Stability of maize hybrids with different proportion of sterile plants in the field

Three maize hybrids of different maturity groups – Kn 442, Kn 509 and Kn M 625 – were tested for a 6 years period (2014 – 2020), in three variants for each hybrid: 100% fertile plants; 50% fertile / 50% sterile; and 100% sterile plants. Sterility was obtained by hand detasseling before the ear flowering. Three-factor Analysis of Variance (ANOVA) for grain yield indicated significant variances for trial years, hybrids, and their interaction. The variants of the hybrids (% detasseling) had no significant variances, nor did their interaction with years. The triple interaction – (years) x (hybrids) x (% sterility) is also insignificant. Stability parameters according to Eberhart and Russell (1966) indicate the highest yielding hybrid in the trial, Kn 442, as responsive to favorable conditions. The fertile variants of Kn 509 and Kn M 625 are of stable type with significant low values ​​of the first stability parameter (bi<1.0). In all three hybrids, there is a consistent tendency for their sterile variants to have higher bi values ​​than their fertile variant, i.e. to lean towards a responsive type. The observed "drift" of the parameter bi towards higher values ​​in the 100% sterile variants means that under more favorable growing conditions, or intensive technology, from a mixed crop of hybrids, a higher yield can be expected, thanks to the sterile plants, which is in support of the so-called "System Plus".