Huang Ting-You, Li Shi-Gui, Wang Yu-Ping, Li Han-Yun
Rice Research Institute of Sichuan Agricultural University, ChengDu 611130, China.
Sheng Wu Gong Cheng Xue Bao. 2003 Mar;19(2):153-7.
'Shuhui527' is a promising restorer line bred by Rice Research Institute of Sichuan Agricultural University in recent years. However, this line is susceptible to Bacterial Blight (BB), which limits its use. The IRBB60, from the International Rice Research Institute (IRRI), contains dominant genes Xa21 and Xa4 conferring resistance to BB. The objective of this study is to improve the BB resistance of 'Shuhui527' by introgressing Xa21 and Xa4, the two broad-spectrum BB resistance genes, into 'Shuhui527' with IRBB60 as the donor, pTA248 and MP12, linking tightly with Xa21 and Xa4 respectively as DNA markers. BC1 F1 progenies of (Shuhui527 x IRBB60), containing Xa21 and Xa4 identified using PCR screening and with agronomic traits including plant type, grain type and days to heading etc similar to those of 'Shuhui527', were subsequently backcrossed to 'Shuhui527' and self-pollinated to generate BC2 F1 and BC1 F2 . The BC3 F1 and BC3 F2 were subsequently developed using the same approach. Among the 20 BC3 F2 plants, homozygous Xa21 and Xa4,10 plants were the most similar to 'Shuhui527' in the agronomic traits, and were screened using 120 pairs SSR and 100 pairs RAPD markers. Based on the results of the background screening and the performance of the agronomic traits, 5 plants were identified as improved-'Shuhui527' and designated as 527R-5, 527R-6, 527R-8, 527R-9 and 527R-10. The improved-' Shuhui527' lines expressed high resistance to Xanthomonas oryzae pv . oryzae (Xoo) stains C I - C VII, P1 and P6. The evaluation of the polymorphisms and selection accuracies of pTA248 and MP12 demonstrated that the polymorphisms of the two markers were obvious and co-dominant and the accuracies were more than 97% and 83% respectively, indicating the two markers are good for Xa21 and Xa4 in Molecular Marker-assisted Selection.
“蜀恢527”是四川农业大学水稻研究所近年来培育出的一个很有潜力的恢复系。然而，该品系对白叶枯病敏感，这限制了它的应用。国际水稻研究所（IRRI）的IRBB60含有赋予对白叶枯病抗性的显性基因Xa21和Xa4。本研究的目的是以IRBB60为供体，将两个广谱抗白叶枯病基因Xa21和Xa4导入“蜀恢527”，从而提高其对白叶枯病的抗性，分别与Xa21和Xa4紧密连锁的pTA248和MP12作为DNA标记。（蜀恢527×IRBB60）的BC1 F1代，通过PCR筛选鉴定含有Xa21和Xa4，且其农艺性状如株型、粒型和抽穗天数等与“蜀恢527”相似，随后与“蜀恢527”回交并自交，以产生BC2 F1和BC1 F2。随后采用相同方法培育出BC3 F1和BC3 F2。在20株BC3 F2植株中，10株同时纯合Xa21和Xa4，其农艺性状与“蜀恢527”最为相似，并用120对SSR标记和100对RAPD标记进行筛选。根据背景筛选结果和农艺性状表现，鉴定出5株改良“蜀恢527”，分别命名为527R - 5、527R - 6、527R - 8、527R - 9和527R - 10。改良后的“蜀恢527”品系对稻黄单胞菌水稻致病变种（Xoo）菌株C I - C VII、P1和P6表现出高抗性。对pTA248和MP12的多态性及选择准确性的评估表明，这两个标记的多态性明显且为共显性，准确性分别超过97%和83%，表明这两个标记在分子标记辅助选择中对Xa21和Xa4具有良好的适用性。
