physiological biochemical and molecular basis of seed dormancy in rice

Abstract

ABSTRACT newlinePHYSIOLOGICAL, BIOCHEMICAL AND MOLECULAR BASIS OF SEED newlineDORMANCY IN RICE newlineBy newlineR. SIVAKALAI newlineDegree : Doctor of Philosophy (Agriculture) in newlineSeed Science and Technology newlineChairman : Dr. J. RENUGADEVI, Ph.D. newlineProfessor newlineDepartment of Seed Science and Technology newlineTamil Nadu Agricultural University newlineCoimbatore 641 003 newline2018 newlineStudies were carried out in twelve rice varieties viz., ADT 36, ADT 37, ADT 38, newlineADT 40, ADT 49, CO 43, CO 47, CO (R) 48, CO (R) 49,CO (R) 50, CO(R) 51and newlineN 22 to determine the stage of acquiring seed dormancy; to identify the factors causing newlinedormancy and methods to overcome seed dormancy; to study the protein profile of rice newlineseeds exhibiting dormancy; to standardize dormancy induction treatments and to study newlinethe storage potential of the dormant varieties of rice under the cold storage conditions. newlineA study on stage of seed development of acquiring seed dormancy revealed that newlinebased on the observations on days to initiation of flowering, 50 per cent flowering, newlinephysiological maturity and harvestable maturity, the varieties viz., ADT 36, ADT 37, newlineCO 51 and N 22 showed earliness for flowering and attainment of maturity than the newlineremaining varieties viz., ADT 38, ADT 40, ADT 49, CO 43, CO (R) 48, CO (R) 49, newlineCO (R) 50). The observations on seed germination at physiological maturity and newlineharvestable maturity stages revealed variation among the varieties, indicating that the newlinevarieties viz., ADT 36 ADT 37, ADT 38 and N 22 were dormant by recording nil newlinegermination with 100 per cent fresh ungerminated seeds and other varieties viz., ADT 40, newlineADT 49, CO 43, CO 47, CO (R) 48, CO (R) 49 and CO 51 were found to be non newlinedormant. With reference to variety CO (R) 50 which recorded very low germination of newline15 per cent at physiological maturity and 18 per cent at harvestable maturity indicated the newlinepresence of dormancy in variety CO (R) 50. The observation on imbibition rate indicated newlinethat the dormant varieties recorded low imbibition rate than the non dormant varieties. newlineThe observed biochemical parameters rev