Comparative Germination Responses of Cowpea and Maize Genotypes of Soil Moisture Content.
Germination, emergence and establishment phase are critical to the growth cycle of plant as it determines the density of the stand obtained. However, a number of factors including soil available moisture decrease seed germination and the rate of decline is found to vary with crop species. Pot experiment was therefore conducted to evaluate the germination responses of cowpea (Vigna unguiculata (L.) Walp.) and maize (Zea mays, L) genotypes to varying soil available moisture. Seeds of ten varieties each of cowpea and maize were germinated at three available soil moisture contents (25%, 50% and 100% field capacity). The moisture contents were determined gravimetrically. An experimental unit was a 10L pot filled with 10 Kg top soil, planted with 25 seeds and moistened to the required soil moisture content. Daily emergence was recorded from 5 days after planting (DAP) to 15 DAP. Data collected were used to estimate germination percentage (E%) and speed of germination as mean germination time (MGT). Both the speed of germination and final germination percentage were significantly decreased by inadequate soil moisture (25%) in both cowpea and maize with greater effect on cowpea which also showed greater genotypic variations in germinability at the sub-optimal moisture condition than maize. Speed of germination and germination percentage in cowpea were also reduced at water saturation condition (100%), while maize gave the best results at this moisture content. These results therefore suggest that both inadequate and too much soil moisture conditions are detrimental to seed germination in cowpea, while maize can tolerate the two conditions. Nevertheless, non-significant interactions of soil moisture and crop species suggest similar responses of genotypes of both species to soil available moisture, but with greater magnitudes in cowpea genotypes.
Keywords: Soil moisture content, crop species germination, cowpea and maize.
Agrosearch Vol. 7 (1&2) 2005: pp. 34-42