Interactive Influence of Location and Variety on Physiological Quality of Cowpea Seeds (Vigna unguiculata (L) Walp.)

The production environment plays a significant role in the production of high-quality seeds. Therefore, the knowledge of the relative contributions of the different factors that impact seed quality will be important for the management of seed production. The objective of this study was to assess the relative contribution of location and variety to the physiological quality of the cowpea seeds. Seeds of two varieties of cowpea, IT97K-918-118 and 977K-1499-35 were produced at three locations: Ikenne, Ilora, and Ballah. Hundred seed weight, seed moisture content, standard germination, accelerated ageing germination and electrical conductivity tests were carried out on the seeds. The results indicated that the location effect was highly significant (P<0.05) for hundred seed weight, germination percentage, germination rate index, accelerated ageing germination percentage and accelerated ageing germination rate index, while the varietal effect was highly significant for only hundred seed weight. However, location alone contributed more than 50% to the observed variability in hundred seed weight, germination percentage, germination rate index and accelerated ageing germination percentage. Seeds from Ballah had the highest viability (germination percentage = 84.67%) but also the lowest vigour (accelerated ageing germination = 11%; electrical conductivity = 64.10µscm-1g-1). Thus, the modulating effect of the environment on the quality of cowpea seeds is not the same for the different components of quality and the choice of location for the production of cowpea seeds should be given a higher priority than a choice of variety per se.