Abstract: A major problem in F₁ hybrid seed production in rice is low levels of seed set on cytoplasmic male sterile lines. One of the approaches towards solving this problem is breed- ing for well-exserted stigmas to enhance outcrossing. In this research, we screened part of the African rice germplasm collections and breeding materials of the International Institute of Tropical Agriculture (IITA),Ibadan,Nigeria to identify lines with exceptional stigma exsertion (SE). A total of 2065 lines were examined, including 1787 Oryza sativa, 184 O. glaberrima, 66 O. barthii, 11 O. punctata, 10 O. stapfii, and 7 O. longistaminata. Of these, 1, 55, 35, 100, 20, and 86% respectively, were found to have a high degree of stigma exsertion. The 18 varieties and lines Of O. sativa were found to have exceptional stigma exsertion.The results indicate a greater probability of success in finding SE among related Oryza species and in landrace collections of O. sativa than in advanced breeding lines of O. sativa.

Key words: Oryza, Germplasm resource, Stigma exsertion

摘要： 为筛选柱头高度外露的稻种资源用于培育柱头外露率高的新雄性不育系,提高杂交稻制种产量,我们在位于尼日利亚伊巴丹市的国际热带农业研究所对非洲稻种资源,包括二个栽培种、三个野生种及一个杂草类型,共2065份种质进行柱头外露性状的观察。结果表明。每穗柱头外露率高(≥%)的种质的百分数从高到低依次为:斑点野生稻(100%)>长药野生稻(85.7%)>非洲栽培稻(54.9%).>巴蒂野生稻(34.8%)>杂草型 stapfii(20%)>亚洲栽培稻(1%)。在1787份亚洲栽培稻中筛选出18个柱头高度外露的种质可考虑作为培育异交率高的水稻雄性不育系的亲本。本文还分析讨论了柱头外露种质的遗传及其地理分布。

关键词: 稻属, 种质资源, 柱头外露