Variability in seed germination and dormancy of Indian weedy rice

Abstract

Seed dormancy is an adoptive trait of weedy rice to persist in rice production system. Weedy races and wild relatives of rice exhibit variation in seed dormancy, which allows weedy rice to escape weed management practices, and increases the flowering synchronization pattern resulting in gene flow between weedy and cultivated rice. In this study, eighteen weedy rice morphotypes collected from different rice growing areas in India, along with two rice cultivars, were evaluated for their germination pattern across time. Weedy rice seed germination was recorded periodically at weekly intervals up to 35 weeks after sowing (WAS) under controlled conditions. Dormancy duration was computed and germination index was calculated at 27 WAS. Significant variability was observed in germination pattern among the weedy rice morphotypes studied. The weedy rice morphotypes collected from Uttar Pradesh (T68) attained 50% germination after a maximum duration of 13.5 WAS, while five morphotypes of weedy rice remained ungerminated at 3 WAS. Seven weedy rice morphotypes germinated at 3 WAS at which both the rice cultivars (BPT 5204 and Pusa 1101) have germinated (96.7 and 83.3%, respectively). Two weedy rice morphotypes had highest germination percentage (98.3%) at 35 WAS, while least (21%) was recorded with morphotype collected from Chhattisgarh (T41). This study indicated the existence of high degree of dormancy in weedy rice morphotypes. The findings of this study might be helpful for agronomists and farmers to develop and implement effective weedy rice management strategies at different rice production systems in India.