A.R. NIRMAL KUMAR*, C. VIJAYALAKSHMI AND D. VIJAYALAKSHMI
Department of Crop Physiology, RARS, ANGRAU, Tirupati – 517 502, Chittoor Dt., A.P.
Floral anatomy, which determines the yield in rice, is greatly affected by heat and drought stresses during reproductive phenophase. Trials under controlled environmental conditions and field experiments under rain out shelter facility were carried out to elucidate information on floral behavior of rice genotypes to combined heat and drought stresses. Three rice (Oryza sativa L.) genotypes namely ADT 43, TKM 9 and N 22 which differed in their tolerance behavior to heat and drought stress but had similar phenology were taken and exposed to combined stresses of heat and drought at panicle initiation (PI) and anthesis stages. Exposure of plants to combined stresses at anthesis resulted in early flowering, reduced anther length, width, pollen viability and stigma receptivity. Stress imposed at anthesis caused greater reduction in anther length compared to stress imposed at panicle initiation. The genotype N 22 was observed to maintain larger anther length and width compared to other genotypes. Pollen viability and stigma receptivity were assessed microscopically and it was found that N 22 registered more number of germinated pollen on stigma while it was less in ADT 43. The genotype N 22 was found to be tolerant with superior floral characters.
Anther, Drought, Heat, Oryza sativa, Pollen and Stigma