Study On Pyramiding Three Disease And Insect Resistance Genes Of Rice Elite Material

The production will decrease greatly once the brown planthopper,bacterial blight or blast occur,which are major pest and diseases in rice.Studies have shown that breeding and planting resistant varieties of rice is the most economical and environmentally friendly method to control pests and diseases.It also has been confirmed that the combination of marker-assisted selection with traditional breeding technology could enhance breeding efficiency and shorten breeding period.The resistance against diseases and insect pests of rice could be improved significantly when multiple resistance genes were pyramided to one material.In this study,four genetic disease and insect resistance genes were pyramided in rice by hybridization,backcross,reciprocal hybridization,and molecular marker assisted selection(MAS),the four main genes were the blast resistance gene Pi1,the bacterial blight resistance gene Xa7 and the brown planthopper resistance gene Bph6,Bph9.Ten kinds of materials with different combinations of genes were obtained,and the resistance and agronomic traits were analyzed,and the main results were as follows:(1)The 10 types of gene combinations were: one kind of four gene lines(Pi1/Xa7/Bph6/Bph9),four kinds of three gene lines(Pi1/Xa7/Bph6,Pi1/Xa7/ Bph9,Pi1/ Bph6/Bph9,Xa7/Bph6/Bph9)and five kinds of two gene lines(Pi1/ Bph6、Pi1/ Bph9、Xa7/Bph6、Xa7/ Bph9、Bph6/Bph9).The identification results of resistance to diseases and insect pests indicated that the materials with resistance gene Pi1 showed resistance or moderate resistance to rice blast,and the materials containing resistance gene Xa7 showed high resistance or resistance to bacterial blight,and the materials containing Bph6 only or Bph6 and Bph9 showed resistance to brown planthopper,while it showed moderate resistance when only Bph9 was contained.Pyramiding a number of resistance genes into the same material did not affect the effect of each gene,and they still showed strong resistance,however,there was no obvious additive effect or interaction between Bph6 and Bph9.(2)The date of heading,plant height,grain size,grain number per panicle,seed setting rate,1000 grain weight and plant weight of 10 kinds of materials were investigated,the result showed that the heading date of the 10 materials was higher than that of the receptor parent,and reached significant or extremely significant level;The ratio of grain length to width decreased in different degree;Seed setting rate was significantly or significantly reduced,thousand grain weight was significantly increased,and there was no significant difference in average effective panicle number and yield per plant.(3)The four gene polymerization materials which contained the blast resistance gene Pi1,the bacterial blight resistance gene Xa7 and the brown planthopper resistance gene Bph6,Bph9,showed resistance to rice blast and brown planthopper,and showed high resistance to bacterial blight.The plant height was equivalent to that of the receptor parent.The ratio of grain length to width,grain number per spike and seed setting rate were significantly decreased,grain weight was significantly increased,and there was no significant difference in the number of effective panicles per plant and yield per plant.Its comprehensive character was excellent.Three genes pyramiding materials,containing rice blast resistance gene Pi1,bacterial blight resistance gene Xa7 and brown planthopper resistance gene Bph6,showed resistance to rice blast,bacterial blight and brown planthopper.The plant height at heading stage was significantly lower than that of the receptor parent,and the grain size was close.The grain size was close to that of the parents,the seed setting rate was significantly reduced,and the 1000 grain weight was significantly increased,and there was no significant difference in yield per plant and average grain number per spike.The comprehensive characters were good.Three genes pyramiding materials,containing rice blast resistance gene Pi1,bacterial blight resistance gene Xa7 and brown planthopper resistance gene Bph9,showed resistance to rice blast and bacterial blight,moderate resistance to the brown planthopper.The plant height at heading stage was significantly lower than that of the receptor parent,and the grain length width ratio decreased significantly.The average number of grains per spike was not significantly different,the seed setting rate was reduced significantly,meanwhile the 1000 grain weight was increased significantly,the yield per plant and the effective panicle number were not significant.The comprehensive characters were good.