performance and stability of maize topcross hybrids from partly inbred lines

Commercial hybrids are viable to generate base populations for obtaining new superior lines. Therefore, this study aimed to evaluate the performance and stability of maize topcross hybrids and select superior partly inbred lines. We evaluated 155 topcross hybrids of partly inbred lines crossed with an elite inbred line (tester) together with 14 commercial hybrids (2B688, AG7088, AS1575, DKB390, GNZ2005, GNZ8132, GNZ9501, GNZ9505, GNZ9548, GNZ9623, P30F35, P30F53, P30R50, and Penta) in Guarapuava-PR, Candói-PR, Guarda-Mor-MG, and Paracatu-MG (Brazil). The assessed variable was grain yield (GY), in kg ha-1, at 13% moisture, being the plant stand corrected by covariance method. A variance analysis was carried out, testing both stability and adaptability. There were significant differences for all sources of variation. By considering the GY means of the genotypes in each environment, Candói (10,985 kg ha-1) and Paracatu (10,917 kg ha-1) were in the first group, while Guarda-Mor (10,448 kg ha-1) was allocated in the intermediate group, and Guarapuava (10,159 kg ha-1) formed the group of lower GY means. None of the topcrosses stood out in any of the four environments, which may be related to the differences in climate and altitude between environments. Despite of this fact, lines 9, 13, 39, 40, 60, 93, 108, 179, 184, 189, 194, 211, 212, 213, 216, 217, 235, 243, 245, and 253 excelled as promising and should follow the process of inbreeding, in addition to the topcrosses 87, 144, 179, and 211, which also stood out for stability and adaptability in these environments.