Irrigation’s effect and applied selection on the fiber quality of Ethyl MethaneSulfonate (EMS) treated upland cotton (Gossypium hirsutum L.)

[Background] Producing rainfed cotton (Gossypium hirsutum L.) with high fiber quality has been challenging in the Texas High Plains because of extended periods of insufficient rainfall during sensitive boll developmental stages. Genetic variation created by Ethyl MethaneSulfonate (EMS) mutagen has successfully improved fiber quality of cotton. However, little is known about the effect of water deficit environments on fiber quality. Three EMS treated populations were advanced from the first to the fourth generation (M1 to M4) as bulk harvested populations. In 2014, single-plant divergent selection was applied based on perceived morphological and agronomic differences seen during and at the end of the season.

[Results] Analyses from these selections in 2014–2016 showed significant (P < 0.05) improvement between and within populations for fiber traits (micronaire, length, strength, uniformity, and elongation) when compared with the original non-treated EMS source; some selections were found to have excellent fiber quality under diverse irrigation-regimes.

[Conclusions] Some of these selections are being considered for germplasm release and could be useful for improving the fiber quality of cotton under water limited conditions, thereby helping to ensure the long-term survival of the cotton industry on the Texas High Plains.

Irrigation’s effect and applied selection on the fiber quality of Ethyl MethaneSulfonate (EMS) treated upland cotton (Gossypium hirsutum L.)
WITT Travis W. , ULLOA Mauricio, PELLETIER Mathew G. , MENDU Venugopal and RITCHIE Glen L.
Journal of Cotton Research. 2018; 1:17.
https://jcottonres.biomedcentral.com/articles/10.1186/s42397-018-0016-8

Selection Efficiency for Cotton Fiber Quality in Segregating Material by Different Instruments

ABSTRACT
A breeding programme to develop varieties with a wide range of quality parameters to meet various end uses, requires rapid and accurate fiber quality assessment. This paper examines the potential of instruments to provide data for the selection of fiber quality parameters. Segregating genetic material (F2) from five intra-specific crosses was tested for fiber length, fineness, maturity and strength with the Fibrograph, Pressley, Fibronaire, High Volume Instrument (HVI) and Advanced Fiber Information System (AFIS). The variability of the coefficient of variation (CV) served as the criterion for testing the reproducibility and the accuracy of the measurements. The results proved that for length parameters the Fibrograph and for strength the Pressley tester were the most appropriate. The AFIS gave better estimations of fineness and maturity. The use of laboratory instruments for most of the fiber properties is suggested on the basis of these results. Nevertheless the choice may depend on other parameters such as the range of characters measured and cost effectiveness.

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Changes in Breeding Strategy for Needs in a Liberalized Cotton Industry

ABSTRACT
Commercial cotton (G. hirsutum L.) production has been based on BPA and SATU varieties, grown in two ecological zones. Both have had a strong world market, the stronger, longer and finer fiber BPA finding a different market niche. The collapse of the seed replacement system developed by the Department of Agriculture and liberalization of the cotton industry has resulted in problems of variety deterioration and mixing, leading to non-uniform and poor quality lint. These new challenges necessitated changes in breeding objectives and strategy. In 1993 breeding work was revived at SAARI with the strategy of developing a variety with good adaptation in the two zones for high yield, resistance to pests and high lint quality. Selections were made from existing and purified BPA and SATU stocks, and progenies arising from intra- and inter-variety crosses. Variety checks and advanced lines of 9 SATU and 11 BPA stocks were compared, using single and combined analysis of variance over 8 locations and 3 years, ordination and cluster analyses. At a three-group level, one group membership was consistent over the three seasons. The members expressed similar response patterns and good yield and constituted the elite entries. G x E interactions were not significant for yield but fiber characteristics of BPA entries were influenced by the environments. SATU and BPA lines performance was comparable except at locations of very low environmental index where SATU was better. Pattern analysis results indicate that the higher quality BPA which is also more bacterial blight resistant, can be grown in a wider range of environments than previously anticipated.

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Chromosomal Location of RFLP Markers Linked to QTL in Cotton

ABSTRACT
Plant breeders are primarily involved in improving complex quantitative traits (QTL) that are controlled by many genes. Molecular markers linked to QTL will help breeders to monitor the hereditary materials associated with the QTL. Recently, our research unit reported a linkage map of a class of molecular markers called Restriction Fragment Length Polymorphism (RFLP) and QTL using a second-generation (F2) population of improved upland cotton cultivars. The objective of this paper is to identify the chromosomal location of some of the RFLP and QTL linkage map that our unit reported.

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Combining Ability for Fiber Properties in Influential Upland Cotton Varieties

ABSTRACT
A great number of germplasm lines have been used as parents in cotton improvement. Those contributing a larger proportion of genes to modern cotton cultivars than other germplasm are called influential lines. Based on the pedigree analysis of 260 cotton cultivars released in the United States between 1970-1990, the most influential cotton varieties from 16 cotton breeding programs were identified. The objective of this study was to investigate the general and specific combining ability (GCA and SCA, respectively) for fiber properties among the most influential lines from 10 Upland cotton breeding programs. A half diallel crossing scheme with the parents and 45 F1’s was grown in replicated trials at two locations in 1997. Fiber properties measured by HVI included micronaire, strength, length, uniformity and elongation. The significance of GCA and SCA effects detected and how they can be used to develop varieties with improved fiber characteristics is discussed.

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Reaction of some Segregating Populations and Newly Introduced Cotton

ABSTRACT
Resistance of cotton cultivars in the Sudan to Xanthomonas campestris pv. malvacearum conferred by B2 B6 gene combination is no longer effective after the appearance of new races of the pathogen. Thus, new sources of resistance or new gene combinations are needed to protect the crop. This study was carried out to identify such a new source or gene combination to confer resistance to the prevailing races in the Sudan. Highly resistant plants from some F2 plants were recovered. The S295 cotton cultivar (B12) showed high resistance to post-Barakat race. Some MAR cotton germplasm (MAR 5 & 6) was also showed high resistance to this race. This high resistance was also observed in the F4 segregating populations of the introduced crosses E1043 × B2 B6 and B2 B6 × Pima 32.

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Participatory Cotton Breeding in Benin

ABSTRACT
A cotton improvement programme based on participatory plant breeding methods employed for food crops has been implemented in Benin for ht e last two years. It aims at reinforcing the relationship between farmers and research, regionalising cotton breeding thanks to active collaboration with grower associations. Hopefully, farmers will also develop skills in seed production. First results confirm the variability in a breeding population created in 1996 by intercrossing fourteen genotypes, representing a wide range of variability. The interest shown by breeder-farmers looks intact with willingness to continue with this partnership. In order to ensure that it will endure, contracts with farmers are being considered.

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Achieving Multiple Pest Tolerance Through Manipulation of Morphological Features in Cotton

ABSTRACT
Breeding for tolerance to sucking pests and bollworm in cotton is treated as mutually exclusive events. Selection for resistance to sucking pests with more hairy leaves brought increased susceptibility to bollworms. An effort was made to select genotypes with high density hair on the lower leaf surface and low density hair on the upper surface. The number of hairs on both the upper and lower surfaces of the leaf blade and midribs and glands on the calyx were recorded. The yield was also assessed. The material used represented collections from India, the USA, China and the Central Asian Republics. Generally lower numbers of hairs on the midribs and leaf blade with more glands on the calyx and less bracteole teeth were recorded on bollworm tolerant genotypes. The bollworm tolerant lines exhibited higher yields than susceptible lines under unprotected conditions. Few of these lines showed differences in hair density on the upper and lower leaf surfaces. When the lower leaf surface had 70% more hair than the upper surface, the line had a jassid grade II. Only indigenous lines exhibited bollworm tolerance. Use of multiple tolerant genotypes in transgenic cotton studies opens new dimensions in pest tolerance breeding in cotton

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Inheritance Studies of Quantitative Characters in Upland Cotton

ABSTRACT
Before any efficient breeding methodology can be developed it is necessary to analyze the genetic architecture of quantitatively inherited characters like yield and its components. Understanding the nature of gene action involved in the expression of a character is helpful in deciding the breeding procedure to be used for improvement of that character. Genetic analysis was performed through sequential model fitting to analyze the variation among generations derived from a cross of two diverse parents, MU-2 and Rs-453, for seed cotton yield per plant, number of bolls per plant, boll weight, ginning out turn and lint index. The analysis indicated the presence of both additive and non-additive genetic effect. Epistasis was found to be important in controlling the genetic effect for most characters. The magnitude of non-additive genetic component was found to be significant for number of bolls per plant, ginning outturn and lint index. Performing bi-parental mating in early segregating populations would facilitate simultaneous exploitation of additive and non-additive gene effects to achieve improvement in the characters

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Colour cotton research in Mahyco, India

ABSTRACT
The work on develop naturally coloured cotton commenced at Maharashtra Hybrid Seeds Co. Ltd. (Mahyco, Jalna, India) in 1993. The objectives were the identification of coloured linted cotton hybrids with high yield and superior fiber traits. Colour cotton was grown and used by mankind as long ago as 2500 BC. Damaging effects of synthetic dyes on the ecosystem has led to expanded interest in naturally coloured cotton. Environment conscious communities in developed countries, particularly in Europe and USA are now developing cotton textiles free from harmful dyes and pesticide residues (Anon 1995). “Fox” Fibers coloured cotton have caught the attention of scientists and textile processors; hence the new interest in India. In the study, heterosis for yield and fiber characters of 40 intra-hirsutum hybrid combinations, obtained from crossing colour linted strains as male and elite white linted cultivars as female was evaluated found that the selected hybrid combinations had better fiber properties than the coloured cotton parents. The results indicate that of all the combinations evaluated, the hybrid MBCH-9 with a potential yield of 1800-2000 kg seed cotton per hectare, upper half mean length of 27 – 28 mm, Micronaire of 3.9 – 4.2, fiber strength at 1/8 gauge of 24 – 25 gm/tex, uniformity index of 78 – 80 and light shining brown colour appeared most promising. Improvement in agronomic and technological performance in evolution of colour cotton hybrid will be required for commercial cultivation and the textile industries.

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