| Rice blast is one of the main diseases of rice caused big yield lose in rice planting area across the world. Developing blast resistance cultivars is the the most effective, economic and environment protecting way. With the progress of R-gene mapping and cloning of blast and advanced molecular breeding technology, the developing of blast resistance rice varieties has been accelerated in past years. In this research, two rice blast resistance genes Pi1 and Pi2 coming from donor parents TMQ10242 and YAQ10242 were introgressed into receptor parent R666(an elite rice restorer line) by using molecular marker-assisted selection and crossing and backcrossing technology. We got some improved strains carrying rice blast resistance genes Pi1 and Pi2. We select some rice lines which have the same agronomic traits as R666 but carrying blast resistance genes, crossed with sterile lines, such as Hua1165 S, Hua1037 S, Hua1015 S, Y58 S, at the same time we sent these to identify the resistance levels to rice blast. The results are as follows:1. We selected 14 new restore lines from R6664/YAQ10242 offspring which carrying Pi2, 3 new restore lines from R6664/TMQ10242 offspring carrying Pi1, the rice blast identification of these lines and their hybrid combinations was conducted at Yichang in 2015. The results showed that comprehensive resistance index of receptor parent R666 is 6.0, moderate susceptible to blast; eight lines’ comprehensive resistance index are 1.3 to 1.8, highly resistant to rice blast; five lines’ comprehensive resistance index are 2.3 to 2.8, resistant to rice blast; four lines’ comprehensive resistance index are 3.8 to 5.0, moderately resistance to rice blast. These showed that the rice blast resistance of the improved lines have increased significantly. Under the same conditions, 17 hybridized combinations which came from the improved restore lines crossed with Hua1165 S, the results showed that all of the 17 hybridized combinations’ comprehensive resistance index are 1.0 to 2.8, high resistance to rice blast.2. In August 2014 in Wuhan, the 17 improved restore lines were crossed with four sterile lines(Hua1165S, Hua1037 S, Hua1015 S, Y58S), we got 72 hybridized combinations, grew in Ezhou, testing the yield, main agronomic traits and grain quality, and the Fengliangyou No.4 used as the controll. The results showed that, the six combinations yield per plant were over R666 crossed with corresponding sterile lines by 2.1%、0.3%、3.0%、2.7%、6.6%、1.0%, respectively, but their growth duration were shorter, the other agronomic traits are similar. the yield per plant of six combinations were over Fengliangyou No.4 by 10.1%、8.2%、8.1%、7.9%、6.3%、0.8%, respectively. The other agronomic traits were similar, but their growth duration were longer than that of Fengliangyou No.4.3. Combining ability analysis the 17 strains materials, R666, and four sterile lines(Hua1165S, Hua 1037 S, Hua1015 S, Y58S) by using the NCⅡ design, statistics indicates that:The analysis results of combining ability for the 17 improved restore lines showed that the yield general combining ability of JQ13004-20-17-9 was best among the selected breeding lines and better than that of recipient parent R666, The yield general combining ability of JQ13004-1-9 was similar to R666, and its variance of special combining ability was increased, implying it was a better line in hybrid rice breeding program. The yield general combining ability of JQ13004-1-13 was similar to R666, but their variance of special combing ability was lower than that of R666, implying lower valuable in hybrid rice breeding program. |
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