EFFECTS OF SEASON ON AGRO-MORPHOLOGICAL TRAITS OF SOME MUTANT COWPEA LINES
A field experiment aimed at determination of influence of season on the yield potential of some cowpeas lines was carried out at the Teaching and Research Farm of Federal University of Agriculture, Abeokuta, Nigeria located on Latitude 7012' N and longitude 3020' E during the late rain season (August- November 2013) and early rain season (April- July, 2014). The experiment was laid out in a randomized complete block design with three replicates. Qualitative and quantitative data such as stem petiole pigmentation, leaf colour, flower form and colour, dry pod colour, seed coat texture, plant height, number of days to flower and first ripe pod, pod length , total number of pods/plant , total number of seeds/plant, 100-seeds weight were taken. Combined analysis of variance to determine line x season interaction, while SASTM 9.1, (2000) version statistical package was used to separate the means, Pearson correlation analysis was used to determine the inter-character relationships among the traits. Major characters causing variation within the population was calculated using Principal component analysis (PCA). Most of the cowpea lines were non-pigmented and papillinaeous, except Rosa-1 and 2 that showed rosaceous flower form. Cowpea lines such as Rosa-2, IF-Br-Y-2 and IB-Cyt.Y had yellow foliage, while the flower colour ranged from solid purple and white to white petal with purple wings. Line x season interaction revealed a high level of significance for most of the traits studied. Means of the cowpea lines traits were significantly different from one another. Pod length was highly correlated with number of seed per pod, pod per plant and 100 seed weight (r = 0.63, 0.45 and 0.66) respectively, while plant height had a negative and highly significant correlation with days to flowering (r = -0.58) and days to fruiting (r = -0.60).
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