Chromosome Observation of Rice Root Tip and Effect of Callus Colour Variation and Texture in Different Colchicine Concentrations on the Induction of Rice Polyploids

Abstract

The abiotic stresses course major environmental factors that determine the most serious yield reduction in rice (Oryza sativa L.). The abiotic stresses tolerant ability can be improved by changing typical chromosome number of plants. The objectives of the studies were to evaluate the performance of callus of rice cultivars (Suwadel and Sulaai) for different Colchicine concentrations to produce polyploidy for enhance tolerant characteristics to drought and salinity stresses. Surface sterilized seeds were introduced to Murashige and Skoog (MS) basal medium with hormone 2mgL-1 2,4-D (2, 4-dichlorophenoxyacetic acid) and 0.1 mgL-1 BAP (6-benzylamino purine) for callus induction. Callus of 0.5cm 2 from rice cultivars introduced to different Colchicine concentrations (0, 30, 60, 90 and 120 mgL-1) and different time durations (12, 24 and 78 hours). Treated callus were introduced to shoot regeneration on MS medium with 0.1mgL-1 IAA (Indole acetic acid) and 2mgL-1 BAP. Colour, texture and regeneration ability of callus were recorded after one month. Completely Randomized Design (CRD) with five replicates was used for study. Statistical analysis was performed with Duncan's multiple range tests using SAS software (version 9.1.3). Results showed that callus treated from Colchicine 30, 60, 90 and 120 mgL-1 in 12 hours and, 30, 60, 90 mgL-1 in 24 hours have potential to survive. Increasing Colchicine concentration and time duration showed that regeneration ability of callus reduced in selected rice varieties.