PHYSIOLOGICAL AND MORPHOLOGICAL RESPONSES OF FIVE RICE VARIETIES TO COLD STRESS AT SEEDLING STAGE

Abstract

A field experiment was carried out to investigate the physio-morphological characteristics of seedlings offive rice cultivars for screening cold survival during low temperature in Northwest of Bangladesh. The test rice varieties were BINA dhan-6, BRRI dhan26, BRRIdhan 28, BRRI dhan 29, BRRI dhan50. The experiment was laid out in randomized complete block design (RCBD) with three replications. The leaf proline, chlorophyll content, relative water content (RWC), protein, starch, seedling shoot length, shoot weight and root length,root weight, total biomass, and seed germination rate were investigated. Results indicate that rice varieties has significant effect on the parameters studied. BRRI dhan 28 synthesized highest amount of proline (1.259 mg g''), chlorophyll-a (2.630 mg g") , chlorophyll-b (0.847 mg g’'), relative water content (93.33 mg g'), protine (14%), and starch (28.21%) content, seed germination (90.67%), shoot (0.021) and root (0.025) dry weight. The performance of varieties at low temperature was of the order of BRRI dhan28> BRRI dhan29> BRRI dhan26> BINA dhan6> BRRI dhan50. The overall results of the study infers that BRRI dhan28 showed the better survival potentiality during cold temperature by oversynthesizing proline, chlorophyll and other physio-morphological parameters.