两系法籼粳亚种间杂种一代优势与亲本遗传差异关系的研究

A STUDY ON THE RELATION BETWEEN THE HETEROSIS AND THE GENETIC DIVERGENCE OF THE PARENTS IN TWO-LINE HYBRIDS BETWEEN INDICA AND JAPONICA RICE

以遗传力较高且与产量密切相关的性状，以及反映籼粳稻遗传差异的部分籼粳分类性状，估测亲本间遗传距离。同时研究了代表双亲遗传差异的遗传距离与籼粳亚种间杂种一代优势的关系。结果表明：随着亲本间遗传距离增大，亚种间Ｆ１的株高、播种至抽穗日数、穗长、每穗颖花数、每穗实粒数和单株草重显著增加；在广亲和基因参预下，随着亲本间遗传距离增大，亚种间Ｆ１的千粒重、结实率和充实系数等结实特性变差但并不严重，遗传距离较大的亚种间Ｆ１平均单株粒重优势显著大于品种间Ｆ１，但遗传距离与亚种间Ｆ１，单株粒重优势的相关系数（－０．０１９）不显著。本文还就遗传距离在预测预报籼粳亚种间杂种一代优势方面的应用进行了讨论。

The genetic divergence of the parents of intersubspecific hybrids was estimatedby genetic distance involving characters with greater heribility and some classification chara-cters of cheng's Index,On the background of wide compatibility between Indica and Japonicasubspecies,the relation between the heterosis and the genetic distance between the male andfemale was studied.The main results are as follows:(1)In such characters as paniclelength. number of spikelets and filled grains per panicle and straw weight per plant,the he-terosis of F1 hybrids between Indica and Japonica increased significantly with the enlarging ofthe genetic distance between the male and female,and was significantly greater than that ofintervarietal hybrids.(2)Setting characters of F1 hybrids between Indica and Japonica includ-ing percentage of seed setting,filled coefficient and weight of 1000 grains became worse butnot severe with the enlarging of the genetic distance of the parents.(3)The transgressivevigor of plant height and number of days from seedling to heading compared to the males ofF1 hybrids between Indica and Japonica increased significantly with the enlarging of the ge-netic distance between the male and female。The application of genetic distance between theparents of intersubspecific hybrids to predicting the heterosis is also discussed。