and the action direction of all dominant loci is consistent.Theeffect of different dominant loci may exist slight difference. In genetic population,the fre-quency of positive effect gens,p=0.473, while the frequency of negative effect gene,q=0.527.p:q is closely to1 :1 ,The distribution of positive and negative effect genes derivedfrom cultivars with different resistance is markedly different.