Genetic Analysis And QTL Mapping Of Peel Color In Pepper Fruit

To study the inheritance of fruit peel color traits of commodity maturity,this research object used three inbred lines of purple pepper line?245?,green pepper line?246?and white pepper line?247?as the parents,respectively made two hybrid combinations,which are 245×246 F₁and 245×247 F₁)andtheir respectively six genetic populations,which are P₁?P₂?F₁?B₁?B₂ and F₂).And this research adopted the combination of visual and chromatic meter to measure the L value,C value and class value of fruit skin color of commodity maturity on the generations of F₁,F₂,backcrosses B₁ and B₂ and their parents P₁ and P₂,and used the method of conjoint analysis on multiple generations to research the inheritance of peel color in pepper commodity maturity.The SSR molecular marker technique was used to get the gene mapping of the purple gene of pepper commodity maturity.And the changes of pigment content in four growth period of three pepper varieties were studied.The main research results are as follows:1.The inheritance of fruit peel color traits of commodity maturity accorded with the nucleus of genetic,and the major gene and polygene?D-2 model?inheritance of fruit skin color of commodity maturity in the purple-green combination accorded with the additive and hybrid additive-dominance pattern,the L value,C value and class value of major gene heritability in F₂ of the purple-green combination are 22.38%,91.39%and 82.26%respectively;and the major gene and polygene?E-0 model?inheritance of fruit skin color of commodity maturity in the purple-white combination accorded with the additive-dominance-epitasis pattern,the L value,C value and class value of major gene heritability in F₂ of the purple-white combination are 87.02%,94.34%and97.54%respectively.The major gene heritability in F₂ is all higher while the polygene heritability and environmental effect are all lower.So the fruit skin color of commodity maturity breeding should be selected in the early generation.2.The F₂ segregating populations of the combination?245×246?were used as the material.The blue and green gene pool was constructed by the method of separation group analysis?BSA?.A total of 144 primers from the pepper genome and 144primers of the tomato genome were screened.Three pairs of SSR primers were found between the two parents and the hybrid gene pool,which were CAMS-454,ES-148,hc-139733,respectively.Through constructing the linkage map,confirmed that three markers on the same linkage group.3.QTL mapping was performed on the color traits of 186 individuals of F₂population by CIM mapping method.A QTL locus was obtained between CAMS-454and ES-148 marker,LOD was 33.8,the additive effect was 1.5,the dominant effect was 0.5,the phenotypic contribution was 57%.The QTL locus has a high contribution rate,which is the main potential for controlling the purple gene of chili.According to the published genetic map galaxies,it is presumed that this locus is located on chromosome 2 of the pepper genome.4.The changes of pigment content in the process of fruit development of three pepper cultivars were studied.It was found that the changes of pigment of green pepper and white pepper were similar,that is,the contents of carotenoids and anthocyanins were increasing in the process of fruit development,the content of flavonoids decreased first and then increased.And only the total chlorophyll content changes are different,the green pepper showed a decreasing trend,the white pepper showed the trend of decreasing first and then rising.The results showed that the content of pigment in purple pepper was different,and the content of carotenoids increased gradually with the development of fruit,the contents of total chlorophyll and anthocyanin were increased first and then decreased,and the content of flavonoids was up-down-liters.