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In recent past, dyeing in textile industry have attained massive growth, resulting in environmental pollution. It necessitates the need for the resurrection of research interest in naturally coloured cotton. In this view, the present study was conducted in two F2 populations derived by crossing naturally brown coloured cotton Red 5-7 and white linted cotton MCU 5 and its reciprocal at the Department of Cotton, Tamil Nadu Agricultural University during kharif, 2019. The phenotypic variance was higher than the genotypic variance for all traits and the magnitude of difference between PCV and GCV for five fibre quality traits was less which pointed out less environmental influence. Heritability and GAM were high for yield-related traits, such as the number of bolls per plant and seed cotton yield/plant, making them suitable targets for selection. Association studies revealed that the number of bolls/plant and boll weight were positively correlated with the seed cotton yield/plant with positive direct effect. Thus, direct selection of these traits will assist in the yield improvement programme in coloured cotton. [ABSTRACT FROM AUTHOR]

Gene effects for six quantitative and two quality traits were estimated from two upland cotton crosses through generation mean analysis from 6 generations (P1, P2, F1, F2, BC1 and BC2 ). Results revealed that the dominant gene action was observed in the majority of the traits. The traits, plant height, number of sympodial branches per plant, number of bolls per plant, seed cotton yield per plant, ginning percentage and micronaire value possessed opposite signs of [h] and [l] indicating the role of duplicate gene action controlling the traits which will pose a hindrance to a plant breeder while attempting selection in long run. Therefore, heterosis breeding would be advantageous and none of the studied traits were found to be controlled by the complementary type of interaction. Epistatic gene interactions also showed a significant role in the inheritance of all characters in one or another cross. Both additive and dominant genetic interactions with inter-allelic interactions should be taken into account for varietal improvement, which is the main breeding objective. Reciprocal recurrent bi-parental mating methods would break the undesirable effects. [ABSTRACT FROM AUTHOR]

An investigation was carried out to understand the gene action for seed oil, seed protein, seed gossypol, seed cotton yield and fiber density through intra-hirsutum crosses. Combining ability and gene action were studied in eighteen hybrids involving six elite varieties as lines (females) and three fuzzless G. hirsutum accessions as testers (males) in Line x Tester analysis. This study revealed the preponderance of non-additive gene action on all the traits studied including seed cotton yield. The elite general combiners identified were CO14 for seed oil and seed protein and CO17 and AKH98-81 for fiber per seed and fiber density. The best specific combiner was SVPR4 x AKH98-81 for seed oil, fiber density and seed cotton yield. A correlation study revealed a strong positive association of seed oil content, lint index, micronaire value, fiber per seed and seed fiber density traits with seed cotton yield. This study indicated the possibility of developing high-yielding hybrids with high seed oil, seed protein content and better fiber quality traits through heterosis breeding. [ABSTRACT FROM AUTHOR]

Background: Gossypium hirsutum, the most widely cultivated crop in the world has concurrent importance for both fibre quality and yield. Polygenes regulate cotton output and a variety of factors affect the characteristic. As a result, it is essential to have thorough knowledge of the relationships between different component traits and fibre quality. Thus, the aim of the study was framed to know about the correlation along with cause-and-effect relationship among the economic traits. Mathods: Eight parents and 56 hybrids made up the experimental sample for our study, which were evaluated for 18 economically significant traits. The study was conducted at Department of Cotton, Tamil Nadu Agricultural University, Coimbatore, in 2021-2022. Result: Analysis of variance was highly significant for all the traits studied. The result of correlation revealed that the traits viz., number of bolls per plant, boll weight, number of seeds per boll, upper half mean length and fibre strength had a high magnitude of positive correlation with seed cotton yield at both genotypic and phenotypic levels. Path analysis represented the direct effects of upper half mean length, uniformity index, number of bolls per plant, number of seeds per boll and fibre strength on seed cotton yield. Hence, these traits can be used as selection criteria for yield improvement in cotton. [ABSTRACT FROM AUTHOR]

One hundred upland cotton germplasm accessions were evaluated for eight traits to evaluate the per se performance, genetic variability, heritability, genetic advance as a per cent of mean, correlation and path analysis. The estimation of variability indicated that the number of monopodia per plant had high GCV and PCV. High heritability along with high GAM was found in plant height, internode length, the number of monopodia per plant, the number of sympodia per plant, the number of bolls per plant and seed cotton yield per plant which suggested that additive gene activity had a significant influence in the inheritance of these traits. Correlation analysis showed that the number of sympodia per plant, the number of bolls per plant and boll weight have a significant high positive correlation on the seed cotton yield. Path analysis showed that the number of bolls per plant and boll weight had the highest positive direct effect on seed cotton yield per plant. [ABSTRACT FROM AUTHOR]

The present study was investigated in thirty five hybrids of Gossypium hirsutum L. for combining ability and heterosis for ten yield and fibre contributing traits. These hybrids were obtained by the crosses made between seven lines and five testers. None of the crosses was superior for all the traits studied for the mean performance. The hybrid TCH 1199 × GTHV 323 showed the highest mid and better parent heterosis for the lint index and the hybrid TCH 1828 × RHC 1409 exhibited the highest significant mid and better parent heterosis for ginning outturn. The characters viz., boll weight and single cotton yield per plant were identified to have the highest significant mid and better parent values in the hybrid BSH 18 × RHC 1409. For yield contributing traits viz., the number of sympodial branches per plant and the number of bolls per plant out numbered in the hybrid CO 14 × KC 3 with the maximum standard heterosis among the thirty five hybrids. Combining ability analysis exhibits the dominance of non- additive gene action in all yield and fibre quality contributing traits. Among the lines CO 14 and TCH 1828 were estimated as the best combiners for yield and quality traits, respectively. Among the testers, KC 2 and KC 3 were found to be the best among all the five testers. The hybrid BSH 18× RHC 1409 exhibited the highest sca for the boll weight and seed cotton yield per plant and the hybrid BSH 18 × GISV 323 exhibited the highest sca for the quality traits viz., ginning out turn and upper half mean length; TCH 1828 × KC 3 and CO 14 × KC 2 best performed hybrids for sca values for the quality traits viz., elongation length and micronaire values. [ABSTRACT FROM AUTHOR]

Successful hybrid development work in cotton involves unearthing information of combining ability, heterosis and per se performance of the genetic material. This study involved multi‐environment estimation of combining ability and heterosis along with the stability of per se performance using Bt cotton genetic materials for seed cotton (Gossypium hirsutum L.) yield. Combining ability analysis across environments showed significant effects on the performance of genotypes, general combining ability (gca), specific combining ability (sca), genotype × environment, GCA × environment, and SCA × environment interactions. Combining ability variance revealed the predominance of nonadditive gene actions for seed cotton yield. The mean performance combining ability estimates were varied with the locations for parents as well as for hybrids. In a low yielding environment, the transgenic BGI parents, as well as hybrids, showed superior seed cotton yield levels compared with BGII or non‐Bt versions. There was a significant increase in heterosis noticed in BGII hybrids compared with BGI hybrids in a low yielding environment. The stability parameters showed significant genotype × environment variation and indicated that the stability of the genotype was mainly affected by the genetic background of the material. A positive association was noticed between per se performance and gca effects, heterobeltiosis and sca, and heterobeltiosis and mean of hybrids as the environment's yield potential increased. The majority of the Bt hybrids showed positive heterosis over a better parent. Among the two versions of Bt transgenic cotton, BGI excelled in per se performance and gca and sca effects for seed cotton yield either in the homozygous form or hemizygous hybrids. Core Ideas: Transgenic cotton (MON531, BGI and MON15985, BGII) is a fast‐growing technology in the world.The stability of combining ability and heterosis using Bt cotton materials helps to develop hybrid programs.Genetic background, Bt cotton event, and environment play key to realizing higher‐yielding genetically stable hybrids.Bt cotton enhances the general stability of the hybrids due to its resistance to bollworms. [ABSTRACT FROM AUTHOR]

Six cotton lines and five testers were crossed in a line x tester mating design in 2019. Thereby hybrids along with 11 parents and a standard check were evaluated for combining ability and standard heterosis. Observations on sympodial branches per plant, the number of bolls per plant, boll weight, Ginning Out Turn, staple length and seed cotton yield per plant were recorded. Among the parents, GJHV 534, TVH 002, NDLH 32, TCH 1894 and RAHC 1040 displayed higher positive gca effects for the number of bolls/plant, sympodial branches/plant, span length, seed cotton yield and ginning outturn percentage. Such results suggested that all these five parents were good general combiners covering the yield contributing traits studied and may be preferred for hybridization and selection programmes. The crosses viz., TVH 002 x RAHC 1040, GJHV 534 x RAHC 1040 and TCH 1894 x NDLH 32 with higher estimates of sca effects for almost all the traits and also were observed with higher heterotic effects. Thus these hybrids could be potential hybrids for the exploitation of heterosis in cotton. [ABSTRACT FROM AUTHOR]

Diversity analysis of Bt lines, a prerequisite to heterosis breeding, are rarely published. Diversity analysis of 140 cotton genotypes comprising of BGI, BGII and Non-Bt lines resulted in the grouping of genotypes into 20 clusters among which five had multiple genotypes and 15 others were solitary. Specific clustering of genotypes of BGI and BGII was not observed which got distributed across the clusters. The maximum and minimum inter-cluster distances were observed between two solitary clusters XVI and XVIII (159.8) as well as clusters VII and XI (6.4), respectively, reflecting diverse and close relationship among the Bt genotypes of those clusters. Two pairs of isogenic lines were located in the same clusters as they shared the same genetic background. The genetic background played important role in the diversity rather than the Bt status of genotype. Also, the maximum genetic diversity (64%) was arising from traits which were not related to Bt genes such as plant height, boll weight, and ginning out-turn when compared to the characters related to Bt gnes such as seed cotton yield and boll number (33%). In general, for seed cotton yield, BGI outperformed BGII lines. The study helped in developing high yielding hybrids through diverse parental line selections. [ABSTRACT FROM AUTHOR]

The cotton variety CO 18 (culture TCB 37) is a Gossypium barbadense variety identified for release by Tamil Nadu Agricultural University, Coimbatore during 2020. This variety was developed at the Department of Cotton, through selection from EC 101786. This variety recorded a mean seed cotton yield of 872 kg/ha as against 621 kg/ha of the Zonal check variety Suvin under irrigated condition. The percentage increase in seed cotton yield was 40.4 per cent. The variety has a yield potential of 1720 kg/ha as has been recorded in Rahuri centre during 2017-18. The variety has recorded an Upper Half Mean Length (UHML) of 35.1 mm, micronaire of 3.5 µg/inch and bundle strength of 36.2 g/tex in HVI mode. The variety recorded a mean boll weight of 3.1 g/boll, is superior to check Suvin and qualifying varieties (GSB 41 and ARBB 1302). CO18 combines high yield potential, big boll size and basic tolerance to pests and diseases. The culture TCB 37 was identified for release as CO 18 by Central Variety Identification Committee during 2020 and the farmers will be highly benefitted by cultivating this variety. [ABSTRACT FROM AUTHOR]

The present study was carried out in inter-specific cotton hybrids of G. hirsutum x G. barbadense to evaluate the extent of heterosis and combining ability for eight yield and fibre contributing traits. Twenty four interspecific hybrids derived from four different lines of G. hirsutum and six testers of G. barbadense were assessed for various parameters. Significant heterosis was recorded for the traits under study suggesting that the existence of genetic diversity among parental lines. The hybrid CO16 x RHCB 1014 exhibited significant positive standard heterosis for seed cotton yield per plant followed by CO15 x TCB26 and SVPR6 x DB1602. The hybrid CO15 x CO18 was the best for the number of bolls per plant, plant height and ginning outturn, while, SVPR6 x DB1602 was the best for UHML and bundle strength. Combining ability analysis exhibits the non-additive gene action in all yield contributing and fibre quality traits. The three lines viz. CO16, MCU7, SVPR 6 and four testers viz.TCB26, DB1602, CCB 143B and CO18 were noted as the best combiners. The hybrids CO16 x CCB 143B, CO16 x DB1601, CO15 x TCB26 and SVPR6 x DB1602 were identified as the best specific combiners and are suggested for advanced breeding programs. [ABSTRACT FROM AUTHOR]

Cotton is a very important crop that consists of traits with different associationship due to genetic and environmental factors. In order to determine the degree of association between seed cotton yield and important traits, a study was done using an RBD experiment with 30 hybrids. Seed cotton yield, plant height, GOT, number of sympodial braches, boll weight, bolls per plant, span length, fineness and strength data were collected and analysed. The experiment was done with 30 F1 hybrids have delivered through Line x Tester mating configuration utilizing six lines and five testers were planted in a Randomized Block Design (RBD) with two replications at the Department of Cotton, TNAU, Coimbatore. Seed cotton yield per plant was found to have significant positive genotypic connection with boll weight (0.5810), number of bolls per plant (0.3867), plant height (0.422) and ginning percent (0.2182) however altogether and contrarily related with consistency proportion at genotypic level. The phenotypic relationship esteems likewise uncovered that seed cotton yield per plant had highly huge and positive phenotypic connection with number of bolls per plant (0.3470) and boll weight (0.4763). Path coefficients were processed to assess the commitment of individual characters to yield in cotton. The way investigation demonstrated high certain immediate impact of number of bolls per plant (0.4743) and fiber strength (0.6880) on seed cotton yield. Micronaire value displayed high sure circuitous impact on seed cotton yield through range length (0.3393), the outcome showed that number of bolls per plant had a high sure relationship with seed cotton yield and sympodial per plant recorded low certain connection with seed cotton yield. It was therefore concluded that selection of high yielding cotton hybrids could emphasize more on lint yield, boll weights, plant height and bolls per plant for better-performing lines. Gin outturn and fibre strength could be used indirectly to improve seed cotton yield through other traits. [ABSTRACT FROM AUTHOR]

The cotton compact variety CO 17 (culture TCH 1819) is a short duration genotype (125-130 days) with synchronized boll maturity suitable for high density planting system (HDPS) was released by Tamil Nadu Agricultural University, Coimbatore during 2020. This variety was developed at Department of Cotton, TNAU, Coimbatore through hybridization involving Khandwa 2 and LH 2220 followed by pedigree breeding. The variety possesses zero monopodia with short sympodial length and is highly suited for high density planting system. It recorded an average seed cotton yield of 2361 kg/ha which is 18.9% increase over the check variety Suraj (National check entry identified for HDPS). Culture TCH 1819 recorded seed cotton yield of 3427 kg/ha which was 21.7 % increase over Suraj and 29.0 % increase over MCU 7 under rice fallow condition. It recorded seed cotton yield of 2051 kg/ha which was 13.8 % increase over Suraj under summer irrigated conditions and also recorded 1604 kg/ha of seed cotton yield under winter rainfed which was 20.1 % increase over the check Suraj. This culture was also evaluated in All India Coordinated Cotton Improvement Project trials for two years during 2016-17 and 2017-18 across ten locations. It registered seed cotton yield of 1850 kg/ha which was 37.9 % increase over Suraj.TCH 1819 culture recorded Upper Half Mean Length (UHML) of 27 mm with bundle strength of 26.9 g/tex. It can spin upto 40's counts. [ABSTRACT FROM AUTHOR]