QTL Mapping Analysis Of Rice Texture Characteristics

With the development of people’s better living,the requirements for rice quality,especially good tasting quality,have been continuously improved.Rice texture is considered to be one of the most important indicators of rice tasting quality.In this study,the recombinant inbred line（RIL）population constructed by Asominori and IR24,the substitution population（CSSL）of the IR24 chromosome segment constructed with Asominori as the genetic background,and the secondary F₂ population constructed by crossing the corresponding replacement line with Asominori were used as experimental materials,To investigate the texture characteristics of rice（Hardness,Adhesion Force,Adhesiveness,Cohesiveness,Springiness,Gumminess and Chewiness）,and use molecular markers to map the quantitative trait loci（QTL）which provide a theoretical basis for high-quality rice breeding.The main results are as follows:1.QTL detected in the texture of fresh riceIn 2017 and 2018,a total of 41 QTLs were located using the RIL population,distributed on 10 chromosomes other than 5,6,with LOD values between 2.00-4.58,and a contribution rate between 4.40%-23.74%.Among them,4 QTLs were detected in two years,and the remaining QTLs were only detected in one year.The QTL detected at the same time:Hardness:q HN-7,located in the RM505-RM118 segment of chromosome 7,with LOD values of 2.88 and 2.28,and contribution rates of 6.65%and 5.81%,respectively.The additive effects are derived from IR24;Cohesiveness:q CON-2,located in the RM5390-RM1313 segment of chromosome 2,with LOD values of 2.35 and 2.14,and contribution rates of 5.10%and 4.88%,respectively.The additive effects are derived from Asominori;Gumminess:q GMN-3,Located in the RM523-5474 segment of chromosome 3,with LOD values of 2.15 and 2.87,and contribution rates of 5.11%and 6.68%,respectively.The additive effects are derived from IR24.q GMN-7,located in the RM505-RM118 segment of chromosome 7,with LOD values of 4.58 and 2.11,and contribution rates of 10.00%and5.28%,respectively.The additive effects are derived from IR24.2.QTL detected in the texture of regenerated riceIn 2017 and 2018,a total of 32 QTLs were located using the RIL population,distributed on 10 chromosomes other than 7,12,with a LOD value between 2.00-4.18,and a contribution rate between 4.77%and 12.55%,Only 1 QTL is detected in 2 years,and the remaining QTLs are detected in only one year.The QTL detected at the same time:Cohesiveness:q CON-3,located in the RM523-RM5474 segment of chromosome 3,with LOD values of 4.18 and 2.83,and contribution rates of 12.55%and 7.80%,respectively.The additive effects are derived from IR24.3.Using CSSL to verify QTL of rice textureFresh rice:The Hardness of the segment substitution line CSSL40 corresponding to the chromosome segment where q HN-7 located is significantly increased compared to Asominori;the Gumminess of the segment substitution line CSSL14 and CSSL15corresponding to the chromosome segment where q GMN-3 located is significantly increased compared with Asominori,the Gumminess of the segment substitution line CSSL40corresponding to the chromosome segment where q GMN-7 located is significantly increased compared with Asominori.4.Use the secondary F₂ population to detect the q HN-7 LocusUsing the corresponding replacement system CSSL40 to backcross and self-cross with Asominori,construct a secondary F₂ population,Analyze the quantitative trait Loci that control the hardness of fresh rice.A total of 241 families were tested,and 7 polymorphic SSR markers were screened.2 QTLs was detected in the RM21975-RM21985 and RM21985-RM8261 intervals.The LOD values and contribution rates were 3.37,4.55 and6.46%,9.78%.Since these two QTLs are adjacent,we need to further expand the group encryption map to verify whether it is the same site.