Abstract

Submergence tolerance is an important agronomic trait for rice grown in eastern India; where flash flooding occurs frequently and unpredictably during the monsoons. Generation of somaclones for the two submergence tolerant rice cultivar FR13A and FR43B through gamma irradiation and molecular analysis of the somaclones for the variation in the pyruvate decarboxylase (pdc) gene was investigated. FR43B showed a relatively higher frequency of callus induction than FR13A. However, the % regeneration of somaclones in both the genotypes gradually decreased with increase in the level of radiation dose. The somaclones of FR43B showed greater tolerance to submergence than FR13A. The doses/concentration of GR 20Kr and GR 25Kr irradiation increased the morphological and yield parameters over those in controls. All the somaclones with the pdc1 were tolerant to submergence irrespective of the gamma dose there by suggesting that pdc1 gene is directly linked to submergence tolerance in rice.

Key words: Pyruvate decarboxylase, gamma irradiation, callus induction frequency, submergence.