对洛夫林10小麦品种作为叶锈病抗源的评价

对洛夫林10小麦品种能致病的叶锈菌小种群在不断上升,给抗病育种带来了威胁。本试验选用的小麦品种有目前参加品比、区试和生产上推广的53个优良品种,其中38个其亲本是以洛夫林10为抗源。用对洛夫林10能致病的7个优势小种,和对洛夫林10不能致病的4个优势小种与这些品种进行相互作用研究。结果表明,以洛夫林10为抗源所培育的品种对“洛10”小种不是都感染的,它们与叶锈菌的亲和率为22％,不以洛夫林为抗源的品种与叶锈菌的亲和率则为42％。另外还有4个以洛夫林10为抗源的品种对参试的所有小种都抵抗,说明洛夫林10这个品种作为叶锈病抗源,目前在生产上对叶锈病的防治还有相当的价值。然而,研究也表明,除了“洛10”小种群外,有些非“洛10”小种对以洛夫林10为抗源的品种也能致病,这说明抗性基因在一定的遗传背景中起作用,而在另一些背景中不一定起作用。为此,应避免抗源单一化,并加强遗传学研究,大力筛选新抗源,使抗病性建立在抗源多样化的稳固基础之上。

The Evaluation of the Value of Lovrin 10 as the Source of Resistance to Leaf Rust of Wheat

The increase of the frequency of occurrence and extension in geographic distribution of races virulent to wheat cultivar Lovrin 10 threatened the breeding for resistance. The interaction of 53 promising wheat cultivars and 11 prevalent races of Puccinia recondita f. sp. tritici was studied. Among the 53 cultivars, 38 have Lovrin 10 as one of the parents, and among the llraces, 7are virulent to Lovrin 10, the other 4 are avirulent. The result showed that riot all the cultivars derived from Lovrin 10. as the resistant parent were susceptible to the races virulent to Lovrin 10. The rate of compactibility between cultivars and races was 22% while that between the cultivars which did not have Lovrin 10 as the parent and the same races was 42%. Besides, 4 cultivars with Lovrin 10 as one of parents were resistant to all the races tested. All these facts indicated that Lovrin 10 was still higly valuable as a source of resistance against the leaf rust of wheat regardless the existance of virulent races. However, the results of our study also showed thal besides the races which were virulent to Lovrin 10, there were also races avirulent to Lovrin 10 but virulent to its offsprings. This indicated that a gene of resistance might function In one background, but might not be so in another background. The authors emphasized the imporance of genetic study in breeding program and screening for new sources of resistance so as to realize the diversification of resistance.