Sixty Years Of Cotton Breeding In Cameroon: Interaction Between Genetic Improvement And Rainfed Cropping Conditions

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Author

ROMAIN LOISON

CIRAD – France

Abstract

Seed cotton (Gossypium  hirsutum L) yield in Northern Cameroon has been declining since the 80s despite breeding efforts. We used a set of widely grown cotton cultivars released at  different dates to study genetic improvement under different cropping conditions in Cameroon, and in controlled conditions. The genetic gain was estimated with a linear regression of the variety mean on its year of release (YR). Contrasts between genetic gains observed with different planting dates were estimated and tested. Our results revealed a genetic improvement on fiber yield of 3.3 kg ha-1 year-1 due to increased ginning out-turn. However, there was no genetic improvement on aerial biomass, harvest index or seed cotton yield. At the early stage of development, aerial and root biomass, and potential root extraction ratio of nutrients decreased with YR. So did leaf number and hairiness at the beginning of flowering. Carbon dioxide assimilation was not affected by YR. Neither were crop cycle duration and phyllochron. Although the potential of almost all fiber technological characteristics was improved under favorable water conditions, some (upper half mean length, short fiber index, uniformity index, and strength) were reduced in water-limited conditions. We concluded that cotton breeding efforts in Cameroon have successfully improved cotton fiber yield and the potential of most fiber technological characteristics. However, in water-limited conditions, fiber quality tended to decrease with the YR. There is still some room for seed cotton yield improvement.

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Ecophysiological analysis and modeling of genotype by environment by crop management interactions on cotton (gossypium hirsutum l.) in cameroon for the design of ideotypes

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Author

ROMAIN LOISON

CIRAD – France

Abstract

Cotton lint is the first natural fiber used in the world. Cotton provides income to more than 10 million people in West and Central Africa. In Cameroon, it is produced in rainfed conditions and water shortage is the major abiotic factor limiting yield and lint quality. In this context, a breeding program was initiated in 1950 to increase lint yield, fiber quality  and  disease resistance. After 60 years, this program has released more than 20 cultivars. However, seed cotton yield has been levelling off for more than thirty years. This study analyzed growth and development of main cultivars released from 1950 to-date to evaluate genetic gain including drought adaptation traits indirectly bred for. It also analyzed genotype by environment by crop management interactions (GEI) under water limited conditions in order to use a cotton simulation model in Cameroonian conditions. Then, crop simulation model was used to design cotton ideotypes under Cameroonian cropping conditions. An application of this work was in providing key drought adaptation traits to breed for cultivars that better withstand water stress. Firstly, phenotype evolution over breeding time and its interaction with cropping conditions in Cameroon was evaluated on cotton development, growth (including roots), yield, and fiber quality. Ten major cultivars were studied under rainfed conditions (field) and controlled conditions (greenhouse and phytotron). Classical GEI analysis of variance of cultivars and regression over their respective year of release were done. The results showed that the breeding program succeeded in improving cotton lint yield and the potential of fiber quality when the crop reached physiological maturity before the end of the rainy season. In  late  season drought, breeding reduced the fiber quality (fiber length, uniformity and strength). Most of the development and growth variables did not change with time, except the number  of leaves which  reduced.  Breeding  created cultivars with better potential fiber production and quality, but with reduced plasticity to sub-optimal environments and access to soil water. Secondly, an analysis of GEI for ecophysiological traits conferring a good response to drought was done in good and water limited conditions for a subset of four cultivars. The results indicated  that  water deficit  had  a  negative impact on almost all plant functions, both  under field and  controlled environments. The recent cultivar L484 bred for the driest production area had the fastest development, thickest leaves with most chlorophyll and thus maintained the highest level of photosynthesis and transpiration per unit of leaf area in water-limited conditions. In these conditions, L484 had the highest radiation use efficiency and water use efficiency maintenances. Despite these traits this cultivar did not show any improvement in terms of biomass, harvest index and cotton yield across water conditions. Cotton breeding program in Cameroon succeeded in providing a cultivar (L484) better adapted to local conditions, with a higher stability and faster development coupled with a strategy of growth maintenance, without any improvement in yield. Thirdly, the crop simulation model DSSAT CROPGRO-Cotton was used in order to design ideotypes with higher yield than existing cultivars. Field experiments in Cameroon were used to constitute the minimum dataset for the crop model calibration. Then, cultivars AC, L484 and forty-two virtual cultivars with ±20% from L484 parameter values were compared across 99 years of generated weather in two locations. Compared to L484, the cotton ideotypes in Cameroonian rainfed conditions had reduced emergence to anthesis duration, longer reproductive duration, higher level of photosynthesis maximum with thicker leaves, and smaller leaves for Far North region or bigger ones for North region.

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JCR-Physiology and Pathology Thematic Series Call For Paper

Coordinator:
Professor Hezhong DONG, Cotton Research Centre, Shandong Academy of Agricultural Sciences, China;
Professor Zhiguo ZHOU, Nanjing Agricultural University, China

Journal of Cotton Research is hosting a thematic series on cotton physiology and pathology. The research community is encouraged to share original findings, methodology, results, databases, and/or software and opinions.

Scopes that may be covered in the submissions may include, but are not limited to the following:

1. growth and organ development;
2. plant and shoot architecture;
3. water, fertilizer, light, etc. use efficiency;
4. intelligent agriculture;
5. rhizosphere and other plant-environment interactions;
6. main disease and resistance.

Submission Deadline: 30 September 2019

Submit Now

https://jcottonres.biomedcentral.com/cottonpap

Composting Cotton Mill Waste

ABSTRACT
Composting of cotton mill wastes may provide means for the production of a stable organic material, useful for soil improvement and as a substrate for plant growth. The aim of this work was to examine the composting process of cotton wastes and to evaluate the produced compost. Three composting piles were formed. In the first the ratio C/N was reduced to 28 with the addition of NH4NO3 , in the second cotton wastes were mixed with olive tree leaves at a ratio 2:1, respectively and in the third one a small amount of mature compost was added in order to trigger micro-organism activity. The results concerning the composting process, revealed that the reduction of the C/N ratio of the raw material is not a critical parameter for the composting of cotton mill wastes. The addition of olive tree leaves, as a bulking agent, enriched the final compost in nutrients and humic substances but delayed the overall process. The evolution of the composting process seems to be accelerated by the addition of a small amount of mature compost at the beginning. Decomposition of the materials lowered gradually the ratio C/N, due to carbon loss, reaching values between 9 and 10 while the nitrate content was increased significantly. The final produced composts were rich in nutrients and extractable humic substances. Tomato seedlings were superior in substrate with 30% (v/v) cotton mill wastes mature compost, compared to that in commercial substrates

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Cotton Pesticides in Perspective: Minimizing their Impact on Produce and in Riverine Ecosystems

ABSTRACT
Despite measures taken to reduce reliance on chemicals (e.g. Ingard cotton), production of Australian cotton still involves significant inputs of pesticides, with the potential to contaminate other agricultural produce and riverine ecosystems. Since 1993, the environmental fate and transport of pesticides used in cotton growing have been extensively monitored to minimize their impact as chemical residues. This research has focused on endosulfan as the major insecticide applied on cotton farms, and as a model for other chemicals. Positive results of the research that can help provide more sustainable practices are:

Information on field dissipation of endosulfan, in farm soils, surface water and on nearby pasture. In summary, dissipation of endosulfan from cotton fields occurred mainly by volatilization in the first 2-3 weeks after application; endosulfan isomers on cotton plants and in soils are quickly metabolized, with half-lives of 3-4 days. Two weeks after application, only 2-3 % of the amount applied in one spraying remained in the foliage. Unfortunately, there is some persistence of the metabolic oxidation product endosulfan sulphate in the field, with a ‘half-life’ in soil of about 100 days. However, by the start of the new growing season only 1-2% of the endosulfan applied remained on field as endosulfan sulphate, so there is little or no long-term accumulation.

A study of the degradation of endosulfan on pasture showed that residues fell to acceptable levels within about 3-4 weeks, dependent on the distance from the line of spray application. Runoff waters contain 1-2% of total endosulfan transported or dissipated off field in one season, major storms accounting for 50% of this amount; the relative significance of lateral rather than vertical leaching of soluble chemicals in grey-cracking soils (Vertisols) is emphasized.

Immunoassays (ELISA) provide rapid, inexpensive, field tests for pesticide residues, providing more comprehensive data-sets that allow decisions on the release of contaminated water and the assessment of the progress in remediation.

Field research protocols needed to generate data for registration purposes have been developed.

Significant progress towards safer use of pesticides in cotton growing, resulting from the preparation of a database indicating risk factors with specific pesticides and herbicides and a better understanding transport mechanisms. The adoption of better management practices that reduce these risks is already contributing to more sustainable cotton production.

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Beneficial Use of Municipal, Industrial and Agricultural Wastes in Cotton Production

ABSTRACT
Most row-cropped soils of the southern USA are low in organic matter and must be limed frequently to maintain an acceptable pH. Industry, municipalities and agriculture produce organic and other waste materials that can be used as soil amendments to increase both soil organic matter and pH. Field experiments were conducted on Gigger-Gilbert silt loam complex (fine-silty, mixed, thermic, typic fragiudalf-glossaqualf) to assess the effects of municipal biosolids, composted sewage sludge, paper mill sludge and paper mill boiler ash.

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