Aline Cardoso de Souza
Abstract:
The study of genetic variability in populations is of great importance to the breeder, as it allows to evaluate the quality of populations for selection and use in breeding programs. The aim was to obtain information about the genetic variability of semiexotic populations in the second recurrent selection cycle and to evaluate them for their agronomic potential and the possibility of gains in a new selection cycle. Seven randomized block experiments were installed in Jataí-GO, with different sets of half-sib families obtained from three semiexotic populations (CRE-01, CRE-02 and CRE-03), evaluated in three replications of 4m plots (spacing 0.90m) with 20 plants. Genotypes were analyzed based on thirteen phenotypic characters. The average grain yield (PG) as percentage of commercial controls, P30K75 and SHS 4080, were 93.8%, 89.4% and 94.6%, respectively for the three populations, showing a good yield potential. For plant height (AP) and ear height (LA), the means were 221.4, 237.0, 241.5 cm and 116.7, 134.6 and 137.3 cm, respectively, indicating that of the population considered As a basis for the first recurrent selection cycle, there was a decrease of 10.3%, 4.3% and 7.6% and 17.4%, 8.7% and 12.3%, respectively. For PG (g plant-1) estimates of genetic parameters were as follows: additive genetic variance of 582.28, 406.70 and 238.11; heritability of 59.17%, 49.82% and 38.53%; variation index of 0.70, 0.58 and 0.46; gain with selection to 20% intensity of 8.16%, 6.86% and 3.88%; gain with selection for intensity of 5,81% of 10,81%, 10,47% and 5,32%, respectively for the populations CRE-01, CRE-02 and CRE-03. The semiexotic populations showed a pattern of genetic variability sufficient to continue the recurrent selection program.
