Breeding New Rice Lines With Blast Resistance As Well As High Yield And Quality Using MAS Strategy

In recent years,a large number of improved rice blast resistant materials have been obtained by molecular marker-assisted selection(MAS)breeding using the broad-spectrum rice blast resistance gene Pi9 or Pigm.We selected seven series from these improved materials: R599-Pi9,R389-Pi9,R747-Pi9,R640-Pi9,R640-Pigm,R527-Pi9 and R527-Pigm.Each series was composed of several high-generation materials,a total of 21 high-generation materials.By comparing the differences of field blast resistance performance,main agronomic traits,yield traits and quality traits between the improved material and the corresponding receptor parents,to breed excellent rice lines with blast resistance,high quality and high yield.The main results were as follows:1.In the spring of 2018,seven improved series were planted in the blast nursery of Daweishan in Liuyang Hunan and comparison on seedling blast resistance of 21 tested improved materials.The seedling blast resistance result were as follows: R747-Pi9-415 and R640-Pi9-339 showed moderate-level resistance,R389-Pi9-002 and R527-Pi9-299-2 showed high-level resistance,and the rest materials were resistant.There are no resistance phenotype segregation in each population of all improved materials,but all receptor parents were susceptible in this assay,implying that the rice blast resistance improvement was effective by MAS strategy in this study.2.DNA of all tested materials were extracted for genotypic identification.The results showed that all 21 improved materials were testified harboringthe Pi9 or Pigm homozygous allele.It was also found that the blast resistance of the improved material was much stronger than that of the receptor parents,which proved that the introgressed Pi9 or Pigm gene was normally expressed in different genetic backgrounds.3.Through the analysis of main agronomic traits,most of the improved materials showed higher effective filled grains per panicle and seed setting rate than the receptors.All materials with significant differences in 1000-grain weight are negatively altered.The theoretical yields of the four materials R599-Pi9-235,R747-Pi9-402,R747-Pi9-415 and R640-Pigm-345 were increased extremely significantly,while R599-Pi9-232,R599-Pi9-234,R640-Pi9-360,R640-Pigm-346 were significantly increased comparing to their receptor parents.4.In the comparison of appearance quality,most improved materials showed no difference with that of the receptors.In the comparison of milling quality,only R747-Pi9-416,R747-Pi9-415,R640-Pigm-348 and R527-Pigm-302 showed better than that of the receptors,while other improved materials is not different from that of the receptors.In comparison of cooking quality,R747-Pi9-402,R747-Pi9-415,R747-Pi9-416 and R640-Pi9-338 showed better than that of the receptors.According to above results,four improved rice lines,R599-Pi9-235,R747-Pi9-402,R747-Pi9-415,and R640-Pi9-338,showed much better in complicated traits of blast resistance,rice quality and yield than that of their receptor parents,could be used in application.The yield of R599-Pi9-232,R599-Pi9-234,R640-Pi9-360,R640-Pigm-345,R640-Pigm-346 showed increased,but rice quality was similar to the receptors and could be used for candidate rice lines.The rest tested materials showed no particular traits,and should be further improved or elimination.