The effect of gibberellic acid and indoleacetic acid on sugarcane development with particular reference to pollen viability.

Abstract

The effects of two plant growth hormones, Gibberellic Acid (GA3) and Indoleacetic Acid (IAA), on growth and pollen fertility in sugar-cane (Var. Co 421) have been investigated. Pollen fertility was assessed by the Standard Staining methods and pollen germination in vitro. Gibberellic Acid caused stem elongation, delayed arrow emergence and lowered pollen fertility. 200 ppm was found to be the optimum concentration. This acid did not have any effect on brix. IAA, in contrast, had no effect on stem elongation but hastened arrow emergence and promoted pollen fertility. 100 ppm was found to be the optimums concentration in causing an increase in pollen fertility. However, it also had no effect on brix. Pollen staining (as an indicator of maleness) and pollen germination in vitro (as indicator of viability) showed a significant positive cor-relation (r=0.92). Brix and pollen viability in contrast did not show a significant correlation (r=0.09).