Evaluation of seasonal rainfall changes on the growth performance of Vigna unguiculta (cowpeas) in Zimbabwe

Abstract

Climate change has been negatively affecting crop productivity in most parts of the world. This has affected the planting time of crops and resulted to reduced yield because of inappropriate planting dates. Marginalized crops like cowpea (Vigna unguiculata) are the most affected. Cowpea is an important but marginalized legume crop and a valuable component of cropping systems. The crop is adapted to harsh environments such as high temperatures and drought but yield can be compromised by low or too high temperatures and rainfall regimes. The changes to the onset of rainfall have necessitated a relooked to the recommended planting dates of many crops since they are now unsuitable to prevailing rainfall patterns. The objective of this field study was to investigate the effect of the planting time on growth performance of the two varieties Two commonly grown cowpea varieties (CBC 1 and IT18) were planted at three different times (early December, mid-December and early January). Growth and performance were characterized by measuring plant height, days to 50% flowering and final grain yield. Results showed that planting date had a statistical significant (p< 0.05) effect on cowpea height, days to 50% flowering and grain yield. The variety IT 18 performed better than CBC 1 at all three planting dates. Planting cowpeas in early December resulted in higher growth performance than in mid December and early January. Early planting (early December) is recommended for high yield and IT 18 may be grown late in the season.