Combining ability and genetic divergence in the selection of testers regarding grain yield and forage potencial in maize topcrosses

Genetic divergence analysis among testers and progenies associated with the combining ability and genetic parameters estmates can help in the selection of testers for the evaluation of grain yield and forage related traits in topcrosses, since testers suitable to both purposes are rare.The objective of this work was to select testers suitable for the evaluation of grain yield and forage traits is topcrosses with S3 progenies of maize based on the association between genetic divergence, general combining ability and genetic variance. The experiments were carried out in the 2015/16 and 2016/17crop seasons in Guarapuava-PR. We evaluated 150 topcrosses among 30 S-3 progenies and testers five testers (single hybrids AG8025 and P30B39, the elite inbred lines 60.H23.1 and 70.H26.1, and a mixture of inbred lines MLP102), The evaluated traits were plant height, ear height, grain yield, dry mass yield, neutral detergent fiber and acid detergent fiber and forage in situ digestibility. The testers 60.H23.1 and 70.H26.1 are the most recommended for discriminate the progenies regarding grain yield and forage traits. There was not linear correlation between genetic divergence, general combining ability and genetic variance.