Genetic Control on Resistance of Melon (Cucumis melo L.) to Yellow Virus Disease

Abstract

Resistance to yellow virus (YV) is an important breeding character in melon. However there is limited information regarding the genetic inheritance of the character. This study aimed at providing information on genetic control for resistance to YV in melon. The research consists of three field experiments, there were evaluation of resistance to YV and parent selection, evaluation of resistance in P1, P2, F1 and F2 population, and agronomic character evaluation. The research was conducted in July 2011 - September 2012. Twenty genotypes from three major melon groups were evaluated and one line from the dudaim group (MEV1) was high resistance to YV, other lines belong to cantaloupe and inodorous showed highly susceptible performance. Resistance screening of F1 from resistance x susceptible parent showed resistance among the F1. Resistance evaluation in F2 population showed disease severity score was not in normal distribution. It means that resistance to YV was controlled by major genes. Chi square test result gave 13:3 as a suitable ratio, which the resistance to YV was controlled by two gene pair with dominant and epistasis recessive action. Nineteen genotypes were grouped into four major groups by clustering analysis with 25 variable in 85% similarity level. Group I consist of seven genotypes, MEV2, MEV3, MEV4, MEV5, MEV6, MEV7 and MEV8 (susceptible parent from cantaloupe group). Group II consist of two genotypes, MEV18 and MEV19 that belong to susceptible parent from inodorous group. Group III consist of seven genotypes, MEV2X1, MEV3X1, MEV4X1, MEV5X1, MEV6X1, MEV7X1 and MEV8X1 as a resistance F1 (cantaloupe x dudaim). Group IV consist of three genotypes, MEV18X1, MEV19X1 as a F1 ( inodorous x dudaim) and MEV1 that belong to resistance parent from dudaim group. Path analysis showed that strong leaf blade dentation gave highest negative direct effect toward virus intensity, with -0.529 as a coefficient value. It mean that leaf blade character linked with resistance to YV. Selection to plant which weak leaf blade dentation will be more enable to obtain plant which resistance to YV.