DNA divergence as a criterion of a sweet pepper (Capsicum annuum L.) selection for heterosis

Abstract

The identification of perspective parental lines for the creation of highyield hybrids is the most laborconsuming stage of selection, because it needs exte nsive trials of combining ability. Based on evaluation of the genetic divergence of the parental lines, the prediction accuracy of F1 hybrids performance was inves� tigated. The value of the divergence was calculated using biometric and molecular methods, such as inter sim� ple sequence repeats (ISSR) and random amplified polymorphic DNA (RAPD). Based on estimates of diver� gence, 10 lines were chosen for cyclic cross (scheme I) and testcross (scheme II). In most crosses, the F1 hybrids were significantly superior to the parents in the main economically valuable traits. The level of het� erosis was higher among hybrids of scheme I. Analysis of the relationship between parental divergence and F1 performance showed that the hybrid productivity of scheme I was predetermined by ISSR divergence in 86%, and productivity was caused by RAPD divergence in 69%, whereas the F1 yield of scheme II was not related to the value of genetic distances. Since the values of DNA divergence were closely associated both with mid� parent level and F1 performance, we assumed that part of the polymorphic DNA fragments of the parental lines of scheme I is related to heterotic loci (HTL), which may be considered potential key markers for the heterotic selection of the sweet pepper.