Classical and AMMI methods to select progenies, testers and topcrosses hybrids in corn¹

ABSTRACT

The objectives were to estimate the potential of S₂ corn progenies for forage-related traits, and use of AMMI analysis to evaluate topcrosses compared to the classic analyzes. Progenies were crosses with four different testers: LG 6030, 2B688, 9.H3.33 and 53F.P37. Topcross hybrids were evaluated in four 9 x 9 simple square lattice design, during the 2017/18 season at Maringa, Parana State. Grain yield, forage fresh matter yield, and forage dry matter yield were measured. Classical approach was composed by variance components, general and specific combining ability, whereas AMMI analysis was performed for progenies x testers interaction, considering additive main effects and multiplicative effects. Considering the classical approach, testers LG 6030 and 2B688 better expressed the genetic variability between progenies for grain yield. AMMI analysis allowed the partitioning of the sum of squares in additive main effects and multiplicative effects, being a complementary result for the classical approach. Progeny 14 was selected due to higher general combining ability for grain yield, forage fresh matter and forage dry matter yield. Topcrosses 14x9.H3.33 and 14x2B688 were selected due to their higher specific combining ability, additive and multiplicative effects. The AMMI analysis was effective and helped in the interpretation of the results.

Keywords
Zea mays L.; testcrosses; diallel analysis; tester x progeny interaction