Screening of thirteen salt-tolerant cowpea (Vigna unguiculata (L.) Walp) accessions during germination

Soil salinity is one of the most important production constraints. Many studies have attempted to find a solution to this problem. The general objective of this study was to evaluate the influence of salinity on cowpea seed germination. Two salt concentrations (0 control and 150 µM NaCl) and thirteen varieties were tested in the laboratory following randomized complete block design with three replicates per treatment. The number of germinated seeds was recorded every until the eighth day, when the germination parameters were evaluated. The results indicate that the germination percentage (GP), the germination index, the seed vigour index, the germination vigour index, the velocity coefficient and the emergence rate decreased significantly (p˂0.05) in the saline treatment, while the latency time, the 50% germination time (T) and mean germination time increased. Thus, on day 8, the PG of V1(IR15M02) was 83.33% and 43.33% for 0 and 150 µM respectively. The T increased by 55.67% to 150 µM compared to 0 µM in V11(LORI). Seedling length decreased from 8.30 cm in control to 2.00 cm at 150 µM in V10(LOCAL3GG). The classification of varieties resulted in four groups: group 1 consisting of susceptible V1(IR15M02), V6(IR15MA33), V10(LOCAL3GG), V11(LORI) and V12(MTA22); group 2 corresponding to moderately susceptible V2(IR16MAK), V4(TILIGRE), V8(LOCAL3PG) and V9(BRI); group 3 comprising moderately tolerant V7(LOCAL3fbt) and group 4 including V3(WIBALI), V5(IR16MAP) and V13(KOMCALLE), which are tolerant to salinity at the germination stage. The varieties in groups 3 and 4 can therefore be recommended for their tolerance to salinity during germination.