Adaptabilidade, estabilidade e índice seletivo na recomendação de cultivares de feijão- caupi para produção de grãos verdes no estado do Ceará.

Abstract

Bean cowpea has great importance in food and in the generation of employment and income in the Northeast region of Brazil, especially for the state of Ceará, considered one of the largest producers of this legume. The objectives of this study were: (i) to infer about the adaptability and productive stability of cowpea genotypes, aiming to subsidize the recommendation of cultivars for the production of green grains in the state of Ceará and (ii) to elaborate a selective index that allows to assist in the recommendation of cultivars of cowpea for the production of green grains and to select the best genotypes based on it. Five trials of value of cultivation and use were conducted in five distinct locations in the state of Ceará: Acaraú, Pentecoste, Crato, Mauriti e Madalena. In these trials, 20 cowpea genotypes were evaluated, which included superior lines and cultivars. A randomized block design with four replications was used. The number of days to beginning of flowering, number of days to maturity, plant height, green pod length, number of bean grains from the green pod, green pod weight, weight of bean grains from the green pod, 100 fresh green bean grain weight, bean grain index, green pod yield , and fresh green bean grain yield. The analyzes of adaptability and stability of the yield of green grains, using the GGE biplot multivariate technique, made it possible to choose the MNC05-847B-123 and MNC00-595F-27 lines, as the best for the production of green grains in the state of Ceará. The relative importance of the characters was studied by means of the main components method, factor analysis and selection indices. Resulting in the following index: I3 = 0.079 NDBF – 0.083 HEI + 0.119 GPL + 0.034 PW – 0.176 100BSW + 0.340 PY. The application of this index made it possible to select the genotypes MNC05-847B-123, Azulão-MS, MNC00-595F-27, MNC99-541F-15, MNC05-835B-16 e MNC00-595F-2, as the most promising for the production of green grains.