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THE COTTON RESEARCH INSTITUTE HAS BEEN THE NATIONAL CENTRE FOR COTTON RESEARCH SINCE 1925
Association and Location
Cotton Research Institute (CRI) is a government research institution that is situated 3 km west of Kadoma town along the Golden Valley (Chakari) road. The Institute falls under the Crops Research Division of the Department of Research and Specialist Services (DR & SS) in the Ministry of Agriculture, Mechanization and Irrigation Development.
Our Vision To become an internationally recognized centre of excellence for cotton research & technology development Our Mission To provide research-based technologies which promote viable and sustainable cotton production in Zimbabwe Our Mandate To develop and disseminate viable, practical, and sustainable cotton production technologies that meet the needs of the cotton industry in Zimbabwe. Our Core Values Teamwork, Professionalism, Creativity, Motivated Staff, Integrity, Accountability, Commitment, Transparency, Environmental Consciousness. Our Products
All cotton varieties currently grown in Zimbabwe were developed at CRI. Since 1980, CRI has released 18 cotton varieties. The revered history of Zimbabwe’s cotton industry that we are all proud of would not have been achieved without the technologies from the Institute.
Our varieties are an amalgam of expertise of Breeders, Agronomists, Entomologists, and Pathologists, all based at the Institute. RESEARCH PROGRAMMES In the last 30 years the research at CRI has focused on 4 main areas. These are Breeding, Agronomy, Entomology and Pathology as described below. BREEDING The main objective of the breeding section is to develop high yielding varieties of cotton which have lint characteristics suitable for the domestic and export markets. The section has three programmes that are categorized according to altitude.
b) Lowveld (
Breeding Trials
All varieties grown in Zimbabwe were developed, tested and released by Cotton Research Institute. Over the last 25 years, CRI released a total of 16 varieties. Seed cotton yields improved from 3-20% through use of varieties better adapted to low inputs and moisture stress. Fibre quality (length, strength, fineness) was improved through emphasis on higher quality medium staple Albar cotton varieties. Ginning percentage improved from 34-36% in pre 1980 cultivars to 43% in post 1980 cultivars (on a 40 saw gin). All these cultivars have resistance to bacterial blight disease. In areas where Verticillium wilt is a problem, the variety BC 853 can be grown as it has tolerance to the disease. All the varieties also have jassid resistance. Varieties with increased aphid tolerance have also been identified. These include SZ 9314 and FQ 902. Better pest control in some cultivars was achieved by breeding for a more open plant structure that allows for better spray penetration as is the case with recently released cultivars. In 2006 CRI released two cotton cultivars namely, CRI MS1 and CRI MS2. CRI MS1 is a medium staple cultivar which was offered to most dry and irrigated Middleveld (MSH) growers to complement the variety SZ 9314. It is a determinate variety with improved tolerance to Verticillium wilt and produces significantly more yield under irrigation. While its medium bolls may reduce hand picking productivity, the good seed cotton retention in open bolls and early maturing is beneficial to the grower. This variety has the best fibre quality in the medium staple range; combining good staple length and fibre strength. CRI MS2, is recommended for the south-east lowveld areas of the country (
Farmer Field Variety Demonstration
AGRONOMY
Agronomy Section Offices The agronomy section carries out research on improved crop management practices in order to increase cotton production and productivity. All aspects of cotton agronomy are studied and basic problems, for example, spacing, plant population, and nutrition are reviewed whenever new varieties are released. The section also does work on soil and moisture conservation and on irrigation. Weed management is a very important factor in cotton production and for this purpose, the screening of herbicides and studies on herbicide combinations are done. New fertilizers and growth regulators intended for use in cotton are evaluated and recommendations made on their application rates.
Research Workers Planting Agronomy Trials
The introduction of tied ridges and pot holing in the Middleveld and Lowveld increased the rate of water infiltration and reduced run off. This increased yields by up to 50%. Potash deficiencies often observed in cotton during the reproductive phase was corrected by increased potash content in super K fertilizer and deep placement of potash fertilizers to about 20 cm. This improved yields by 2-5%. This improvement in the fertilizer recommendations saw a general increase in fertilizer use by smallholder communal farmers consequently resulting in increased cotton production. The use of cattle manure in combination with fertilizer has also resulted in improved yields in the communal areas. While work on spacing and plant populations has enhanced pest and disease management, weed control, and ripping, and ultimately increased cotton yields. The section was responsible for testing and recommending local registration of the following herbicides for weed control in cotton; Codal gold 412.5 ec, Focus ultra, Fusilade Super, and fusillade forte. These have helped cotton farmers greatly in cutting down on the labour costs.
ENTOMOLOGY
The Entomology section develops and disseminates appropriate techniques for the control of insect and mite pests of cotton which individually or combined can result in serious yield losses. Red and Heliothis bollworms can cause yield losses of up to 60 percent. Aphids, red spider mites and soil pests can cause yield losses of up to 25, 40 and 100 percent respectively. The Pink bollworm can cause the cessation of cotton production once it invades cotton-growing areas. The major pests covered in the entomology programme are soil pests (termites and false wireworm), early sucking pests (aphids and jassids), late sucking pests (red spider mites, whiteflies and stainers) and bollworms (heliothis, red, pink and spiny).
The section examines pest/predator thresholds and scouting methods in all new varieties, screens new insecticides for low human and environmental hazards, examines spray application methods and equipment, evaluates varieties for pest resistance, looks at integrated pest management and other cultural methods for the control of pests.
Landmark achievements include:
The Closed Season The closed season for controlling pink bollworm refers to the period between 1 August and 5 October for cotton farmers in S.E Lowveld or 15 August and 20 October for cotton farmers in the remainder of the country when no cotton plant should be alive. Cotton plants are destroyed in order to create a “dead period” or “closed season” so as to minimize pest build-up, particularly that of the pink bollworm. This closed season is governed by the Plant Pests and Diseases Act [Chapter 19:08] which stipulates that any farmer who fails to comply will face either a fine or imprisonment, or both. The Acaricide Rotation Scheme The acaricide rotation scheme that was developed to prevent the build-up of red spider mite resistance divides the country into 3 regions and prescribes the chemical to be used for controlling red spider mite per region for 2 successive cropping seasons.
Below is a table and the map of Zimbabwe showing the regions showing the acaricide rotation to be observed for seasons 2009/10 to 2014/15.
Map of Zimbabwe showing regions for the Acaricide Rotation
The Pyrethroid Window Pyrethoids are broadspectrum chemicals that are used for controlling various cotton pests such as bollworms, strainers, jassids and leafeaters. The Pyrethroid Window was developed to prevent these pests developing resistance to these chemicals. It requires that the use of the Pyrethroids be confined to the periods shown in the table below.
Recent achievements include the use of seed dressing technology (Gaucho T 45 WS, Cruiser 35 FS) for the control of aphids, termites and false wireworm. As a result, farmers have improved plant stands resulting in high cotton production. The introduction of Mospilan 20 SP, an aphicide that requires two less sprays than Marshal 25 EC has also proved to be very cost effective against cotton aphids. Currently, acetamiprid is the most popular aphicide in Zimbabwe
PATHOLOGY
This work assesses germplasm coming out of the breeding programme for its tolerance to Bacterial Blight caused by Xathomonas campestris pv malvacearum before the variety can be released. The germplasm that comprises strains, lines and varieties is assessed for tolerance using the stem inoculation method. Scores of each line, strain or variety are taken 21 days after inoculation on a scale of 1-5. A score of 1-1.4 indicates the material is resistant; 1.5-2.4 indicates intermediate resistance and scores above 2.5 indicates susceptibility. All lines with a BB score of more than 3 are discarded from the breeding program.
Verticillium wilt is on the increase in Zimbabwe. This disease is very difficult to control once it is established in the field. There can be significant yield losses of 20 – 100% if susceptible varieties like SZ9314 are grown in a field with Verticillium wilt. In wilt-infested fields at Cotton Research Institute, and Henderson infection percentages are calculated at the end of the season. Most Zimbabwean cotton varieties have good tolerance to Verticillium wilt under natural infection.
The pathology section developed inoculation methodologies, screening techniques and also perfected storage of the bacterial blight pathogen. This has led to better screening of breeding materials for blight like FQ 902 and BC 853. The pathology section also developed and perfected inoculum preparation, screening techniques and the timing of stem inoculation for Verticillium wilt screening. This has helped in the selections for breeding materials used in crosses and in the release of cultivars with Verticillum wilt tolerance like BC 853 and CY 889. The section also established that Alternaria leaf spot is a problem if the crop is predisposed to stress conditions e.g. potassium deficiencies. Amelioration of potassium deficiencies reduced disease incidence. This section developed cost effective inoculum preparation and storage techniques for Rhizoctonia solani which helps in effective screening of fungicides against the pathogen. Effective fungicides for seed dressing and in-furrow treatments were recommended to farmers. The section recommended Maxim XL fungicide for seed treatment to prevent seedling diseases. Fungicides reduce seedling diseases and extended cotton production to areas not possible before because of stand losses caused by seedling diseases.
CURRENT COMMERCIAL VARIETIES IN ZIMBABWE
The varieties CRI-MS-1 and CRI-MS-2 were released in 2006. These varieties are significantly superior to SZ 9314 in both yield and environmental resilience and are now a new benchmark for CRI’s variety development program. DR&SS hopes that these varieties will be available to growers soonest as further delays will prejudice the whole cotton industry. CRI is committed to continuous improvement in cotton variety development, production technologies development, evaluation of agro-chemicals used in cotton, and information dissemination.
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