IN VITRO PLANT REGENERATION IN LOCAL AUS RICE THROUGH MATURED SEED CULTURE

Abstract

An investigation was carried out to decipher the effect of genotypes and concentrations of growth regulators for callus induction and subsequent plant regeneration from mature seeds of rice. Two local rice cultivars viz. Nayanmony and Kalomona and two growth regulators viz. 2, 4-D and NAA were used to evaluate their performance. The seeds were cultured under aseptic condition onto MS basal medium at varying concentrations and combinations of 2, 4-D (1.0, 1.5 and 2.0 mgL- 1) and NAA (0.0, 0.5 and 1.0 mgL-1) for callus induction. For plant regeneration MS medium fortified with 0.5 mgL- 1 NAA and 3.0 mgL-1 BAP was applied. Between the two cultivars Nayanmony showed better responses in callus induction frequency (91.38%), weight of callus (0.90 g)as well as diameter of callus (7.48 mm). Among the combinations 2, 4-D (1.5 mgL-1) alone produced the best callus (95.16%) and the highest weight of callus (1.88 g) but diameter of callus (8.27 mm) was the highest from 2, 4-D 1.0 mgL-1 +0.5 mgL-1 NAA. It was observed that both genotype and growth regulator significantly affected callus induction and plant regeneration. The medium supplemented with 2, 4-D 1.5 mgL-1 + NAA0.0 mgL-1 exhibited better performance in callus induction (99.33%) and weight of callus (1.92 g) in cultivar Nayanmony whereas Kalomona was better for diameter of callus (8.38 mm) at 2, 4-D 1.0 mgL-1 + NAA0.5 mgL-1. The cultivar Nayanmony performed better regarding plant regeneration (88.15%) compared to Kalomona (86.67%). Plantlets derived from the 2, 4-D 1.5 mgL-1+ NAA 0.0 mgL-1 showed the best results for survival. Therefore, it is suggested that application of MS medium supplemented with 2,4-D 1.5 mgL-1 and NAA 0.0 mgL-1 is advantageous to accomplish overall efficiency of callus induction, subsequent plant regeneration and survival from seeds of Nayanmony cultivars. Thus, selection of better responsive cultivar like Nayanmony and MS medium fortified with 1.5 to 2.0 mgL-1 2, 4-D would be beneficial in transformation attempts to improve the crop.