Genetic progress obtained by upland rice breeding in twenty one years of research in the state of Minas Gerais, Brazil

This work aimed to estimate the genetic gain obtained by the upland rice (Oryza sativa L.) breeding program developed in Minas Gerais State, Brazil, in cooperation with Empresa de Pesquisa Agropecuaria de Minas Gerais (Epamig), Embrapa-Centro Nacional de Pesquisa de Arroz e Feijao (CNPAF), Universidade Federal de Lavras (UFLA) and Universidade Federal de Vicosa (UFV), from 1974/75 to 1994/95. Results of the comparative trials of upland rice cultivars and lines conducted over the above quoted period were utilized. Because of irregular rainfall distribution and the distinctive response of different cycles to climatic conditions, the option was to divide them into two groups, one encompassing the early genotypes and the other those of medium cycle. The achieved result showed that an average genetic gain of 1.26% and 3.37% for the early group and medium cycle, respectively, occurred. In addition, it was found that the early group statistically outyielded (P less than or equal to 0.01) as to grains the medium cycle group, denoting that in Minas Gerais the short cycle cultivars should be preferred.