Developing Rice Restorer Lines Resistant To Bacterial Blight, Blast And Brown Planthopper By Molecular Pyramiding

The Bacterial blight caused by Xanthomonas Oryzae PV. Oryzae Xoo, blast caused by Pyricularia grisae and brown planthopper caused by Nilaparvata lugens are main diseases and pest to be the most devastating in most rice-growing regions including China, and some country of North and South America and Africa on the world. They reduce yield and rice quality and stability of production. The creation of resistant varieties by backcross assisted markers is a method that is economical and ecological and presents no risk or problem concerning their ethical acceptability.R1005is an elite restorer line, which was widely used as male parent of CMS-system rice hybrids in Southern China. Five hybrids in which R1005was used as male parent were released in past ten years. But, these hybrids were not resistant to blast, bacterial blight and brown planthopper. In this study,75-1-127harboring Pi9and resistant against blast (BL), JYQ9008harboring Xa23and resistant against bacterial blight (BB), and B5harboring Bph14and Bph15and resistant against brown planthopper (BPH), were used as R-genes donor. R1005was used as recipient parent for improving its resistances of BL, BB and BPH. The main results are as follows:1. Six breeding restorer lines (designed as MD12086-41, MD12086-293, MD12086-352, MD12086-394, MD12086-1089and MD12086-1351) harboring four R-genes, Xa23, Pi-9, Bph14and Bph15and about50breeding restorer lines harboring two R-genes were selected by MAS, gene pyramiding and backcross.2. The results of evaluating bacterial blight resistance showed that all of six breeding lines and their derived hybrids were highly resistant to two epidemic strains (ZHE173and GD1358) of Xoo.3. The results of evaluating blast resistance under natural condition induced blast area at Yuanan and Enshi showed that the leaf blast score and panicle blast incidence of six breeding lines and their derived hybrids were lower than the recipient R1005.4. The results of evaluating brown planthopper showed that all of six breeding lines and their derived hybrids were highly resistant to brown planthopper. 5. The evaluation results of yield, rice quality and main agronomic traits of six breeding lines showed that the grain yield per plant of MD12086-293and MD12086-1089were similar to or higher than R1005. The performance of main agronomic traits and rice quality of six selected restorer lines were similar to R1005.6. The results of yield evaluation of combinations in which the selected six restorer lines were used as male parents showed that the yield of one combination, Rongfeng A/MD12086-1089, was similar to Wuyou308(CKl), the yields of nine combinations were higher than Q-You6(CK2). Two combinations, Rongfeng A/MD12086-41and Q2A/MD12086-352were selected as premising hybrids under the analyzing of yield, rice quality, growth duration and main agronomic trait performances.