Environmental adaptability and virus incidence in cowpea cultivars in Rio Grande do Norte, Brazil

Abstract

Among the causes of low yields of cowpea in the Rio Grande do Norte state, Brazil, are the low productive potential of materials planted, and viroses incidence. The searching for cultivars of high productive potential with phenotypical stability, wide environ-mental adaptability and resistance to viroses is the objetive of this study. Nine cowpea cultivars considered resistant to viroses, and the BR-13 Caicó cultivar were tested in five environments through 1989/1990. The statistic design used was that of randomized blocks with four replications, and the cowpea was planted in spacings of 1,0 m x 0,5 m with two plants per hole. The results were jointly analysed through linear regression, and the CNCx 658-18E cultivar was identified as ideal because of its stable behavior, wide adaptability and resistance to viroses. The CNCx 660-57E, 679-60E and BR-13 Caicó cultivars, besides susceptible to viroses, were unstable and with unpredictable environment behavior.