In Pakistan, wheat being the staple diet is the most important crop and cultivated on the largest acreages in almost every part of the country. It contributes 14.4 percent to the value added in agriculture and 3.0 percent to GDP. Over the past three decades, increased agricultural productivity occurred largely due to the deployment of high-yielding cultivars and increased fertilizer use. With the introduction of semi-dwarf wheat cultivars, wheat productivity has been increased in all the major cropping systems representing the diverse and varying agro-ecological conditions.
WHEAT IN PAKISTAN
Pakistan has been divided into ten production zones because of great agro ecological areas where wheat is grown. The zoning is mainly based on cropping pattern, disease prevalence and climatological factors. However, production zones need to be revisited.
In Pakistan, wheat is grown in different cropping systems, such as; cotton – wheat, rice – wheat, sugarcane – wheat, maize – wheat, fallow – wheat. Of these, Cotton-Wheat and Rice-Wheat systems together account about 60% of the total wheat area whereas rain-fed wheat covers more than 1.50 m ha area. Rotations with Maize-Sugarcane, Pulses and fallow are also important.
Improved semi-dwarf wheat cultivars available in Pakistan have genetic yield potential of 6-8 t/ ha whereas our national average yields are about 2.7 t/ha. A large number of experiment stations and on-farm demonstrations have repeatedly shown high yield potential of the varieties. There are progressive farmers of irrigated area who are harvesting 6 to 7 tonnes yield per hectare. However, farmers yield ranges 0.5 to 1.3 tones per hectare depending on the amount of rainfall in rainfed areas and in irrigated areas it ranges from 2.5 to 3 tones per hectare depending upon the amount of water available and other factors.
Factors contributing towards yield gap
The above discussion concludes that there is around 60% yield gap in wheat, which needs to be narrowed. Wheat production in the country, however, has been well below potential and variable. The major reasons for low productivity and instability includes: delayed harvesting of kharif crops like cotton, sugarcane and rice, and consequent late planting of wheat, non availability of improved inputs like seed, inefficient fertilizer use, weed infestation, shortage of irrigation water, drought in rainfed and terminal heat stress, soil degradation, inefficient extension services. Moreover, farmers are not aware of modern technologies because of weak extension services system.
WHEAT RESEARCH AND DEVELOPMENT IN PAKISTAN
In 1977-78 a disease epidemic of yellow rust inflicted heavy losses to the wheat production in the country. As a consequence, it was realized that there is need of strengthening the agricultural research in the country. Therefore, the government decided to reactivate the Pakistan Agricultural Research Council (PARC) as the coordinating body for agricultural research programs on major crops in the provinces. Since the inception of Wheat, Barley and Triticale Program, considerable and continuous role has been played by it in conducting research and developmental activities to increase the production of wheat in different agro-ecological zones of Pakistan and thereby, increase farm income. The program adopts a multi-disciplinary approach in order to evolve stable, high yielding wheat varieties and also develop and update a package of crop management practices. The program has initiated following major activities to realize the increased wheat production in the country:
i Establishment of Research Collaboration/Linkages
Effective research linkages have been established three international wheat research centres and 26 national and provincial wheat research organizations.
ii Germplasm Acquisition, Evaluation and Distribution
This program has developed an organized system to introduce and distribute wheat germplasm to the breeders of the country belonging to different federal and provincial research organizations, after acquiring it from different international sources. Through this mechanism, high yield potential, disease resistance and good quality traits have been incorporated into new varieties.
iii National Uniform Testing and Variety Release
It is a network for evaluating the candidate lines in different agro-ecological zones developed by the breeders of both provincial and national Wheat research institutes under the supervision of National Coordinated Wheat Program. So far, more than 100 varieties have been released in the country through National Uniform Testing Program.
iv Annual Wheat Meeting
The Coordinated Wheat Programme of PARC plans Annual wheat Meeting every year. About 80 participants from 25 different research and extension institutions and international centres participate in this meeting where different research and production issues are discussed in detail. Moreover, achievements of different cooperating units are also presented along with next year’s plan of work. In the end, future strategies and recommendations are finalized to enhance the wheat production in Pakistan.
V. Wheat Traveling Seminar
Wheat Traveling Seminar is another useful activity of the Wheat Coordinated Programme of PARC which provides not only an opportunity to the wheat scientists to jointly assess the status of the standing wheat crop but also gives them opportunity to observe and interview the farmers and extension workers regarding their local problems. The National Uniform Wheat Yield Trials planted in different parts of the country are also evaluated and potential varieties identified. Above all, the seminar provides an opportunity for the scientists to identify priority research areas.
At present, the Wheat research programs are giving due emphasis on the following researchable areas:
Pakistan has been facing water shortages and drought conditions for the last several years due to lesser rains and high temperatures with the result wheat production both in irrigated and rainfed areas is being hampered. In order to minimize the effects of drought and high temperatures, drought and heat tolerant varieties need to be evolved in addition to the judicial use of available irrigation water.
Diseases, especially rusts (Stripe/Yellow Rust, Stem Rust, Leaf Rust and emerging scenario of Powdery Mildew) are major biotic stresses of wheat crop that inflict heavy losses when in epidemic form. Therefore, breeders and pathologists are given priority to develop disease resistant and high yielding varieties in order to cope with threats created by ever changing rust races by using approaches like durable resistance.
It is another menace to which wheat is exposed in saline areas of Pakistan. Therefore, there is need to evolve salt tolerant wheat varieties for such ecologies by introducing salt tolerant genes like BADH using novel breeding techniques.
Farmers generally plant wheat late in rice-wheat, sugarcane-wheat, and cotton-wheat areas of Pakistan due to late harvesting of these kharif crops which results in drastic low yields because the crop is exposed to heat stress at grain filling period leading to the formation of shriveled grain. Currently, only 20% of wheat is being planted at optimum planting time (15th October to 15th November). To achieve good yield, wheat sowing should be carried out well in time. Any delay in planting would reduce yield drastically. For example, wheat planted after 10th November would reduce the yield as high as 42 kg/ha/day (1% loss per day). There will be 8, 16, 32 and 50% reduction in wheat grain yield for each fortnightly after 10th November. In late-planted wheat, the yield reduction is due to shorter growth period and high temperature at crop maturity. Late-planted crop has lower germination, fewer tillers, smaller heads, shriveled grain and lower biomass than the timely planted crop. Therefore, the change in sowing time from present to two weeks earlier could result in addition of 2.0 million tones in national wheat production.
In rice-wheat area use of zero-tillage drill can help in timely planting. Similarly, relay cropping can be used in cotton-wheat zone in which cotton field is irrigated without cutting the cotton crop and then moist wheat seed is broadcasted. Bed sowing is another good option in cotton zone which results in early planting, water saving and better wheat crop stand.
In sugarcane zone government may ensure timely purchase of sugarcane from growers by sugar mills so that wheat could be planted in the area well in time and thus increasing the crop production. At present, due to delay of wheat planting in this zone, about 10-15% yield is reduced.
Crop breeders can also help by developing/evolving short duration rice and cotton varieties using modern breeding techniques so that wheat could get ample time to complete are normal life cycle leading to greater production.
TRENDS IN AREA AND PRODUCTION
Wheat production in Pakistan can be divided into three distinct periods: 1947-65, prior to the release of semi-dwarf wheats; 1966-76, the so-called “Green Revolution” period when High Yielding Varieties (HYVs) were rapidly adopted on about two thirds of total wheat area; and 1976 to date, post green revolution period when HYVs continued to spread to cover the major wheat area. A worth of Rs.220 billion wheat is produced in the country and one percent gain or loss in wheat production would be equivalent to rupees 2.20 billion. A bumper crop was harvested in 2006-07 because of suitable weather during the growing season, timely support price announcement, adequate supply of fertilizers, etc.).
DISEASE AND PEST PROBLEMS
Diseases, especially rusts (Stripe/Yellow Rust, Stem Rust, and Leaf Rust) and emerging scenario of increased incidences of Powdery Mildew and aphid are major biotic stresses of wheat crop that inflict heavy losses when in epidemic form. A simple one-year disease epidemic could cause a 2-3 billion-rupee loss to the country because of reduction in wheat yield (an example of 1977-78 epidemics). Therefore, breeders and pathologists should join hands to develop disease resistant and high yielding varieties in order to cope with threats created by ever changing rust races by using approaches like durable resistance.
FUTURE RESEARCH THRUSTS
• Breakdown of existing genetic resistance
• Site specific response of genotypes/technologies
• An increased incidence of different stresses
i) Biotic: (rusts, powdry mildew, nematodes, termites, rodents, aphids, BYDV)
ii) Abiotic: (drought, heat, salinity, cold)
• Quality wheat meeting the local and export standards/demands
– Gluten, Protein, Zinc
– Cadmium, KB, Striga
• More emphasis is needed on Resistance Breeding, Improved Quality, Disease Monitoring and Gene analysis.
PROVED VARIETIES FOR BARANI AND IRRIGATED AREAS
Key Reference : http://www.parc.gov.pk Resourse Person Dr. Yaqub Mujahid