Study On Improvement Of Rice Blast Resistance By Using Molecular Marker-assisted Selection

The use of blast resistance genes in rice blast resistance is an effective way of enhancement of food security played an important role.Increase parental resistance to rice blast conducive to the application and promotion of a strong combination of advantages.In this experiment,the rice blast resistance genes Pi-d1 and Pi-kh were used to improve five restorer lines with poor resistance to rice blast.Through the introduction of disease-resistance genes through hybridization,selection and self-stabilization of genetic traits,selection of target genes using molecular markers closely linked to resistance genes during breeding,and field identification of the final improved restorer lines,agronomic traits,and heterosis identification with the group,in order to improve the recovery system was evaluated.The main findings are as follows:1.Select the target gene closely linked with good polymorphic markers RM224 and RM262 between the parents,and thus obtained having tow disease-resistant pure lines TR2,TR4 with Pi-kh gene resistant.And four disease-resistant pure lines DR3,DR4-1,DR4-2,DR1 with Pi-d1 resistance genes.2.Through field identification,the results showed that the improved restorer lines were resistant to rice blast and the recipient parents were all improved,but in the panicle blast resistance is weak.Formulating the compositions results show blast resistance rice blast resistance gene Pi-d1 and Pi-kh the expression thorough in restorer resistant hybrid breeding.In addition,they also showed higher levels of resistance in different CMS lines tested,indicating that resistance genes have a significant effect on rice blast resistance in rice combinations.3.In the agronomic traits,the improved restorer lines were improved in comparison with the original recipient parents.In the analysis of heterosis,DR1 has the most obvious advantages in combination,with an average of 13.8% the advantages compared to the male parentand 1.0% for advantages compared to compare.DR4-1 has a low setting rateand has a seed setting rate of less than 70% with three male sterile lines.The combination of TR2 and TR4 has a long-term problem in the growth period and is not suitable for the cultivation of middle-late rice.Although DR3 has a low seed-setting rate,a better combination of yield and agronomic traits is obtained in the use of matching.4.Indica and japonica materials used in the experiments,the InDel marker distance between parents is in the phenotypic value and superiority,negative correlation with plant height,panicle length and 1000-grain weight,positive correlation with total grain number,grain number,seed setting rate,effective panicles and yield.Among the parental parents,the InDel marker distance between parents was positively correlated with plant height,panicle length,total grain number,grain number and 1000-grain weight,and negatively correlated with seed setting rate,effective panicles and yield.