June 15, 2005
Source: Business Standard, New Delhi, 14 Jun 2005 [edited]

Is the wheat revolution dying?

The annual growth rate in wheat production dropped from a healthy 3.57 percent in the 1980s to 2.11 percent in the 1990s and below one percent in the current decade. After hitting a peak of 76 million tons in 2000, wheat
harvest has been hovering around 72 to 74 million tons, according to the Food Corporation of India (FCI). In fact, the erosion of FCI's stock need not be viewed with concern, as it has been the result of a deliberate move to shed burdensome inventories through subsidized exports and liberal use of grains in welfare and food-for-work programs.

The relatively lower wheat procurement also should not be a cause for much concern. It only reflects higher purchases by private trade and withholding of some stocks by big farmers in anticipation of better prices in lean
seasons. These stocks have to, sooner or later, come out in the market.

However, the below-anticipation wheat harvest for the 5th successive year should be a matter of real discomfiture and should make wheat scientists and policy makers sit up.

The agriculture ministry, which had earlier reckoned the wheat harvest to be around 74.05 million tons, has scaled it down to 73.5 million tons. Wheat experts, who were hoping to bag a harvest of around 75 million tons, now feel that the production would be just around 73 million tons. The wheat trade, on the other hand, is projecting a still lower output of around 71 to 72 million tons.

Some causes for a low wheat yield have, of course, been identified. Noted wheat expert and Indian Agriculture Research Institute (IARI) director S. Nagarajan believes that the unexpected emergence of 2 diseases so close to
ripening of the crop is responsible for yield drop.

Black rust, a dreaded plant disease, resurfaced after over 10 years, affecting the predominant cultivar PBW-343 in Punjab and adjoining areas when the crop was heading towards maturity. Another relatively lesser-known disease, called head scab, struck the durum wheat (hard wheat used for making noodles and pasta products) around the same time to cause yield loss. This disease is endemic to North America and has not been reported in
India in the recent past.

Poor wheat yields in earlier years of this decade had been caused largely by unfavorable climatic factors, such as untimely rains or temperature rise. Moreover, 2 dreaded weeds, _Phalaris minor_ and wild oats, had posed a formidable danger to wheat cultivation. But fortunately, their control was discovered through pesticides and agronomic management.

More recently, rust diseases -- yellow, brown and black rusts -- spread like an epidemic throughout the northwestern wheat belt. Fortunately, they were tamed by breeding rust-resistant varieties and breaking the disease cycle by saturating the wheat-growing southern hilly region with rust-immune varieties. That was the region where the rust pathogen used to survive in summer when the crop was not being grown in the plains.

Wheat, being a non-monsoon-dependent winter season cereal, is critical for the country's food security, and any deceleration in its production growth is unwarranted. Wheat output needs to grow annually by at least 2.5 percent
to keep pace with the rise in demand.

[Byline: Surinder Sud]

--
ProMED-mail
<promed@promedmail.org>

[The major wheat-producing countries of northern Asia are India, Pakistan, Nepal, Bangladesh and Myanmar in order of importance. Most of the wheat is produced in the Ganges and Nurmada basins of India and the Indus River Valley of Pakistan. Much of the wheat in India and Pakistan is irrigated, while in Nepal and Bangladesh it is mostly rain fed. White grain cultivars are preferred and are primarily of spring habit, but are usually sown in
November and December and harvested in April and May.

Consumption is highest in Pakistan at 141 kg/caput and lowest in Myanmar at 3 kg/caput. World production as of 2004 is 624 093 306 metric tons. India is one of the largest wheat producers in the world, with about 25 million
ha [1 hectare= 10,000 square meters] under production and averaging almost 60 million tons in recent years. More than 90 percent of the area is sown to bread wheat, which is grown throughout the country. Durum or macaroni wheat accounts for around 8 percent of the area. The crop is grown in most parts of the country, but nearly 70 percent lies in the northern plains and 20 percent in central India.

A rice-wheat rotation is the dominant cropping sequence. Crops other than rice that precede wheat are also used, particularly in the central and southern regions. In the large wheat research and development program in India, much germplasm is screened for important biotic and abiotic stresses. Important biotic pests include the rusts, Karnal bunt, foliar blight, powdery mildew, common bunt, flag smut and nematode and insect pests. Salt, heat and drought are the major abiotic stresses. Large amounts of NPK fertilizers are used to produce the wheat crop in India.

Over the past 3 decades, increased agricultural productivity in Pakistan occurred largely due to the deployment of high-yielding cultivars, increased fertilizer use and greater availability of irrigation water. By the mid-1980s, semidwarf wheat cultivars had been adopted on almost all irrigated land, and over 100 kg/ha on average of fertilizer was being applied to wheat. Pakistan production averaged 16.1 million tons on 8.2 million ha each year during the period 1993-1995. Rice-wheat, berseem-wheat and cotton-wheat are major systems of intense cropping in Pakistan.

Wheat scab (also known as Fusarium head blight) is caused by the fungus _Fusarium graminearum_. It is a common problem in Europe, Asia, South Africa, and the Midwestern and Eastern U.S.A. Scab severity is very erratic
and depends heavily on wet weather conditions. Scab often causes reduction in test weight, sometimes down to near 50 lb/bu. In addition, scabby kernels count as "damaged" in the grading process. Although scabby wheat is
often very good, it may contain the mycotoxins DON (vomitoxin) and zearalenone (an estrogen analog). Swine are most sensitive to scabby wheat mycotoxins, and as little as one ppm of DON can significantly reduce daily
weight gains in pigs. Higher concentrations result in feed refusal and vomiting. Swine reproduction is also sensitive to disruption by the zearalenone mycotoxin. Non-breeding cattle and poultry seem to tolerate both toxins better than swine.

Links:
<http://www.cimmyt.org/worldwide/CIMMYT_Regions/CIMMYT_Asia/cimmyt_in_asia/cimmyt_in_asia.htm>
<http://www.tribuneindia.com/2005/20050318/nation.htm>
<http://www.fao.org/documents/show_cdr.asp?url_file=/DOCREP/006/Y4011E/y4011e04.htm>
<http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Scab.asp>
- Mod.DH]