Identification of Broad and Narrow Genetic Base Testers for Waxy Corn Improvement

Abstract

Identification of waxy corn testers has not been investigated in diallel cross. The objective of this study was to identify narrow-base testers and broad-base testers in waxy corn breeding programs using diallel cross. A total of 90 crosses were generated from 10 parental lines differing in genetic backgrounds. They were 4 inbred lines, 2 single-cross hybrids and 4 open-pollinated varieties. Ninety crosses and their 10 parents were tested in a randomized complete block design with 3 replications in the rainy season (May-August) 2008. Fresh weigh of marketable ears, specific combining ability and variances of tested progenies were used as selection criteria. The inbred tester “101” as female parent was able to identify 3 of 4 male parents with high general combining ability (GCA) for marketable ear fresh weight, and it was also able to identify the best 2 hybrids from these high GCA lines, whereas the broad-base tester “SLE” was able to identify the best 2 parents and the best 2 hybrids from these high GCA lines. Similarly, the inbred tester “204” as male parent was able to identify the best 3 parents and the best 2 hybrids, whereas the broad-base tester “919W” was able to identify the best 3 parents and the best 1 hybrid from these high GCA lines. The inbred tester “101” also gave the progenies with the highest variances when used as male and female parent. Diallell cross could be used as an alternative method in identifying testers in breeding programs.