Climate-smart varieties, water-saving techniques key to growing Asia’s future rice

Published on Wednesday, 14 October 2015

Published by Arvind Kumar on Wednesday, 14 October 2015

A rice farmer in Quang Tri province, Viet Nam.
A rice farmer in Quang Tri province, Viet Nam.

In the face of climate change-induced water shortage in Asia’s rice production areas, farmers are struggling to figure out how to grow more rice with less water to ensure food security in the region.Rice, the staple food crop for half of the world’s population, is grown on about 160 million hectares around the world, with 90% of the grains being grown and consumed in Asia. Using conventional rice production (puddled transplanted), 2,500 liters of water is needed to produce a kilogram of rice, on average – 2–3 times more water than the amount needed to grow other cereals. Nearly half of diverted fresh water in the region is used to irrigate rice fields.However, between 1950 and 2005, available water per capita in Asia has decreased by between 37% and 76%, depending on location. Climate change, booming industrial activity, and expanding residential areas to house the increasing population all make the situation more acute. The share of agriculture in Asia’s freshwater resources has also seen a sharp decline.Sustained rice cultivation likewise suffers from shortage of labor needed to grow rice under puddled transplanted conditions, as rural folk move from farming to industry and other non-farm work in pursuit of higher income in urban areas. Agricultural operations such as field preparation and transplanting are quite labor-intensive, and farm labor is becoming increasingly scarce and expensive, making rice production less profitable.To help address these challenges, the International Rice Research Institute (IRRI) is working on initiatives such as, development of climate-adapted rice varieties and large-scale multiplication and dissemination of seeds; water-saving techniques such as “aerobic rice”—a technology for moderate yield capacity under direct-seeded situations—and "alternate wetting and drying” (AWD) to replace  high-yielding transplanted rice.Testing at IRRI headquarters in the Philippines and field tests in Bangladesh and India have shown that “safe AWD” (when water level is allowed to recede to a level 6 inches below the soil surface) results in 15–20% water savings without compromise on yield. Trials on aerobic rice have demonstrated water savings of 30–35% and, as it uses direct seeding, farmers can save on labor cost compared with puddled transplanted rice. Research conducted by IRRI from 2007 to 2010 led to the development of several varieties and promising breeding lines for aerobic and AWD conditions in India, Bangladesh, and Nepal. The work was supported by ADB and carried out in cooperation with national partners in these three countries and Pakistan. Different varieties were recommended for aerobic situations in each country, and aerobic rice-based crop rotations that have shown high productivity were identified.

With financial support from ADB, IRRI started in 2014 a project to develop and disseminate second-generation high-yielding climate-resilient rice varieties for water-short areas in India, Nepal, Bangladesh, Lao PDR, Cambodia, and the Philippines. The project aims not only to enhance rice production and increase the incomes of farmers in water- and labor-short regions of South and Southeast Asia, but to also build capacity on developing and disseminating cultivars better suited to each area. In the second phase of the project, water-short areas suitable for the use of aerobic rice and AWD will be identified, to precede targeted seed distribution that will directly reach at least 10,000 farmers in each country.

IRRI and ADB will continue to work together on similar projects to develop climate-resilient, water-saving techniques and share them with rice farmers to ensure a sustainable supply of Asia’s staple food. 

Under IRRI’s breeding program in Cambodia over the past three years, six aerobic rice lines that have shown promising yield performance; resistance to blast, bacterial leaf blight, and brown leaf spot; slender grain; and low chalkiness were identified from among 255 aerobic and rain-fed lines from IRRI. In Lao PDR, evaluation of IRRI’s aerobic rice lines resulted in the identification of four lines with promising performance. The use of AWD as well as aerobic rice have had positive results in farmers’ fields, with identified breeding lines yielding 10–30% more despite use of less water.