This study was conduced to identify cowpea genotypes early maturity with upright and determinate growth habit and with high grain yield potential. Twenty-two genotypes were evaluated. The research was carried out under irrigated conditions in the experimental field of Embrapa Meio-Norte in Teresina, PI, during the years of 2003 and 2004. A complete randomized block design with four replications was used. Characters relating to plant maturity, plant architecture and grain yield were evaluated. The treatment effects were significant to the majority of the characters. Broad sense heritability were high for the number of days to flowering (94.94%), pod maturity (93.79%), and lodging (91.93%). The most early maturing genotypes were: IT82D-889 (54.5 days), AU-94-MOB-816 (55.5 days), IT82D-60 (55.7 days), IT82G-9 (56.2 days), IT82E-49 (56.5 days) e MNC-00-544D-14-1-2-2 (56.7 days). The line UCR-95-701 was the highest of the trail (58.8 cm) and had the highest number of nods in the main branch (11.60 cm). The genotypes MNC-00-519D-2-1-1 (1.0), IT87D-611-3 (1.0) and IT91K-118-2 (1.0) had the lowest lodging index. The line TVx5058-09C had the best grain yield with 2,029.84 kg ha-1. Some characters were highly correlated like the numbers of the lateral branches and numbers of nods in the lateral branches (0.98), pod maturity and grain yield (0.92), harvesting time and grain yield (0.86), and the number of days to flowering and grain yield (0.78). The genotypes have complementary characteristics and the genetic recombination among them might make possible select early maturity lines, with erect plants and with high grain yield potential.
