Detection Of Cold Tolerance QTLs Of Rice Early Seedling Stage And Booting Flowering Stage By Using Recombinant Inbred Lines

Chilling damage is one of the important factors affecting rice growth and seed setting.In order to resolve the hazard of low temperature on rice,breeding of cold-tolerant varieties and excavation of cold-tolerant genes have become particularly important.In this study,we developed a F₁₀ recombinant inbred lines?RIL?contain 253 individuality from Jileng 1 with cold tolerance and Miyang 23 with cold-sensitive as experimental material to identify the cold tolerance QTLs at early seeding stage and booting stage.The cold tolerance at the early seedling stage was treated at 5?in a light incubator,and the survival rate was used as a cold tolerance index.The low temperature treatment of the booting flowering stage was planted in the experimental field of Yunnan Academy of Agricultural Sciences?Kunming?for natural low temperature treatment,respectively.And normal conditions in Beijing as a control.We measured plant height?PH?,panicle length?PL?,panicle exsertion?PE?,number of panicles per plant?PN?,flag leave length?FLL?,flag leave width?FLW?,grain number per panicle?GPP?and percent seed-setting?PSS?of parents and populations in the maturation stage.Using ICIMapping4.0 to constructed genetic linkage map and mapping QTLs.A total of 79 QTLs were mapped at the early seedling stage and the flowering stage,and 3 QTLs were detected in the early seedling stage,and 76 QTLs were detected in the booting flowering stage.The main results are as follows:?1?A molecular genetic linkage map containing 118 SNP markers and 177 SSR markers was constructed,and average 24 polymorphic molecular markers per chromosome.The map covered the genome with a total length of 2240.31 cM and the average distance between markers was 7.59 cM.?2?The early seedling stage cold-resistance results of the recombinant inbred lines showed that the survival rate of the population after low temperature stress was lower than that of the survival rate of Jiliang 1;the early seedling stage cold-resistance results of the recombinant inbred lines showed that the phenotypic traits of the population under normal conditions in Beijing and natural low temperature conditions in Yunnan were normally distributed,except for the present seed setting.?3?Three QTLs related to cold tolerance were detected at early seedling stage,located on chromosomes 4,5 and 11,respectively.The source of allele were from Jiliang 1;and 76QTLs were detected at the booting flowering stage.Of which,11 QTLs with a contribution rate greater than 10%.And there are 12 regions that have multiple QTLs.Six QTLs could be repeatedly detected in more than two years under the normal conditions of Beijing.Four QTLs could be repeatedly detected in two years under natural low temperature conditions in Kunming Yunnan.Four QTLs could be repeatedly detected under the normal conditions of Beijing and natural low temperature conditions in Kunming Yunnan in these years.?4?There are three important cold-tolerant areas in all QTLs enrichment regions,which were RM486-RM315 on chromosome 1,RM255-S04107 on chromosome 4,and S06091-CMB0625.3 on chromosome 6.There have some important QTLs related to cold tolerance in these regions.The source of allele most of these QTLs were from the cold-tolerant variety Jileng 1.