Improvement Of Single Segment Substitution Lines Of O.nivara And Identification Of Domesticated Genes

After long-term artificial selection,cultivated rice(O.sativa L.)has greatly reduced its genetic diversity,while wild rice retains abundant beneficial genes during the growth process in natural environment.Development of single-segment substitution lines(SSSLs)of the wild rices to introduce wild rice chromosome segments into cultivated rice genome,and exploiting potential trait genes in wild rice will not only help increase the production value of cultivated rice,but also help people explore and understand the evolutionary process of rice.In this study,a series of SSSLs of O.nivara were developed in the background of elite cultivar,HJX74,and several SSSLs carrying the genes related to domestication were selected,the traits wereseed shattering,spreading panicle,awn and prostrate growth habitat.The main results were as follows.(1)In this study,172 unique SSSLs were obtained from O.nivara as the donor and distributed on 12 chromosomes of rice.The total length of the substitutions was 2068.75 cM,which was equivalent to 1.36 times the size of the rice genome,and the total coverage length was 995.23 cM,covering 65.30% of the rice genome,of which 5 chromosomes covered more than 80%.(2)Two QTLs associated with rice domestication were identified by using chromosome segment substitution lines.The traits of shattering and spreading panicle were located on the chromosome 4 of rice and were identical to the previous reported gene SHA1 and SPR3.(3)Mapping the single-segment substitution lines which were identified for awn traits and prostrate growth traits,in which the awn trait is located within the 28.8 cM short arm of the chromosome 3 and the prostrate growth trait was located within the 64.6 cM of chromosome 11.We developed mapping population from cross between HJX74 and ZS6 as the donor which revealed that PROG2 is dominant gene.In summary,a series of SSSLs was developed by using O.nivara as a donor,and four genes related to domestication traits of rice were identified.This will be not only helpful to enrich the SSSL libraries in our laboratory and conserve wild beneficial genes in vivo,but also lay a solid foundation for the study of rice evolution.