QTL Mapping Of Carotenoids And Fruit-related Traits Based On Recombinant Inbred Lines Of Cucurbita Moschata

Pumpkin(Cucurbita moschata Duch.),belonging to Cucurbita of the Cucurbitaceae family is one of the important economic crops.It has wide variety,and high nutritional value.It has the reputation of "the king of vegetables" and is widely grown worldwide.Cucurbita moschata planting area and output rank first in the world.Pumpkin is a good nutritional and medicinal food,it’s rich carotenoids have many functions such as protecting eyesight,anti-oxidation and preventing various cancers.Fruit traits are important agronomic traits for horticulture crops.At present,it is an important goal of breeding to explore the molecular genetic mechanism of fruit related traits and to cultivate excellent pumpkin products with high nutritional value that consumers like.In this study,a high-generation inbred line of cucurbita moschata CMO-E and CMO-X were used as parents to establish a recombinant inbred line population with 122 progeny as the experimental material,to construct the high density genetic map of cucurbita moschata,genetic analysis of pumpkin major carotenoids(violaxanthin、lutein、α-carotenoids、β-carotenoids、total carotenoids)and related fruit traits(brix degree、fruit diameter、pulp thickness、 fruit peel level、pericarp stripe、 pericarp coloring、fruit moisture content)phenotypic data,and QTL mapping.The main results of this experiment are as follows:1.Using high performance liquid chromatography(HPLC)to determine the carotenoid content of the RIL population,genetic analysis and correlation analysis of the obtained phenotypic data,the results showed that: Due to differences in parent carotenoid composition,within recombinant inbred line population,violaxanthin content is 15.5μg/g-68.9μg/g,lutein content is 96.5μg/g-877μg/g,α-carotenoids content is 0-400μg/g,β-carotenoids content is 94.35μg/g-935.64μg/g,total carotenoids content is 323.8μg/g-2176.9μg/g,Significant difference.In addition,the carotene content traits are much higher than of their parents,and the content distribution chart showed that all types of carotene are continuous normal distribution,which is a typical quantitative trait;The content of 4 kinds of carotene is extremely significant with the content of total carotenoids.2.Field investigation and statistical analysis were carried out on 7 related traits of pumpkin RIL population,such brix degree、fruit diameter、pulp thickness、fruit peel level、pericarp stripe、pericarp coloring and fruit moisture content.The results showed that the pericarp stripe was a quality trait controlled by a single gene.The other 6 fruit related traits all showed continuous variation,with variation coefficient between 3.66% and 60.05%,and with normal distribution law,they were quantitative traits controlled by multiple genes.3.Using high-density genetic map combined with related phenotypic data,QTL analysis was performed on 5 carotenoids and 7 fruit-related traits,and 31 QTLs were detected on 12 linkage groups.These include 3 QTLs of violaxanthin、3 QTLs of lutein 、 2 QTLs of α-carotenoids 、 3 QTLs of β-carotenoids 、 3 QTLs of total carotenoids、3 QTLs of brix degree、2 QTLs of fruit diameter、2 QTLs of pulp thickness、4 QTLs of fruit peel level、1 QTL of pericarp stripe、2 QTLs of pericarp coloring、3 QTLs of fruit moisture content,single QTL phenotypic contribution rate is 2.96% ～ 46.9%.The results obtained in this study can lay the foundation for molecular marker-assisted breeding of important quality traits and agronomic trait-related genes in Cucurbita moschata,and have important significance for future pumpkin breeding work.