| Rice blast is one of the important diseases affect rice production,the most economic and effective measures to improve the rice blast disease resistance is to cultivate and use resistant varieties reasonably.Fengliangyou No.1 is a rice combination with high yield and good quality which has been largely planted in agricultural production,but it was poor resistance to rice blast that highly sensitive to leaf blast and panicle blast.It has obtained 12 modified strain which carry the rice blast resistance genes Pi9 and the agronomic traits near recipient parent R2106 through many times back-cross and self-cross combined with the molecular marker assisted selection after its hybridization by using paternal R2106 of Fengliangyou No.1 as recipient and transmigrate parent and 75-1-129 as donor parent.We have studied the resistance ability to rice blast,the main agronomic traits and the rice quality performance for these 12 modified strains and their combinations on these basis above.We also analyzed the high yield stability for hybrid combinations of these 12 modified strain.The main results were as follows:1)PCR detection results show that these 12 modified strains can amplify specific bands,it can determine that Pi-9 gene has been integrated into them.The hybrid combinations of these 12 modified strains combined with Guangzhan 63 S were all amplify specific bands of Pi9 gene.Pi9 gene can be inherited stably in the offspring.2)The leaf blast of these 12 modified strains were 1 to 3 rank and the disease-resistant index is basically under 10% that its resistance level were resistance(R)or middle resistance(MR).And its panicle neck blast concentrated in 5 to7 rank and the disease-resistant index were under 30% that its resistance level were middle sensitive(MS)or high sensitive(HS).The leaf blast of its combinations were 3to 5 rank and the disease-resistant index is basically under 30% that the resistance level were middle resistance(MR)or middle sensitive(MS).And its panicle neck blast concentrated in 5 to 7 rank and the disease-resistant index were under 40% that its resistance level were middle sensitive(MS)or high sensitive(HS)too.The blast resistance of these 12 modified strains and its combinations,even leaf blast or panicleneck blast were superior to contrast.Rice blast resistance genes Pi9 have been expressed defectively in modified strains and its combinations.3)The difference of main agronomic characters of these 12 modified strains and their combination was not significant to CK.Because of many times back-cross and self-cross with purposely selection,the main agronomic traits in the majority of materials and the combinations corresponding has same to their parent or the original combination,even better than the parents or the original combination.4)The brown rice rate and the head milled rice rate of these 12 modified strains and their combination is better than that of CK,while the chalky grain percent and chalkiness degree is inferior to CK.There were irregular for other rice quality traits.There were only four modified strains whose rice quality reach to optimal secondary grade.The four modified strains were HK7001,HK7005,HK7007 and HK7009.Other modified strains are optimal level 3.There were only two combinations of modified strains combined with Guangzhan 63 S,which were Guangzhan63S×HK7005 and Guangzhan 63S×HK7007 whose rice quality reach to optimal secondary grade.The rice quality of Guangzhan 63 S x HK7010 is relatively poor,is just in 4 level,other combinations are optimal level 3,too.The import of Pi-9 gene can cause variation of rice quality.As the chalky grain percent and the chalkiness degree were droped,rice quality of these 12 modified strains and their combination overall decline than CK.5)The high yield stability of hybrid combinations of these 12 modified strains combined with Guangzhan 63 S have different.The high yield stability of two combinations,Guangzhan 63S×HK7007 and Guangzhan 63S×HK7005 is the best.The average yield of these two combinations were 587.88 kg / 667m2 and 580.75 kg /667m2 respectively which were 2.34% and 1.14% higher than CK and the high stability coefficient(HSCi)were 90.17%,and 89.90%.The performance of the rest combinations is poor which the HSCi were less than CK,but the production was reduced not by much.6)Combined with the ability of resistance to rice blast,the performance of main agronomic traits,the rice quality performance as well as the high yield stability ofcombinations,we found that the two modified strains of R2106 with Pi9 gene which were HK7005 and HK7007 have been stabled in agronomic traits and have strong resistance to rice blast and good rice quality,the high yield stability of their combinations were good too.So HK7005 and HK7007 can be directly used for agricultural production or used as breeding resistant parent material in the middle. |
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