Impact of Gibberellic Acid (GA₃) on Growth, Yield and Nodulation on Two Accessions of Cowpea (<i>Vigna unguiculata (L.)</i> Walp)

Abstract

Cowpea (Vigna unguiculata) is one of the most ancient crops known to man and is grown across various climatic zones, most commonly in the dry savanna regions of sub-Saharan Africa. The objective of this work was therefore to investigate the impact of Gibberelic acid on the growth and yield of cowpea. Field experiments was conducted during the 2019 rainy season at the Botanical Garden of Federal University of Lafia. The cowpea accessions were submerged into various concentrations of GA₃ (90mg/L, 120mg/L, and 150mg/L). The results showed varying response of the accessions in varying GA₃ concentrations. Both Accessions (TVU-1 and TVU-4) recorded no significant difference across all treatments in the number of flowers. In TVU-1 accession, the least concentration, 90mg/L recorded the highest number of flowers (0.22) at 12(WAP); while in TVU-4, the seeds exposed to the highest concentration recorded the highest number of flowers. Similar result was observed in the number of pods of both accessions (TVU-1 and TVU-4) were there was no significant difference (P≤0.5) recorded. There was increase in the number of root nodules with increased in the growth hormone concentrations as treatment 150mg/L showed the highest number of root nodules in both accessions; even though no significant difference was recorded. It is therefore recommended that different accessions at different concentrations of gibberelic acid be tired to see their responses.