Maize is a primary food crop in Bhutan after rice, and it ranks first among food crops in terms of both extent of area cultivated and total production. It plays a critical role in household food security. It is estimated that 80% (of 353 million nu annually in 2006) of the total production is consumed at the household level by farmers. About 6% is sold, providing an important source of household income. The rest is used as seed, processed into different products and fed to the livestock. Maize export is negligible.
Cultivation ranges from less than 300 m asl up to about 3,000 m asl. This covers three broad production zones:
- Sub-tropical maize production zone 1 (< 1200 m asl) or low altitudes;
- Sub-tropical maize production zone II (1200-1800 m asl) or mid altitudes; and the
- Highland maize production zone (> 1800 m asl).
These different production zones vary widely in their production potentials and constraints.
Several generalist insect pests can sometimes cause problems. Of more significance are two diseases, gray leaf spot and turcicum leaf blight. Gray leaf spot only emerged as a serious issue in Bhutan in around 2006, and subsequently spread rapidly. A major plant selection programme was undertaken resulting in the release of GLS resistant maize varieties that are now widely used in susceptible areas.