André Cavalet Chavaglia
Abstract:
The genetic variability present in maize crop allows it to be sown in several environments, therefore, selecting the most suitable plants for each producing region can improve crop yield. The population evaluated in the present work is a compound that was derived from commercial hybrids, which aims to estimate genetic variability, verify the productive potential and inbreeding depression for traits of agronomic importance and the tolerance level to cercosporiosis leaf disease. From the RV-02 population, 182 half-brother families (MI) were generated and distributed in 3 experiments and 80 S1 families. The design used was randomized blocks with 3 replications. Two controls were used, one moderately susceptible to cercosporiosis (SHS5050) and the second tolerant to cercosporiosis (AG1051). The genotypes were evaluated in 12 quantitative characters of agronomic interest: male (FM) and female (FF) flowering; plant height (AP) and ear height (AE); tassel length (CP) and tassel branch (RP); number of ears (NE); ear diameter (DE); spike length (EC); ear weight (PE); grain weight (PG) and evaluation of cercosporiosis (ADC). For the PG character, the MI families produced an average of 5.17 t ha-1, with a maximum yield of 9.79 t ha-1 and a minimum of 1.98 t ha-1, additive genetic variability of 312.74 g plant. -1, mean heritability of 59.14% and variation index of 0.70. Some families that did not differ statistically for grain production were classified tolerant to cercosporiosis. In the analysis of S1 families, PG obtained 3.27 t ha-1, heritability of 74.04% and inbreeding depression of 36.43%. The MI families and S1 families have genetic variability and productive potential to be exploited in breeding programs in addition to tolerance to the fungus Cercospora zeae-maydis.
