Studies on the effect of gibberellic acid on the growth and yield in rice (Oryza sativa, L)

Abstract

The present investigation is undertaken to study the effects of gibberellic acid on the cereal, rice (Oryza sativa. L). The hormone was used at concentrations of 25,50,75, 100 and 125 ppm., as spray application on the 21 days old seedlings. Three stages of applications namely spraying once in a week , once in two weeks and once in three weeks were tried. A pot culture experiment was conducted adopting a randomised block design. The effect of gibberellic acid on the height of plants, number of tillers, time of flowering, fresh and dry weight of stem, length of the ear heads, number of leaves , dry weight of the roots and the yield were studied. Of these only height of the plants was influenced significantly by the treatments. Marked shoot elongation was observed in the gibberellic acid treated plants. The maximum response was at the level of 100 ppm. Weekly spraying is better than spraying once in two weeks and once in three weeks.