ABSTRACT

One hundred and eight genotypes of cowpea were evaluated in 1999 for yield and associated characters at the research farm of Michael Okpara University of Agriculture, Umudike in the humid rainforest zone of South Eastern, Nigeria. The treatments were planted in single row plots in a randomized complete block design (RCBD) with four replicates. 1-lybridization was carried out on nine selected parents in 2000 and the F1, F2 and backcross generations obtained were used to study the inheritance pattern of yield and its associated characters and some qualitative traits such as leaf shape, pod shape, pod color, and seed coat color in 2001. Significant differences were observed among the genotypes for the attributes (P<0.00 1). A wide range of phenotypic and genotypic variability were observed for most of the attributes. Heritability was high for number of seeds/pod, dry matter yield/plant, Pod length, and plant height and moderate for seed yield. Similary, the genetic advance value followed the orler: dry matter/plant, plant height, pod length, and seed yield. Linear correlation coefficients showed that most of the attributes were significantly and positively associated with yield. Considerable positive and significant associations were also observed among the attributes themselves. Linear regression coefficients followed similar pattern as the linear correlation while multiple regression (stepwise) and partial correlation however showed that the observed yield were accounted for majorly by number of seeds/plant, and pods/plant. Positive and significant heteroses were obtained for seed yield and jts associated characters. Additive, epistatic and dominance gene effects were implicated in the inheritance of these traits while the qualitative traits were found to be monogenically controlled.