Postulation of Seedlings Resistance Genes to Yellow Rust in Commercial Wheat Cultivars from Yunnan Province in China

The objective of this study was to characterize yellow （stripe） rust resistance gene（s） in 52 commercial wheat cultivars from Yunnan Province in China, and to provide information for their rational deployment in field. Seedlings of wheat cultivars were inoculated with 25 differential isolates ofPuccinia striiformis from foreign and home to postulate resistance genes to yellow rust, and then validated by pedigree. There were 10 probable resistance genes characterized in these cultivars, in which, Yr9 was most commonly postulated to be present in thirteen cultivars. Yr21, the second, was present in four cultivars. Yr8, the third, were present in three cultivars. Yr6, Yrl 7 and Yr26, the fourth, was present in two cultivars respectively. The other gene（s） such as, Yr2＋YrA, Yr7 and Yr27, were only present in single cultivar（s）; unknown gene（s） or gene（s） combination（s） were present in 22 cultivars. One cultivar （Yunmai 42） had no resistance gene tested in this study. Cultivars such as Yunmai 52, Mian 1971-98, Kunmai 4, and Yunmai 56 carried effective genes and can be popularized mainly; Yr9 should be planted with other Yr genes. In the meantime other effective genes should be introduced to realize gene diversity for controlling wheat yellow rust. Yunmai 42 should be reduced to avoid rust breakout. Unknown gene cultivars should be utilized and be researched deeply.

两种小麦根尖染色体制备方法比较与优化

为了获得小麦根尖细胞染色体的优良制片,清晰观测到小麦染色体,以Taichung 29、中国春、中4的根尖为材料,通过时间、染色、解离和制片4个方面对常规方法和酶解法进行比较,并且在这4个方面的一些细节方面进行了优化,使得在显微镜下能清晰地数出小麦染色体的数目。常规方法整体操作时间较长达到7d,解离程度控制较精细,需要严格把控解离时间,并且对染色的时间长短要求比较严格,更需要在压片过程中严格控制力度单张玻片进行压制;而酶解法无须染色而且时间较短大约4~5d,酶解过程较易控制并且只需要对根尖捣碎不需要进行压片,控制相对容易很多,一次可进行大量制片。对比2种制片方法可以发现酶解法比较适合进行大量染色体制片。