Effects of pendimethalin on pod attributes of five elite accessions of cowpea

Abstract

A field study on the effects of pre- and post-emergence application of herbicide (pendimethalin) on the reproductive yield of five accessions of cowpea (TVu-9092, TVu-16265, TVu-16320, TVu-16323 and TVu-16421) was conducted between June and August, 2018. Pendimethalin was applied both as pre- and early post-emergence herbicide (PE and EPOE) and followed by hand weeding at 4 and 8 weeks after sowing (WAS). Number of pods per plant was highest in TVu-9092 treated with 0.125 kg/ha PE pendimethalin (19.33) and 0.250 kg/ha pendimethalin EPOE application (19.00). Highest pod diameter in PE treatment was produced in TVu-16320 with 0.25 kg/ha pendimethalin (7.55 mm) and TVu-16323 with 0.125 kg/ha pendimethalin produced the highest pod diameter (7.74 mm) in the EPOE treatment. Highest pod length in the PE treatment was produced in TVu-9092 with 0.125 kg/ha, while TVu-9092 without pendimethalin produced the highest pod length (30.00 cm) in the EPOE treatment. In the PE treatment, TVu-16265 and TVu-9092 treated with 0.125 kg/ha had the highest (2.99 g) and lowest empty pod weights (1.70 g) respectively. In the EPOE treatment, the highest empty pod weight (3.01 g) was produced in TVu-16265 with 0.125 kg/ha pendimethalin while the control of TVu-16320 recorded the lowest empty pod weight (2.03 g). The highest of 100 seeds weight (14.91 g) was produced in TVu-16421 with 0.125 kg/ha pendimethalin PE treatment and lowest (9.26 g) was obtained in the untreated control of TVu-16323. In the post-emergence treatment, the lowest 100 seeds weight (8.88 g) was obtained in TVu-16320 with 0.125 kg/ha. Highest weight per pod in the PE and EPOE application was obtained in untreated control with TVu-9092 (10.47 g), while the lowest weight per pod (3.22 g) was in TVu-16265 with 0.125 kg/ha EPOE application. The study concluded that pendimethalin application as pre- and early post-emergence herbicide at low and high concentrations produced varying effects on pod attributes among the accessions of cowpea.