GENETIC STUDIES AND EVALUATION OF SOME CUCUMBER GENOTYPES FOR CUCUMBER MOSAIC VIRUS (CMV) RESISTANCE AND SOME OTHER TRAITS

Abstract

Cucumber (Cucumis sativus L.) is one of the important vegetable crops in Egypt and the selection and planting of genotypes that are resistant to CMV is one of the most important components in an integrated disease control program. So, the objectives of this study were the identification of the resistance to CMV and estimating the genetic variance among ten cucumber inbred lines. This study was conducted during the period from 2017 to 2020. Selfing pollination to produce inbred lines and crossing to produce F1'S were carried out in the greenhouse at Kaha Vegetable Research Farm (K.V.R.F), Kalubia at spring season in 2017, and horticultural evaluation of the inbred lines and their hybrids was carried out in the greenhouse at Kaha Vegetable Research Farm and Ismailia Experimental Station at spring season in 2020, while evaluation of the inbred lines was carried out at Ismailia Experimental Station during (2017/2018) and evaluation of the selection inbred lines and their hybrids to CMV was carried out under greenhouse conditions at Ismailia Experimental Station during (2018-2019). In order to determine the genetic polymorphism and discriminate among these genotypes, RAPD analysis was conducted on the isolated DNA samples from each genotype. Viral diseases are important problem for production of cucumber in Egypt. The most important of these viruses in Egypt is Cucumber mosaic virus (CMV). The CMV was tested serologically using indirect ELISA. CMV has a wide host range belonging to 4 families. Finger prints of the studied genotypes were conducted using 3 RAPD primers. The produced hybrids were infected by CMV. P1 and P7 are the best inbred lines due to their high yielding ability, good fruit and vegetative traits. But only P1 is considered the most promising inbred line, due to its resistance to CMV. These lines could be used in CMV resistance breeding programs to be released as a new cultivar, which possesses both high yielding and resistance. The general performances of the F1 hybrids reflected the presence of three degrees of dominance effects complete, partial to over dominance and absence of dominance.