CULTIVARES DE MILHO NO ESPÍRITO SANTO: CARACTERES AGRONÔMICOS, ADAPTABILIDADE E ESTABILIDADE

Abstract

Corn (Zea mays L.) is one of the main cultivated cereals in the world. In some countries it is food base for population. It has great genetic variability, especially when it comes to of creole cultivars. These have been adapting to the conditions of each region where they are grown. can bring to modern cultivars, better performance, making them acquire resistance or tolerance to existing adversities. Corn is grown in all regions of Brazil with interference, positively or negatively, in their development and productivity. The objective of this work was to morphologically characterize maize cultivars from Espírito Santo Santo and identify adaptable and stable materials for the different growing regions of the state. For the morphology evaluations, an experiment was installed in DBC, with three repetitions, with three rows of 2 meters, spaced 1 meter apart and 0.20 meters between plants. The central row constituted the usable portion. Thirteen maize cultivars were evaluated, with nine creoles and four commercials, plus four commercial hybrids as a witness. You following characters were evaluated: female flowering, male flowering, period in anthesis, prolificacy, ear length, ear diameter, number of rows per ear, number of grains per row, cob diameter, thousand grain weight, productivity of grain per hectare, incidence of Spodoptera frugiperda, symptoms of helminthosporiosis, rust symptoms and white spot symptoms. The cultivars formed distinct groups for the evaluation of phenological characters (period in anthesis, female flowering and male), being the cultivar Milho branco SMJ (9) with the time in days for flowering female and male, 78 and 74 days, respectively. For prolificity, length and ear diameter and number of rows per ear, the cultivars did not differ statistically. For the number of grains per row, only the cultivar White corn SMJ (9) was different according to with the statistics, also presenting the lowest average (13 grains per row). Evaluating the diameter of the cob three distinct groups were formed, with the largest diameter being 28.30 mm and the smallest diameter of 18.5 mm. The highest grain yield was recorded for the cultivar Aliança (4) with an average of 5505.93 Kg/ha and the lowest average was 636.41 Kg/ha for the cultivar White corn SMJ (9). Regarding the incidence of the caterpillar and symptoms of the three diseases, incidence was recorded, with the exception of the white spot where minima were recorded symptoms only in the Fortaleza cultivar (3). For the evaluation of adaptability parameters and stability the 13 maize cultivars were evaluated in nine different environments distributed in the north, mountain and south regions of Espírito Santo. The experiments were installed in a randomized block design with three replications and plots composed of 4 rows of 2 meters. The useful plot consisted of the two central lines with the evaluation of five plants. Analyzes were performed using the methods of Annicchiarico, Eberhart & Russell, Lin & Binns, AMMI analysis and GGE biplot. There was interaction of cultivars with environments and methods used were concordant as to the results. The commercial cultivar Aliança presented the best results, with higher average productivity, which can be considered broad adaptability and stability for all environments. The creole cultivars Palhaográfica, Yellow Caiana, White corn and White corn SMJ and commercials Incaper 203, Incaper 201 and Fortaleza, are more suitable for favorable environments. The cultivars Agda Moreira, Alfredo Chaves, Catete, Domingos Martins and catetim are more suitable for unfavorable environments. And, the creole cultivars that presented the best performance in relation to productivity and stability indices were Alfredo Chaves, Catete and Catetim.