Genetic diversity analysis and Fusarium wilt resistance screening of bitter gourd germplasm resources

【Objective】To analyze genetic diversity of agronomic characters of bitter gourd germplasm in Jiangxi Province,so as to provide reference for the breeding and genetic improvement of bitter gourd varieties resistant to Fusarium wilt.【Method】From 2018 to 2020,identification of bitter gourd phenotypic traits and Fusarium wilt resistance was carried out in different places of Jiangxi province to analyze genetic diversity,conduct cluster and relationship analysis,so as to screen quality bitter gourd germplasm resources resisted to Fusarium wilt.【Result】 According to the results of comprehensive identification of phenotypic traits and diseases,the phenotypic traits of 55 bitter gourd germplasms had rich variations,with the genetic diversity index of 0.091-2.122 under different environmental conditions,and the diversity index of first female flower node was the highest,followed by that of fruit diameter and length. Germplasm resources were divided into four groups in the cluster analysis:group I,with great agronomic properties,early maturity,could be applied to improve varieties of early maturity and higher production;group II originated in Jiangxi province;group III,a good shape,was widely accepted by local customers,which could be used as parent material for improvement;and group Ⅳ were wild bitter gourd with small fruits which could be used for sight seeing and extracting functional substances. The correlation analysis showed that besides fruit gloss,significant correlation(P<0.05)or extremely significant correlation(P<0.01,the same below)existed among the 16 agronomic traits,among which weight per melon was significantly positively correlated to fruit diameter,fruit length,indicating that the yield could be improved by increasing the fruit diameter. The principal component analysis showed that the cumulative contribution rate of the five principal component factors was 77.544%. Four high resistance(HR),18 resistance(R),5 middle resistance(MR), 10 susceptibility(S)and 18 high sensitivity(HS)varieties were identified through Fusarium wilt resistance test.【Conclusion】The local ancient varieties of balsam pear in Jiangxi Province have rich genetic diversity and great breeding potential. Single melon weight, melon vertical and horizontal diameter, flesh thickness and melon tumor size can be improved as yield traits, and the node position of the first female flower and the number of female flowers can be screened as early maturing traits.