一个小麦—中间偃麦草异代换系抗条锈病的遗传研究

Genetic Study on Stripe Rust Resistance of a Wheat-ThinopyronIntermedium Substitution Line

利用缺体回交法 ,以阿勃 3D缺体为母本、中 4 为父本培育出的小麦—中间偃麦草异代换系 N90 2 5 - 3- 3-2 - 1- 1在形态学和细胞学上已基本稳定 ,染色体构型为 2 n=4 2 =2 1″,测交杂种 F1 减数分裂中期 I染色体构型为 2 n=2 0″+2 '。该系对目前的条锈病流行小种和新小种均表现高抗至免疫 ,抗性来自中间偃麦草。为进一步研究该系的条锈病抗性遗传规律 ,以对条中 32感染的小偃 6号、中国春和阿勃分别与其杂交 ,F1 套袋自交 ,F2 代调查统计并分析其抗性分离情况。χ2 符合性测验结果表明 :小麦—偃麦草异代换系 N90 2 5 - 3- 3- 2 - 1- 1的后代植株对条中 32的抗性以3∶ 1分离 ,即表明该代换系对条中 32的抗性由一对完全显性等位基因控制。

A wheat Th. intermedium substitution line 'N9025 3 3 2 1 1' was produced by back crossing Abbondanza 3D nullisomic line as female with Zhong 4 as male parent. This new line, chromosome configuration 2n=42=21″, was stripe rust resistance with stable morphological and cytological character. The test crossing F 1 showed that chromosome configuration was 2n=20″+2' at metaphase I . To study the genetic behavour of the substitution line resistance to stripe rust, the cross of the resistance line to stripe rust was made with susceptible lines Xiaoyan 6, Chinese Spring and Abbondanza . The results showed the segregation in F 2 was 3∶1, in other words, the resistant gene of wheat Th. intermedium substitution line to Tiaozhong 32 was a single complete dominant gene.