Genetic evaluation of inbred plants based on BLUP of breeding value and general combining ability

Abstract

The testcross method is considered efficient for identifying inbred families with superior general combining ability. The objective of the present study was to assess the relative importance of the performance per se and in crossing in the selection of inbred progenies using bi-trait best linear unbiased prediction. We analysed data for expansion volume (EV) and grain yield from three tests of popcorn (Zea mays L. ssp. everta) S3 families and seven testcross trials, using the ASRemL software. Four selection strategies were assessed based on: breeding value (strategy 1), general combining ability effect (GCA) (strategy 2), additive value and GCA from strategies 1 and 2 (strategy 3), and breeding value and GCA predicted by bi-trait analyses considering EV and yield of the families and testcrosses as different traits (strategy 4). The bi-trait analyses of the same characteristic assessed in S3 families and topcrosses were generally more accurate and had greater heritabilites. The greatest predicted gains in EV were obtained using strategy 4, which was inferior to the other strategies for the yield predicted gains. Strategies 1 and 2 differed most for the families selected. Selection based on GCA maximised heterosis. All of the strategies resulted in comparable realised gains, especially the strategies 3 and 4 based on breeding value and GCA. Selection on S3 based on the additive value and GCA (strategies 3 and 4) resulted in inbred lines superior in number of favourable genes and in general combining ability.