QTL Mapping Of Main Agronomic Traits In Pumpkin

In this study, a density genetic map was constructed in pumpkin(C. maxima Duch.) with F2 population, which including 186 lines derived from Rimu ×SQ026 a, using Genotyping by Sequencing(GBS) technique. And the significance QTL loci for starch content, seed length, seed width, seed color were detected using composite interval mapping approach. These results will be helpful for further gene fine mapping and molecular marker-assisted selection breeding in pumpkin. The main results obtained are as follows:1、Construction of genetic linkage map of pumpkinGenotyping by Sequencing(GBS) technique was used for SNP markers analysis between parents and among 186 F2 population, with average sequencing depth 0.5×. And the genetic map was constructed by Join Map4.0. The map contain 456 markers distributed in 20 chromosomes pumpkin genetic linkage groups, with a total length of 2356.94 c M, and an average linkage distance of 5.17 c M /per markers. The length of linkage groups are in the range of 41.67 ~ 229.71 c M. This is the first high-density genetic map in pumpkin(C. maxima Duch.).2、QTL Mapping analysis for starch content in pumpkinAnthrone colorimetry method was used to analyze starch content in pumpkin fruit. The linear regression equation for glucose content: y = 0.5724x-0.0009, correlation coefficient R2 = 0.9998. Anthrone colorimetry method are good in analysis stable, reproducible, and simple operation festures.QTL Ici Mapping V4.0 was used to identify the QTLs of starch content with the lingkage map described above. Two QTLs for starch content were mapped in linkage groups 3 and 11, named q Cms1 and q Cms2, and explained phenotypic variation 12.94% and 7.06%, respectively.3、QTL Mapping analysis for seed length and seed width in pumpkinThree QTL loci for seed length were detected in the 1st, 3rd and 10 th linkage group respectively named q Lms1, q Lms2, q Lms3, and explain 7.10%, 6.81%, 7.82% phenotypic variation. Three QTLs associated with seed width, located on 3rd, the 5th and 10 th linkage group, named q Wms1, q Wms2,q Wms3, and explained 5.78%, 9.58%, 8.23% phenotypic variation were detected here.4、QTL Mapping analysis for seed coat glossiness in pumpkinThree significant QTLs for seed coat glossiness, located on the second and ninth linkage group, wherein two QTL located on the ninth linkage group, named q Bms1, q Bms2 q Bms3, explained 11.60%, 90.91%, 74.73% phenotypic variation were detected.