Gibberellin sensitivity study shows key insights into the GA3 pathway in a semi-dwarf rice mutant of improved white Ponni

Abstract

Improved White Ponni (IWP) is a popular rice variety in south India. We have developed WP-22-2, a semi-dwarf mutant of Improved White Ponni through gamma-ray induced mutation breeding. Gibberellin sensitivity of the mutant was studied by spraying 50 μM GA3 hormone on ten days old seedlings and after three days, seedling height, 1st internode and 2nd leaf lengths were measured. The variances between the treatments were compared using Student’s t-test. The IWP was 2.54 cm taller than the untreated mutant. The 1st internode length between the two varied with high significance (P = .003). The GA3 treatment has increased the seedling height of the mutant 6.0 cm in three days. The reversion of plant height in the mutant showed that the mutations in the GA3 pathway have caused defective gibberellin production which ultimately reduced the plant height in the mutant.