Cowpea Rust Disease Incidence and Severity on Growth and Yield of Selected Cowpea Genotypes under Different Cropping Systems in Western Kenya

Abstract

The effect of cropping systems on Cowpea rust caused by Uromyces phaseoli var vignae (Baarel) Arth,) was evaluated in five cowpea genotypes under two cropping systems; cowpea pure stand and cowpea maize intercrop at Busia and Kakamega in western Kenya in short rains 2018 and long rains 2019. The experiment was laid in a Randomized Complete Block Design (RCBD) in split plot arrangement where cowpea genotype was the main treatment and cropping system the sub treatment. Five cowpea genotypes; Katumani 80 (K80), KVU 27-1, Tumaini, Dakawa and one local check, “Lwanda black eye” (Local) were evaluated. Data was subjected to Mixed model ANOVA using SAS and means separated using LSD (p≤0.05). Cowpea genotypes in pure stand showed 35% lower disease incidence and 56% lower disease severity with higher leaf weights and grain yields than those in the maize intercrop in both Busia and Kakamega. Cowpea genotypes in intercrop were significantly taller than pure stand. Leaf Area Index (LAI) was higher in pure stand than intercrop. Dakawa and Tumaini had the highest LAI while K80 and local variety had the lowest in both Busia and Kakamega. Based on this result therefore it may be suggested that farmers adopt pure stand for more leaves and grain weight, however, for intercropping purposes they can use Dakawa and Tumaini cowpea genotypes as they have potential resistance to cowpea rust in both pure and intercrop.

Key words: Cropping system; Disease Incidence; Disease Severity; Cowpea rust; Intercrop