THE INFLUENCE OF SEED PRIMING ON WEED SUPPRESSION IN AEROBIC RICE

Aerobic rice refers to growing dry direct seeded rice in non-saturated soils without any standing water layer. Aerobic rice cultivation is a promising approach to cope with water scarcity. However, this method of cultivation has suffered from increased problems due to weeds and from poor stand establishment. Seed priming (controlled moisture addition technique allowing seeds to be hydrated partially without radicle emergence) reduces emergence time, boosts germination percentage and favors synchronized emergence, this might have a great influence on weed suppression, seedling stand and yield. The present study was, therefore, designed to explore the possibility of adopting seed priming technique for suppressing weeds in aerobic rice. The experiment was conducted at Universiti Putra Malaysia, Malaysia with aerobic rice germplasm AERON 1 with four priming techniques: hydropriming, hardening, Zappa® priming and untreated control; and two levels of weed control: weed free and weedy. Seed priming significantly improved germination attributes, weed suppressive ability and yield of rice, whilst unprimed control exhibited inconsistent germination, poor seedling establishment and less weed competitiveness resulting lower yield. Priming increased germination percentage by 6% and reduced mean germination time by 2 days. Priming enhanced the germination index and seedling vigor index to a great extent. Reduction in weed dry matter due to priming ranged from 22 to 27 % compared to control. A positive influence of priming was also reflected in rice yield. Weed inflicted relative yield loss was curtailed by 10% as a consequence of seed priming. Among different priming techniques, priming with Zappa® solution was the best and thus may be considered as a pragmatic tool for sustainable weed management in aerobic rice.