Genetic Study On Fruit Traits & QTL Mapping For Fruit Shape In Eggplant (Solanum Melongena L.)

Eggplant is an important fruit vegetable crop,for its abundant nutrition and delicious flavors, is widely enjoyed by consumers. With high yields and remarkable economic benefits, cultivated area and output of eggplant increased. In 2009,The world's eggplant harvest area is 1.97492 million hectares and output up to 35.326379 million tons. The growth rate of past five years reached 17%, and china's harvest area is 1.05 million hectares,19.026154 million tons, share 50% of world. (FAO 2009).People of different areas have different spending habits for eggplant varieties,while fruit shape and fruit calyx color are important commercial qualities and a basis for eggplant breeding.In the present study,we chose four selfed eggplant lines as materials,which vary in fruit shape and fruit calyx color.Human measurement and computer photograph analysment were combined to get fruit traits' value.A joint analysis of P₁,P₂,F₁,B₁,B₂ and F₂ generations were used to study inheritance of the traits of fruit.In order to further understand the inheritance rule of eggplant breeding and MAS,we constructed eggplant linkage group between cultivated lines.The results showed below:1.Fruit shape:F₂ segregation population's fruit shape index in two hybrid crosses and fruit shape triangle index in hybrid crossâ… showed single peak skewed distribution,it proved that the fruit shape is quantitative trait and controlled by main genes.The inheritance of eggplant fruit shape is controlled by one additive major gene + additive-dominant polygene model(D-2 Modle) .Major gene heritability rate is highest in F₂ and polygene heritability rate is highest in B₂.In general eggplant fruit shape character inherance is controled by polygenes, the high fruit shape selection efficiency is in F₂.2.Fruit calyx color:The results showed that calyx color grade value of F₂ is single peak and partial distribution, it is proved that the fruit calyx color is quantitative trait controlled by multiple genes. The inheritance of eggplant fruit calyx color is controlled by two additive-dominant-epistatic major gene + additive-dominant-epistatic polygene model(E-0 Modle) . It with high main gene heritability is 96.82% which can be used in breeding.3.An AFLP and SSR genetic linkage map was constructed in eggplant (Solanum melongena L.) with an intraspecific F₂ population derived from a cross between an inbred line 106 and 113. The generated map contained 85 AFLP markers and 22 SSR markers consisted of 15 linkage groups with a total coverage of 1007.9 cM and an average interval of 9.3cM. The markers distributed randomly across the groups and could be done preliminary QTL mapping.Two QTLs for fruit shape, four for fruit length and two for fruit width were detected and explained up to 45% of phenotypic variances.