水稻品种抗瘟遗传多样性分析及其应用

以水稻的Xa21基因中富含亮氨酸重复区域（leucine-rich repeat regions）设计的XLRR for（CCGTTGGACAGGAAGGAG）与XLRR rev（CCCATAGACCGGACTGTT）为引物,通过PCR扩增、聚丙烯酰胺凝胶电泳和银染检测,进行了江西省水稻主栽品种和地方资源品种的抗病基因类似序列（resistance gene analogue,RGA）分析.结果表明,水稻抗病基因类似序列类型丰富,供试的23个品种的RGA-PCR指纹聚类后,当以欧氏距离4.5划分时,可分为6个遗传相似组.同一遗传相似组内的品种,在品种的特性上,有较强的相似性,如第二组,由两个品种大禾谷和长粒糯组成,它们均为高秆的地方优质老品种,生产上均较感稻瘟病.烂蔸糯和流稻糯两个糯稻品种,属同一遗传相似组.当以欧氏距离5.0划分时,可分为2个遗传相似组,其中一组包括圆粒糯、大禾谷、长粒糯等江西三个地方老品种和巴西陆稻.主栽品种汕优63、两优培九等与烂蔸糯、圆粒糯等优质地方老品种,遗传距离较远.田间试验表明,遗传背景差异较大的品种混合间栽,对稻瘟病平均防效达91.98%～95.68%.

Genetic analysis of diversity of rice resistance to Magnaporthe grisea and its use for rice blast control

The genetic diversity of blast rice resistance of the rice commercial and local resource cultivars in Jiangxi Province were studied using resistance gene analogue (RGA) based on resistance gene conserved sequences. The RGA analysis for 23 cultivars was proceeded by the PCR amplification using the primers XLRR for/ XLRR rev designed based on the resistance gene Xa21 for Xanthomonas oryzae pv. oryzae. The results showed that rice cultivars were genetically highly diverse. All the cultivars were divided into 6 lineages according to the DNA band data at the lineage distance of 4.5, and divided into 2 lineages at the lineage distance of 5. Field experiments of mixed_and pure-planting of four rice varieties, representing hybrid varieties (Shanyou 63 and Liangyoupeijiu) and traditional high-quality varieties (Landounuo and Yuanlinuo), were conducted based on the differences in their genetic backgrounds. The mixed-planting of the hybrid rice and traditional high-quality rice varieties had a significant effect on the occurrence of the rice blast, particularly for the highly susceptible traditional varieties, with significant decrease in incidence and disease index and 91.98%-95.68% of control efficiency. This suggests that appropriate mixed-planting of rice varieties with different genetic backgrounds is an effective approach for rice blast control.