Effect of indole-3-acetic acid on germination and seedling growth of Vigna unguiculata (L) Walp and Phaseolus vulgaris species

Abstract

The effect of Indole-3- acetic acid (IAA) on germination and seedling growth of two bean species naely Vigna unguiculata L. Walp and Phaseolus vulgaris was carried out. The germination percentage (FGP) was highest in 0ppm (80%) of V. unguiculata but highest in 100ppm (43.33%) of P. vulgaris. Germination rate index (GRI) was maximum in 0ppm (63.33%/day) followed by 100ppm (35.83%/day) while the minimum value was in 200ppm (6.67%/day) in V. unguiculata. For P. vulgaris, the maximum was 26.67%/day in 50ppm while the minimum was 12.50%/day in 0ppm. Germination first occurred 1 day after planting in 50ppm, 100ppm, 150ppm and 0ppm for V. unguiculata but 2 days after planting in 200ppm. For P. vulgaris, germination was first recorded in 50ppm, 150ppm, 200ppm and 0ppm but 2 days after planting in 100ppm. Germination was last reported 2 - 4 days after planting in both species of beans. The time spread of germination ranged between 0 – 3 days in V. unguiculata and P. vulgaris. The radial length was 16.12mm in 0ppm, 9.86mm in 50ppm and minimum 6.20mm in 200ppm for V. unguiculata while P. vulgaris 7.33mm in 100ppm, 7mm in 0ppm and least 6.11mm in 200ppm. In V. unguiculata, the low concentration of IAA enhances germination while high concentration tends to inhibit germination. In P. vulgaris, pre-soaking of the seed have no effect on the germination as less than 50% of the seeds germinated. The radicle length showed that P. vulgaris. Further studies should be done using other growth hormone on P. vulgaris to improve its germination and seedling growth.