RESPONSES OF TRADITIONAL AND IMPROVED UPL AND RICE CULTIVARS TO DIFFERENT MOISTURE REGIMES

A greenhouse experiment was carried out in Areia, Paraiba, PB, Brazil, to evaluate responses of two traditional (Caqui and Vermelho) and two improved (IAC 165 and Guarani) upland rice (Oriza sativa L.) cultivar s to four soil moisture regimes (60-70%, 70-80%, 80-90% and 90-100% of the field capacity). The experimental design was completely randomize d in a 4 x 4 factorial arrangement with four replications. The growth and yield parameters evaluated were: leaf area, 1.000 grains weight, p anicle length, panicle number, spikelet/panicle number, grain yield, r oot dry weight, shoot dry weight, total dry matter and harvest index. All parameters studied were significantly affected by moisture regimes except 1.000 grains weight and harvest index. The improved cultivar I AC 165 was the one that less decreased the grain yield and the total d ry matter, but the traditional 'Vermelho' was the one that showed the largest genetic potential under moisture regime more unfavorable.