Establishment Of Heterotic Groups And Prediction Of Heterosis In Pepper(Capsicum Annuum L.)

Pepper（Capsicum annuum L.）is an economic vegetable crop with obvious heterosis in the world.The basic of heterosis is still not clear.Therefore,it is of great essential to carry out the prediction of heterosis and the division of heterotic groups of peppers for strengthening the utilization of heterosis and improving the breeding efficiency.In this study,31 pepper materials were selected from 312 pepper（Capsicum annuum L.）germplasm resources based on the re-sequenced data,with their geographical sources,genetic relationships and ecological types.413 cross combinations were used by complete diallel cross.Four yield related traits（yield per mu,number of fruit,single fruit weight,plant yield）and 12 agronomic characters of all combinations were investigated.The heterosis and combining ability of materials inter-groups and intra-groups were analyzed.The main research contents and results are as follows:1.Based on the re-sequenced data analysis,312 accessions of pepper（C.annuum L.）germplasm resources were devided to 8 genetic groups.Gourp I,II,III,IV,V,VI,VII,VIII has 27,76,19,20,33,37,50,41 accessions respectively.9 accesions are not included.2.The relationship between F₁ yield heterosis of different materials and genetic distance of parents was analyzed by using 12 backbone inbred lines from 31 parents.It was found that:75%of them were consistent with the law that the farther the genetic distance was,the stronger the over standard heterosis was,58.3%of them were consistent with the law that the genetic distance was far,and the over medium heterosis was strong;413 combinations of 31 materials were also studied and found that all combinations were on the whole in line with this law.The results showed that within a certain range of genetic distance,the greater the genetic distance between parents,the stronger the heterosis of yield.3.By using 31 parental lines,combining ability be found can predict yield heterosis,93.3%of cross combinations followed the rule of higher heterosis of GCA parents or single parent,inter-groups had higher heterosis than intra-groups;I group,VII group and V group had strong heterosis,the best yield group crossing mode I×VII group,I×IV group,I×V group,II×IV group,V×VI group.4.By the analysis of heterosis and combining abilityof 12 agronomic traits of pepper,significant positive correlation was found between fruit weight,leaf length,leaf width,vertical diameter,horizontal diameter,flesh thickness,fruit stalk length with plant yield and yield;In the traits of leaf width,he horizontal diameters,the vertical diameters,fruit handle length,V,VII,VIII groups showed significant positive GCA effect;V×V group,V×VII group and IV×IV group had high specific combining ability and good performance,which was beneficial to the construction of heterosis.It can provide reference for heterosis utilization mode and selection of high-quality combination.