Effect of IAA and BAP application in varying concentration on seed yield and oil quality of Guizotia abyssinica (L.f.) Cass

Abstract

A low production of oil seed crops, paired with their increased demand, has become a challenge for the edible oil industry in India. Guizotia abyssinica (L.f.) Cass. (niger seed plant) is an annual, dicotyledonous, multipurpose oil seed crop belonging to the family of Asteraceae. Although this plant produces abundant flowers, it fails to produce mature seeds with vigor due to poor vascularization. We investigated the effects of the plant growth-promoting hormone auxin, indole-3-acetic acid (IAA), and the cytokinin, 6-benzyl aminopurine (BAP) individually and together on the growth and oil quality of niger in lateritic soil. Pot experiments were conducted during the wet seasons of 2014 and 2015 in subtropical eastern India. The plants were sprayed with 25, 50, 75, and 100 mg L⁻¹ each of IAA and BAP, 50, 75, and 100 mg L⁻¹ of IAA + BAP, or water (control). When applied individually—IAA or BAP at 75 mg L⁻¹ (I₇₅B₀ or I₀B₇₅)—the biomass production was maximized. The combination of IAA (50 mg L⁻¹) and BAP (100 mg L⁻¹; I₅₀B₁₀₀) yielded significantly high biomass (38 and 40 g plant⁻¹) and seed yield (13.24 and 12.67 g plant⁻¹) in 2014 and 2015, respectively. The most effective combinations for increasing niger seed oleic acid content were I₅₀B₁₀₀ and I₅₀B₇₅ as compared to other combinations of growth hormone. These results suggest that exogenous phytohormones can improve the seed yield and oil quality of niger seed plants in acid lateritic soil.