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CESD Seminar

Friday, April 07, 2017, 01:15pm - 02:15pm


Improved weed management and crop establishment in direct-seeded systems using anaerobic germination-tolerant rice (Oryza sativa L.) genotypes

B.S. Chamara
Ph.D. Scholar, Weed Science
Crop and Environmental Sciences Division

Improving rice production technologies through efficient resource use is critical in keeping the food supply sufficient to feed increasing populations and under a changing and variable climate. Direct-seeded rice (DSR) is one such strategy and has evolved as a feasible alternative to the conventional puddled transplanted rice. Two major constraints in DSR, however, are (A) poor and uneven crop establishment due to water logging/flooding soon after seeding, and (B) high weed infestation, both of which result in significant yield loss unless managed properly. Farmers have primarily used herbicides in DSR systems to improve the timeliness of weed control and to overcome labor bottlenecks. Although the use of herbicides greatly minimizes weed competition, it may not provide season-long weed control when applied alone. In addition, over-dependence on the use of herbicides poses both economic and environmental risks, including the evolution of herbicide resistance in weed species. Hence, integrated weed management becomes a key approach to sustainable weed control in DSR systems. Water management, on the other hand, is the most effective cultural weed management strategy in any weed control program. Flooding the field soon after direct seeding creates an anaerobic environment that helps to manage weeds effectively during the early stages of crop growth. However, flooding also reduces the germination of rice seeds, as modern rice genotypes are unable to withstand anaerobic conditions. The International Rice Research Institute (IRRI) has thus developed anaerobic germination-tolerant (AG) rice genotypes, which may help in overcoming both issues of poor crop establishment and high weed infestations in DSR under flooded conditions. A series of studies was carried out on developing effective crop establishment and weed management techniques in wet- and dry-DSR systems involving AG genotypes, under screenhouse and field conditions. In this seminar, key findings including crop establishment and growth, weed control, weed population dynamic, associated problems in each system under anaerobic conditions, and successes and failures will be presented.


CESD Conference Rm 1, DL Umali Bldg.