Inheritance of fruit cracking resistance of melon (Cucumis melo L.) fitting E-0 genetic model using major gene plus polygene inheritance analysis

Abstract Melon ( Cucumis melo L.), an important cash crop, is cultivated worldwide. Fruit cracking frequently occurs during ripening, resulting in economic loss. Thus, increasing fruit cracking resistance is crucial in melon breeding. However, until recently, few reports have described standard evaluation and identification methods for fruit cracking resistance or the genetic analysis of this trait, hindering the development of crack-resistant melons. In the present study, a mixed major gene plus polygene inheritance model was used to analyse fruit cracking resistance in six generations (P 1 , P 2 , F 1 , B 1 , B 2 and F 2 ) of melon, using the cracking-susceptible variety ‘MOIN-10’ and the cracking-resistant variety ‘RE-33’ as parents. The results showed that the genetic model E-0, incorporating two additive–dominance–epitasis major genes plus an additive–dominance–epitasis polygene, is the best-fitting genetic model for fruit cracking resistance. The heritabilities of the major genes in the B 1 , B 2 and F 2 populations for fruit cracking resistance were 46.24%, 59.19% and 57.98%, respectively, and the heritabilities of polygenes for this trait were 21.26%, 2.02% and 9.74%, respectively. Genetic variances in B 1 , B 2 and F 2 accounted for 67.51%, 61.19% and 67.73% of phenotypic variance, respectively, showing that fruit cracking resistance was controlled through genetic factors and environmental influence. Thus, in melon breeding, selection for cracking resistance in early generation melon is desirable.