Genetic Diversity And Heterosis Prediction And Strong Advantage Combination Breedings Of Tomato

Tomato（Solanum lycopersicum）,which originated in the highlands of Peru,Ecuador and Bolivia in South America.As one of the most common vegetable in the world,tomato demand is increasing year by year,and the tomato industry is developing rapidly.The utilization of tomato heterosis can bring obvious economic,social benefits,and has become an important way to improve tomato quality,enhance tomato resistance and improve tomato yield.Therefore,heterosis prediction of tomato is the current hot topics in the study of tomato breeding this research adopts morphological markers and molecular markers of InDel for 115 tomato germplasm genetic diversity analysis,according to the parents and relatives or genetic distance to predict the strength of the F₁.Specific results are as follows:（1）Morphological markers were used to analyze 18 agronomic traits related to yield,prematurity and quality of 115 tomato materials.A total of 51 materials with positive comprehensive score of principal components were screened out,of which 14 were excellent materials with a score of 0.9 or above.According to cluster analysis,when the distance between Europe and Europe is12.5,115 materials are divided into 3 subgroups and 7 valuable parents are selected.The phenotypic variation level of fruit quality among different tomato materials was directly revealed,which provided theoretical support for the selection of excellent tomato germplasm resources,breeding new varieties and rational processing and utilization in the future.The DNA of parental materials was analyzed for genetic diversity using the InDel molecular marker.When the genetic distance was0.39,materials could be divided into 6 groups.Ten parents with research value were selected.It provides some theoretical guidance for tomato molecular breeding.（2）The strength and weakness of F₁ heterosis were predicted according to the relationship between selected parents or genetic distance.The former predicted that ZW07,ZW10 and ZW08had high heterosis,and predicted that ZW09,ZW03 and ZW21 did not have obvious heterosis.The latter can predict that ZW22,ZW31,ZW36,ZW42,ZW47,ZW48,ZW50,ZW51,ZW52,ZW63 and ZW66 have higher advantages.The heterosis of ZW27,ZW34 and ZW39 was not obvious.（3）By comparing the effect of the two methods,we found that the morphological marker to predict heterosis of fruit weight,but it doesn’t fit according to the genetic relationship and the highest heterosis combination forecasting system.The strong dominant combination may also occur when the genetic distance of InDel molecular marker is small.The optimal combination of single fruit weight and cell yield can be predicted by materials near the genetic extreme value.The InDel molecular marker heterosis is more accurate and accurate than the morphological marker from the advantages and disadvantages of screening good parents,prediction combination and the Heterosis strength of the matching group.It also saves time and labor,avoids field work and reduces the workload.（4）According to the analysis of four heterosis indexes,the former selected the materials with the strongest heterosis,including ZW01,ZW02,ZW11,ZW12,ZW14,ZW16,ZW17 and ZW18.The latter materials with the strongest heterosis include ZW22,ZW23,ZW24,ZW27,ZW29,ZW30,ZW42,ZW45,ZW48 and ZW55,thus creating a number of excellent tomato combinations with good theoretical and practical significance.