Evaluation of intensity and duration of seed dormancy in a recombinant inbred population derived from Spanish bunch genotypes

Pre- harvest sprouting in groundnut (Arachis hypogaea L.) seeds belonging to subspeciesjastigiara (Spanish bunch) is undes irabl e. Since it leads to in vitro germination resulting in substantial loss of seeds, both in quantity and quality. A short peri od of dormancy is therefore des irable in the sub-species to reduce such losses. Evaluati on of fresh seed dormancy was conducted for two seasons to determine the intensity and duration of dormancy in recombinant inbred population with 268 RILs developed from crosses involving moderately dormant (GPBD-4) and non-dormant (TAG-24) parents. The intensity of dormancy ranged from o to 100% in summer season while 0 to 90% in kharifseason. There was large vatiation in the intensity of dormancy whi ch could be related to genetic di fferences between the entries tested. RIL nos. 165, 259, 160, 172,209,254,2 13,247, and 248 recorded very high values (> 70 %) of intensity of dormancy in both the seasons. The vari ation for dormancy in terms of duration as revealed by germination of 70% (G 70 estimates) was subsequently large as compared to the intensity of dormancy among the RILs. The RIL nos. 5, 40, 84, 165, 183,209,2 13, 248, 254,259 and 265 were found to have more than two weeks of dormancy (based on G70 count) in both the seasons. These dormant lines can be utilized in breeding for fresh seed dormancy under Spani sh background.