Evaluation Of Resistance To Rice Blast, Main Agronomic Traits And Heterosis Of 78 Rice Materials Of Breeding Restorer Line

Rice blast, caused by Magnaporthe grisea (Hebert) Barr., was one of the most devastating plant diseases, infecting rice crops all over the word. Breeding and utilization of resistant cultivars was the most effective and economical way to control this disease. Screening and utilization of rice resources resistant to blast was the foundational measure to breed resistant varieties. The resistance to rice blast, main agronomic traits, grain appearance quality and milling quality of 78 rice materials of breeding restorer line were evaluated in this paper. The resistance to rice blast, main agronomic traits and heterosis of the testcross combinations from CMS-lineⅡ-32A and 78 rice materials were ecaluated. The combining ability and heritability of GR55 which was the important rice material were analysised.1. The resoult of resistance identification of 78 rice materials showed that 11 were highly resistant to both leaf blast and panicle blast,14 were medium in leaf blast and panicle blast and 20 were susceptible. GR09 and GR56 were highly resistant to rice blast, with both leaf blast and panicle of 1 scale. GR55 was also highly resistant to rice blast, with leaf blast 3 scales and panicle blast 0 scale.2. The agronomic traits of 78 rice materials of breeding restorer line were abundant genetic diversity. Day of sowing to initial heading was from 101.00 to 119.00d, plant heigh was from 92.40 to 123.80cm, spike length was from 20.66 to 29.72cm, effective panicles per plant was from 6.53 to 11.33,1000-grain weigh was from 24.89 to 40.60g, spikelets per panicle was from 112.69 to 234.99, seed density was from 4.01 to 8.38 per cm, grain weight per plant was 19.20～36.28. With grain weight per plant for main characters, the grain yields of 26 materials were above 30g and had high performance.3. The result of the roughness of 78 rice materials of breeding restorer line indicated that there were 23 materials reached the first grade of the national standards,29 reached the secend grand of the national standards and 18 was the third grand of the national standards. The result of whole paddy rate showed that 25 were the first grade of the national standards,4 were secend grand and 6 were third grand. The result of chalkiness showed that GR45, GR14, GR44 and GR41 were fisrt grand,23 were secend grand and 21 were third grand. Chalkiness degree indicated that only GR45 was first grand of national standards, GR44, GR14 and GR41 were secend grand,10 were third grand.4. The result of resistance to rice blast of F1 generation showed thatⅡ-32A/GR5,Ⅱ-32A/GR9,Ⅱ-32A/GR44,Ⅱ-32A/GR45,Ⅱ-32A/GR49 andⅡ-32A/GR53 were not heading. The resistance result of other 72 F1 generations indicated that 8 was with leaf blast 1-5 scale and panicle blast 1 scale which had high resistance.5. Compete vigor of agronomic traits of F1 combinations to Gangyou725 showed that, The range of compete vigor of the period of from sowing to heading was -4.0～8.0d. The period of from sowing to heading ofⅡ-32A/GR31,Ⅱ-32A/GR30 etc 17 combinations was shorter than Gangyou725; The competitive advantage of plant height ranged -6.0～11.2cm, there were 19 competitive were lower than Gangyou725; The range of compete vigor of panicles per plant was -3.7～1.9 panicles; The range of compete vigor of 1000-grain weight was -2.7～4.8g; The range of compete vigor of spikelet per panicle was -61.9～41.5 grain; The range of compete vigor of filled spikelet per panicle was -35.5～53.0 grain; The range of compete vigor of seed setting percentage was -52.0～20.3%; The range of compete vigor of grain yield per plant was -14.3～10.7 grain,21 combinations's range of 72 testcross F1 combinations was superiority.6. The analysis of test variance and combining ability variance showed that variance of all the traits of the block were not significant, the variance between all combinations have reached a significant level. Shuhui527 had the maximum value of combining ability of grain yield per plant among the six restorer parents. Comprehensive analysis of Shuhui527 and GR55 were the ideal restorer parents while the ChuanguA was the ideal CMS parents. Obtained by the analysis of specific combining ability, nonadditive genetic effects of agronomic characters were diverse while there was diversity in gene interaction. Based on the results of specific combining ability effect value,46A×GR55 was the best hybrid combination for its maximum grain yield per plant 30.458g while the 4A×GR55 also performed well.