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[Background] Cotton is an important fiber crop worldwide. The yield potential of current genotypes of cotton can be exploited through hybridization. However, to develop superior hybrids with high yield and fiber quality traits, information of genetic control of traits is prerequisite. Therefore, genetic analysis plays pivotal role in plant breeding.
[Results] In present study, North Carolina II mating design was used to cross 5 female parents with 6 male parents to produce 30 intraspecific F1 cotton hybrids. All plant materials were tested in three different ecological regions of China during the year of 2016–2017. Additive-dominance-environment (ADE) genetic model was used to estimate the genetic effects and genotypic and phenotypic correlation of yield and fiber quality traits. Results showed that yield traits except lint percentage were mainly controlled by genetic and environment interaction effects, whereas lint percentage and fiber quality traits were determined by main genetic effects. Moreover, dominant and additive-environment interaction effects had more influence on yield traits, whereas additive and dominance-environment interaction effects were found to be predominant for fiber traits. Broad-sense and its interaction heritability were significant for all yield and most of fiber quality traits. Narrow-sense and its interaction heritability were non-significant for boll number and seed cotton yield. Correlation analysis indicated that seed cotton yield had significant positive correlation with other yield attributes and non-significant with fiber quality traits. All fiber quality traits had significant positive correlation with each other except micronaire.
[Conclusions] Results of current study provide important information about genetic control of yield and fiber quality traits. Further, this study identified that parental lines, e.g., SJ48–1, ZB-1, 851–2, and DT-8 can be utilized to improve yield and fiber quality traits in cotton.
[Title] Genetic analysis of yield and fiber quality traits in upland cotton (Gossypium hirsutum L.) cultivated in different ecological regions of China
[Authors] SHAHZAD Kashif+, LI Xue+, QI Tingxiang, GUO Liping, TANG Huini, ZHANG Xuexian, WANG Hailin, ZHANG Meng, ZHANG Bingbing, QIAO Xiuqin, XING Chaozhu* & WU Jianyong*
Journal of Cotton Research. 2019, 2: 14
[Background] Climate change and particularly global warming has emerged as an alarming threat to the crop productivity of field crops and exerted drastic effects on the cropping patterns. Production of cotton has been dropped down to one million bales from 1.4 million bales since 2015 in Pakistan due to the increase in temperature at critical growth stages, i.e., flowering and boll formation. Keeping in view the importance of cotton in the country, this study was conducted to investigate the genetic effects conferring heat tolerance in six populations (P1, P2, F1, F2, BC1 and BC2) developed from cross-1 and cross-2, i.e., VH-282 × FH-142 and DNH-40 × VH-259.
[Results] The results revealed that cross-1 performed better in heat stress as compared with cross-2 for majority of the traits recorded. Boll weight and ginning outturn (GOT) were highly effected under heat stress and had negative correlation with Relative cell injury (RCI). Boll weight, fiber length, fiber strength and fiber fineness were under the control of non-additive gene action, whereas RCI was controlled by additive gene effects. Lower values of genetic advance coupled with higher values of broad sense heritability for these traits except RCI confirmed the role of non-additive genetic effects. Duplicate types of epistasis were recorded for fiber strength in cross-1 in normal condition. However, complementary type of non-allelic interaction was recorded for fiber strength under normal condition, fiber fineness and RCI under heat stressed condition in cross-1. Likewise, boll weight, GOT and fiber length in populations derived from cross-2 in normal condition were also under the influence of complementary type of non-allelic interaction. Significant differences among values of mid parent and better parent heterosis for boll weight in both normal and heat stress condition provided the opportunity to cotton breeders for utilization of this germplasm for improvement of this trait through exploitation of heterosis breeding.
[Conclusion] Cross-1 performed better in heat stress and could be utilized for development of heat tolerant cultivar. RCI was under the influence of additive gene action, so one can rely on this trait for screening of large number of accessions of cotton for heat stress. While other traits were predominantly controlled by non-additive gene action and selection based on these should be delayed in later generations.
[Authors] SALMAN Muhammad, ZIA Zia Ullah, RANA Iqrar Ahmad, MAQSOOD Rana Haroon, AHMAD Saghir, BAKHSH Ali, AZHAR Muhammad Tehseen
Journal of Cotton Research. 2019; 2: 9
Rahman, Mehboob-ur-1; Ali, Ahmed1; Qaiser khan, Ali1; Abbas, Ammad1; Rahmat, Zainab1; Sarfraz, Zareen1; Khalid, Anum1; Gul, Maryam1; Munir, Atif1; Atifiqbal, Muhammad1; Scheffler, Jodi2; Scheffler, Brain2;
1National Institute for Biotechnology & Genetic Engineering (NIBGE) Faisalabad, Pakistan. 2Jamie Whitten Delta States Research Center, Stoneville, Mississippi, USA
Cotton leaf curl, a disease of viral origin, is transmitted by a whitefly (Bemisiatabaci), was first reported in 1912 in Nigeria, and later spread to Egypt, Sudan, India and Pakistan, and recently in China. The disease has significantly challenged the sustainability of cotton production in Pakistan with annual yield penalty of two million bales. Efforts were made in developing resistant cotton varieties, which upheld the resistance for couple of years but overcame by the evolution of new strain of the virus (now called as cotton leaf curl Burewala virus). For protecting the most important natural fiber producing crop, a mega project aiming at the improvement of genetics of the cotton plant for combating the disease, was initiated in 2011 under Pak-US (managed through ICARDA, Pakistan) joint venture program. Till now, more than 3500 cotton accessions have been screened; and 33 accessions were found asymptomatic while G. hirsutum 2472-3 and G. hirsutum 3661 showed high tolerance to the disease. Among the asymptomatic, G. hirsutum Mac-07 (photoperiod insensitive) is being used extensively by multiple cotton research institutes for developing resistant cotton cultivars. A number of mapping populations by involving tolerant and resistant cotton genotypes with the mostsusceptible cotton species were developed. For example, mapping populations were developed by crossingG. hirsutum 2472-3 (tolerant), G. hirsutum Mac-07 (resistant) and highly sensitive genotypes G. barbadense PGMB-66, G. barbadense PIMA S7, respectively. A total of 1200 SSRs were surveyed on parent genotypes of G. hirsutum 2472-3 and G. barbadense PGMB-66 (Cross-I). Out of these, 113 were found polymorphic. These were surveyed on F2population. In second population (derived from a cross G. hir 2472-3/G. bar PIMA S-7, Cross-II), we surveyed 170 SSRs. Out of these, 24 polymorphic were surveyed on F2population. Similarly, we too surveyed 435 SSRs on the parent genotypes of third mapping population (Mac-7/PIMA S-7, Cross-III). A total of 18 polymorphic primers were surveyed on F2 population. Based on our limited studies, we were able to identify two QTLs i.e. QCLCuD25 and QCLCuD26 from Cross-I population study, six QTLs i.e. QCLCuD3, QCLCuD4, QCLCuD7, QCLCuD8, QCLCuD9, QCLCuD14 from Cross-II population study, and three QTLs from cross-III population. These studies will pave the way for not only initiating marker-assisted breeding for the development of resistant cotton cultivars in Pakistan but will also provide a comprehensive information to the international cotton community for combating the disease.
Department of Plant Breeding and Genetics
Punjab Agricultural University, Ludhiana – 141004, Punjab, India
Heterosis breeding has played rich dividends in crop plants including cotton and is a sure way of increasing crop production and productivity in a shorter time span. In India, all the four cultivated species of cotton and their interspecific (G. hirsutum x G. barbadense; G. arboreum x G. herbaceum) hybrids are grown. In fact, India has been a leader in the production and commercialization of cotton hybrids. Earlier, hand emasculation and pollination was used for the production of hybrid seeds in G. arboreum in India. LDH 11 (1994) was the first commercial intra-arboreum hybrid in the entire North Indian cotton growing states. However, manual emasculation of the floral buds makes hybrid seed production more labour intensive. Availability of genetic male sterile (GMS) lines such as DS-5, GAK 423 has resulted in the development and commercialization of several desi cotton hybrids. Some of the intra-arboreum hybrids released for commercial cultivation in different North Zone states using DS 5 as the female parent include AAH 1, Moti (LMDH 8), Raj DH 9, CICR 2, PAU 626H, and FMDH 9. There are certain limitations nuclear male sterility system. For example, no marker linked to male sterility trait is available at the seedling state in DS 5 and male sterile/fertile plants have to be identified at the flowering stage only. As in a GMS line male fertile and sterile plants are observed in a frequency of about 1:1, and fertile plants have to be removed, about half of the plants in a GMS line are available for hybrid seed production, that increases the cost of the hybrid seed. Though, genetic control of male sterility in DS-5 is simple (monogenic), yet the transfer of this trait/gene in different lines is very time consuming due to its recessive nature. Efforts to map the gene conditioning male sterility in DS 5 with molecular markers are going on in our Department. Mapping of this gene will facilitate its precise transfer across the genotypes and identification of male sterile plants at the seedling stage.
I.S. Katageri, *Rashmi Ranjan Toppo, and B.M. Khadi
*Department of Biotechnology, College of Agriculture University of Agricultural Sciences, Dharwad – 580 005, India
Cotton is one among the few often cross-pollinated crops, where the achievement of commercial exploitation of heterosis is comparable to even that of cross-pollinated crops like maize. The main bottleneck in exploitation of hybrid vigour in cotton is the complicated technique of seed production, which involves hand emasculation and pollination that makes hybrid cotton seed more costly. To improve the remunerative value of hybrid seed production and commercial cultivation of hybrid it is necessary to develop productive male sterile based hybrids. Although Cytoplasmic Genetic Male Sterility is available, the identification of restorer for 100 percent fertility restoration was problematic. Molecular markers are coming handy in identifying such plants. The present study, therefore, comprised 413 individual plants comprising of 164 A-line and B-line, 124 IPS of R-line, 13 hybrids, 3 cultivars, 4 wild species, 24 G. hirsutum germplasm lines, 80 RILs and 1 GMS line were studied during 2012-13 and 2013-14 at ARS, Dharwad farm. Twenty four molecular markers known to be associated with fertility restoration (10 RAPD, 7 SSR, 6 STS, and 1 TRAP) were studied. Out of these, 3 STS markers (Y1107, UBC 147 and UBC 607) were able to amplify only in 44 plants out of 124 belong to DR-7 (known for fertility restoration). No amplification was observed in diverse genetic background of A-lines and their respective B-lines, wild species, G. barbadense var. SBYF 425, G. arboreum var. DLSa 17, G. herbaceum var. Jayadhar, G. hirsutum germplasm lines and Abadhita GMS line (sterile and its maintainer line). However amplification by these three markers was recorded in 6 out of 80 RILs of DCH-32 hybrids. Co-segregation for 98-100 percent fertility restoration and molecular markers associated was observed in F2 of cross between A line and fertility restorer carrying three molecular markers.
Kahramanmaras Sutcu Imam University, Faculty of Agriculture, Field Crops Department
The aim of this project carried out in 2011-2013 under Kahramanmaras conditions was to develop superior lines for seed cotton yield, ginning outturn and fiber technological properties from four naturally coloured cotton populations (Gossypium hirsutum L.) crossing naturally and having genetic variation using method of pedigree selection. Naturally coloured cotton populations used as materials had fibers coloured light brown, dark brown, green and creamy.
In 2011 year, 100 individual plants were selected from each coloured population according to field observations such as fiber colour, plant form, boll and leaf form, plant height, number of monopodia, number of sympodia, boll number per plant (for four colour 4×100=400 plants). Each plant was harvested separately. In 100 plants (for each colour) seed cotton yield, ginning outturn, 100 seed weight, boll weight, seed cotton weight per boll, fiber length, fiber fineness, fiber strength, fiber elongation, fiber uniformity, short fiber index, trash area, trash count, trash degree were recorded. According to seed cotton yield, ginning outturn, 100 seed weight, boll and ﬁber traits 50 individual plants were selected to be sown in next year. In 2012 year, self pollinated seeds of 50 plants selected from four populations having diﬀerent ﬁber colours were sown in the separate rows 5 m in length. Thus, 200 progeny rows were formed in total (50 dark brown, 50 light brown, 50 green, 50 creamy). The all plants in rows were self pollinated during flowering period. Individual plant selection were repeated in progeny rows according to ﬁeld observations. 2 or 3 plants selected according to ﬁeld observations in each row were harvested separately (For each colour 50×2=100 plants, in total 100×4=400 plants). For each colour in 100 plants seed cotton yield, ginning outturn, 100 seed weight, boll and ﬁber traits were recorded. According to these traits 50 individual plants were selected. Self pollinated seeds of these plants were sown in the next year. In 2013 year these steps were replicated.
As a result, in each colour individual plants higher yielding and having higher lint properties were obtained. Second part of this project continuous to obtain homozygous and pure lines using self pollination from 2014 to 2016.
Ahmed M. Mustafa, Maria Abdalla Abdelrahman Musa and Abdrahman Abdellatif
Agricultural Research Corporation, Wad Medani, Sudan
New Extra-fine cotton (Gossypium barbadense L.) lines have been developed with intermediate reaction to bacterial blight disease. The advantage seed cotton yield of the lines over Barakat 90 was in the range of 4-28 per cent. They had longer, stronger and ﬁner ﬁbers compared to Barakat-90. The lines were earlier cropping and gave 45.6-61.2 per cent of their yield in the ﬁrst pick compared to 43.5 for Barakat-Hence these lines signify improvement in seed cotton yield, ﬁber quality, earliness of maturity and reaction to bacterial blight in Sudan extra-fine cotton.
Suresh handi and I.S.Katageri*
*Professor and Head,
Institute of Agribiotechnology, University of Agricultural Sciences, Dharwad, Karnataka, INDIA, firstname.lastname@example.org
Determination of the genetic basis of complex quantitative traits has been one of the major scientific challenges in the process of crop improvement. To assist in this effort, an increasing number of genomic and genetic resources are today exploitable, including genome sequences, germplasm collections and public databases of genomic information. The availability of these resources, the recent advances in high-throughput genomic platforms and the increasing interest in exploring natural genetic diversity, make association mapping an appealing and affordable approach to identify genes responsible for quantitative variation of complex traits. Association mapping requires high-density oligonucleotide arrays to efficiently identify SNPs distributed across the genome at a density that accurately reflects genome wide LD structure and haplotype diversity. For Cotton, a high-density infinium array (63K SNP array) was recently built (Hulse-Kemp et al., 2015), with 63058 SNPs developed from different species which resulted in suitability for genome wide association analysis.
Association or linkage disequilibrium (LD) mapping revolutionized genetic mapping in humans, and is increasingly used to examine in plant genetics; it is an efficient way of determining the genetic basis of complex traits. In the present study, association mapping was examined with the use 201 germplasm of G. hirsutum lines evaluated for yield, yield components and fiber quality traits. Results from fastSTRCUTURE identified 12 subgroups in the population. The critical value of R2 was set to 0.243 was taken as a threshold to claim LD between two loci. About 3.13 % marker pairs showed significant high LD (R2=1) and about 82.72 percent pairs of loci were in linkage equilibrium with R2 values less than 0.3. Mixed linear model accounting for population structure and kinship has identified 349 significant marker trait associations for yield, yield components and fiber quality traits effectively controlling false positives reported in GLM (642 markers). More number of markers showing significant association were situated on D genome indicates than ‘A’ genome indicates detection of diverse SNP markers than ‘D’ genome or this may also because of the dense marker coverage in the D genome. The phenotypic variation explained by makers in this study was smaller suggesting minor QTLs or polygenic nature of these traits.
CIRAD – France
Crop simulation models (CSM) dynamically estimate agricultural production as a function of weather and soil conditions, and crop management. They can be used for evaluating cultivars in actual and future tropical conditions. In Northern Cameroon, cotton (Gossypiumhirsutum L.) is grown exclusively in rainfed conditions and its yield has been decreasing steadily since the 80s. Therefore our objectives were to evaluate the usefulness of CSM to identify current rainfed cotton ideotypes for two contrasted environments of northern Cameroon. Based on field observations constituting the minimum dataset, phenology, morphology, leaf area index and yield simulated by CROPGRO-Cotton were successfully calibrated and validated in our conditions. Results showed that ideotype should have earlier anthesis date, longer reproductive duration, thicker leaves with higher potential assimilation rate compare to the reference cultivar (L484). In the North region, it seemed that having bigger leaf than L484 should be favorable whereas in the Far North smaller ones are more suitable to local drought-prone conditions. We concluded that morpho-physiological traits could and should be imported into breeding programs in F5 generation where high genetic diversity still exist and plant material start to be considered as a line rather than a single plant. Consequently, we invite breeders to target cultivars with low “emergence to anthesis” to reproductive ratio, thick leaf, high chlorophyll content, and smaller leaf for the conditions with the lowest water availability and bigger ones for the conditions with best water availability.