Abstract

On the Optimal Grain Yield of Cowpea Varieties in the three Senatorial Zones of Osun State, Nigeria

Ojo, Thompson O.1, *Ogunleye, Timothy, A.2, Olawuwo, Simeon3 and Adeleke, Mariam O.4

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Abstract This paper investigates the yield potentials of different varieties of cowpeas in each of the three senatorial zones of Osun State. Four common varieties of cowpea namely, IAR341, IT8D994, IAR1696 and LOCAL were considered in the experiment with one farmland selected from each zone as a block. Randomized complete block design (RCBD) with the assumption of random effect model was used in collecting the data sets on grain yields of cowpea varieties. Observations were taken from Iwo, Ila and Esa-Oke Farmlands representing Osun West, Osun Central and Osun East Senatorial Zones. Bartlett?s statistic was used to test for the validity of homogeneity of error variances for the data sets obtained from each zone. The test revealed that the assumption of equality of error variances was not violated. Shapiro-Wilk test was employed to check for validity of normality assumption on the data sets in each zone and, it was confirmed that departure from normality was not established. While the two assumptions were valid, ANOVA test was conducted on the data sets and the mean grain yields of cowpea varieties were found to be significantly different in the three zones. Duncan Multiple Range Test (DMRT) was employed to perform pair-wise comparisons among the four varieties of cowpea. Box Plots were drawn for cowpeas varieties in each zone with a view to recommending the best variety for planting. It was established that LOCAL produced highest grain yield while IAR1696 gave the least yield in Osun West Senatorial Zone. Furthermore the variety IAR1696 produced maximum grain yields in both Osun East and Central Senatorial Zones. Keywords: ANOVA, Bartlett?s statistic, Box Plots, DMRT, RCBD, Shapiro-Wilk test, Varieties of Cowpea.

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