Lint Weight Research Articles

Assessing the genetic landscape of Kapok (Ceiba pentandra L. Gaertn) progeny trial: a cluster analysis for sustainable natural fibre resources

Ceiba pentandra, commonly known as the kapok tree or silk-cotton tree, exhibits diverse ecological roles, medicinal properties, economic value, and cultural significance. In this context, thirty-plus C. pentandra (kapok) trees were selected from various locations in the Theni and Dindigul districts of Southern Tamil Nadu based on superior traits by using the comparison tree method. Harvested pods provided seeds for establishing a progeny trial to evaluate seed source variation and other associated studies. Eleven traits were examined, including pod length, pod diameter, pod weight, shell weight, lint weight, floss weight, seed weight, number of seeds, tree height, girth at breast height, and number of branches. After two years and seven months, significant variations were observed among the genotypes in terms of biometric parameters and pod attributes of C. pentandra. Most characters, including pod weight, pod length, pod diameter, and floss weight, exhibited high heritability values and substantial genetic advances as a percentage of the mean. Cluster analysis categorized the thirty genotypes into four clusters. Notably, considering floss weight as a pivotal trait due to its significance as an alternate source of natural fibres, genotypes g28, g29, and g30 (originating from Sirumalai, Dindigul) were identified as superior to other genotypes. These genotypes can be utilized for further research programs to study genetic diversity at the genome level using advanced molecular tools.

Impacts of wide row spacings on yield and yield components of upland cotton (Gossypium hirsutum L.)

AbstractThis study quantifies the effects of wide row spacing on lint yield, yield components, and fiber quality of upland cotton (Gossypium hirsutum L.). An experiment was conducted in Tifton, GA in 2021 and 2022, where cotton was planted in six replications of 91‐, 122‐, 152‐, and 183‐cm row spacings. Following defoliation, 1.8 m was hand harvested from each plot, and boll density plant−1 and density ha−1 were determined for sympodial and monopodial branches. Additional measurements included fruit and lint yield distribution assessments and intra‐boll yield components including seed cotton weight boll−1, seed index, seed boll−1, lint weight seed−1, seed surface area (SSA), fiber density, and single fiber weight. Lint yield was reduced 20% in the 183‐cm row spacing compared to the 91‐cm row spacing. The 91‐cm rows had the lowest number of sympodial bolls plant−1 with 152‐ and 183‐cm rows demonstrating a 24%–28% increase in sympodial bolls plant−1. Sympodial bolls ha−1 were reduced 22% in the 183‐cm row spacing compared to the 91‐cm row spacing. There were no differences in bolls ha−1 or lint yield ha−1 with respect to monopodial growth. There were no differences in seed cotton weight boll−1, seeds boll−1, fiber density, single fiber weight, or turnout. Seed index and SSA were increased in the 183‐cm row spacing. Lint weight seed−1 was reduced in the 91‐cm row spacing.

Genome-wide identification of the key kinesin genes during fiber and boll development in upland cotton (Gossypium hirsutum L.).

Kinesin is a kind of motor protein, which interacts with microtubule filaments and regulates cellulose synthesis. Cotton fiber is a natural model for studying the cellular development and cellulose synthesis. Therefore, a systematic research of kinesin gene family in cotton (Gossypium spp.) will be beneficial for both understanding the function of kinesin protein and assisting the fiber improvement. Here, we aimed to identify the key kinesin genes present in cotton by combining genome-wide expression profile data, association mapping, and public quantitative trait loci (QTLs) in upland cotton (G. hirsutum L.). Results showed that 159 kinesin genes, including 15 genes of the kinesin-13 gene subfamily, were identified in upland cotton; of which 157 kinesin genes can be traced back to the diploid ancestors, G. raimondii and G. arboreum. Using a combined analysis of public QTLs and genome-wide expression profile information, there were 29 QTLs co-localized together with 28 kinesin genes in upland cotton, including 10 kinesin-13 subfamily genes. Genome-wide expression profile data indicated that, among the 28 co-localized genes, seven kinesin genes were predominantly expressed in fibers or ovules. By association mapping analysis, 30 kinesin genes were significantly associated with three fiber traits, among which a kinesin-13 gene, Ghir_A11G028430, was found to be associated with both cotton boll length and lint weight, and one kinesin-7 gene, Ghir_D04G017880 (Gh_Kinesin7), was significantly associated with fiber strength. In addition, two missense mutations were identified in the motor domain of the Gh_Kinesin7 protein. Overall, the kinesin gene family seemingly plays an important role in cotton fiber and boll development. The exploited kinesin genes will be beneficial for the genetic improvement of fiber quality and yield.

Genome-wide identification of the key Kinesin genes during fiber and boll development in upland cotton (Gossypium hirsutum L).

Kinesin is a kind of motor protein, which interacts with microtubule filaments and regulates cellulose synthesis. Cotton fiber is a natural model for studying the cellular development and cellulose synthesis. Therefore, a systematic research of Kinesin gene family in cotton (Gossypium spp.) will be beneficial for both understanding the function of Kinesin protein and assisting the fiber improvement. Here, we aimed to identify the key Kinesin genes present in cotton by combining genome-wide expression profile data, association mapping, and public quantitative trait loci (QTLs) in upland cotton (Gossypium hirsutum L.). Results showed that 159 Kinesin genes, including 15 genes of the Kinesin-13 gene subfamily, were identified in upland cotton; of which 157 Kinesin genes can be traced back to the diploid ancestors, G. raimondii and G. arboreum. Using a combined analysis of public QTLs and genome-wide expression profile information, there were 29 QTLs co-localized together with 28 Kinesin genes in upland cotton, including 10 Kinesin-13 subfamily genes. Genome-wide expression profile data indicated that, among the 28 co-localized genes, seven Kinesin genes were predominantly expressed in fibers or ovules. By association mapping analysis, 30 Kinesin genes were significantly associated with three fiber traits, among which a Kinesin-13 gene, Ghir_A11G028430, was found to be associated with both cotton boll length and lint weight, and one Kinesin-7 gene, Ghir_D04G017880 (Gh_Kinesin7), was significantly associated with fiber strength. In addition, two missense mutations were identified in the motor domain of the Gh_Kinesin7 protein. Overall, the Kinesin gene family seemingly plays an important role in cotton fiber and boll development. The exploited Kinesin genes will be beneficial for the genetic improvement of fiber quality and yield.

The Effect of Planting Dates and Planting Methods on Cotton Quantitative and Qualitative Traits in Moderate and Humid Climatic Conditions

otton is one of the most important crops in Golestan Province, Iran. The planting and harvesting date interferes with autumn crops such as wheat. A delay in planting cotton causes a decrease in yield. Transplanting cultivation can help to solve this problem. For this purpose, an experiment was carried out during two crop years in 2017 and 2018 in Iran, Golestan Province, Gorgan city, research station of Iraqi Mahlah in the form of a split plot based on randomized complete blocks design in four replications. Experimental treatments including planting dates at three levels including; Planting dates were May 27, June 16 and July 7 and planting methods were in seven levels (6 treatments using Transplanting and direct seeding methods). Quantitative traits including plant height, number of bolls per plant, lint weight per boll, lint yield and biological yield were measured along with cotton qualitative traits such as fiber length, stretch percentage, fiber fineness, fiber strength and uniformity index. Based on the results, the simple effect of planting dates, planting methods, as well as the interaction effect of planting dates × planting methods on all quantitative and qualitative traits were significant. Also, the interaction effect of year × planting date × planting method on the number of bolls per plant and biological yield was significant. The average lint yield in transplanting methods was 2256 kg per hectare and showed an increase of about 37% compared to direct seeding cultivation method. The best cultivation method it was that one with one seedling transplanted, the distance between the rows=75 cm and the distance on the rows=40 cm, the yields being higher as compared to other treatments. In general, the lint yield in direct seeding was much lower than the lint yield in transplanting cultivation. Also, the quality traits were affected by planting dates and planting methods, and in most cases, cotton quality traits were improved in the transplanting cultivation method. Therefore, if the cost of producing and transporting seedlings is economical, cotton transplanting is preferable to direct seeding cultivation.

Effect of Irrigation Regimes and Nitrogen Levels on Growth and Yield of Cotton Genotypes Under Climate of Multan

Nitrogen use efficiency (NUE) and water scarcity are the biggest problems in the agriculture sector. These problems can arise in arid and semi-arid areas with water scarcity and low soil fertility. Cotton in south Punjab faces these problems during growth and development stages, so the yield results are lower than in other cotton-producing regions. This study was designed to assess the potential of different cotton genotypes grown on various water and nitrogen (N) applications. This study involves seven cotton crop genotypes with three irrigation levels, i.e., 18, 13, and 9 irrigations with N application at 200, 250, and 300 kg ha-1 under randomized complete block design (RCBD) factorial arrangement with three replications of each treatment. The data regarding plant growth, yield, and physiology was collected. The results indicated that Genotype IUB-13 showed a higher N uptake of 0.84% among the other seven genotypes tested at (T2). Among the seven genotypes tested, NAIB-878 demonstrated a significantly higher value of lint weight 1200 g in block-1 and T2. The finding of this study concluded that higher N levels under deficit irrigation could help to reduce the yield gaps by increasing the growth of cotton genotypes under the climatic conditions of Multan.

Impact of intra‐boll yield components on lint production per boll and fiber quality in advanced cotton breeding lines

AbstractCotton (Gossypium hirsutum L.) lint yield and fiber quality are associated with various yield components. Research efforts addressing intra‐boll yield component contributors to lint production boll−1 are limited. Thus, a study was conducted in Tifton, Georgia with the objectives to quantify the contributions of intra‐boll yield components to lint production boll−1 and to identify yield components most strongly associated with lint production boll−1 in advanced breeding lines of upland cotton. Data collected included intra‐boll yield components and fiber quality parameters. A strong association was observed between lint production boll−1 and seedcotton weight boll−1 (r = 0.896) compared to lint production boll−1 and lint percent (LP, r = 0.574). For breeding lines with maximum lint weight boll−1, the contribution of seedcotton weight and LP ranged from 0.17 to 0.36 g boll−1 and 0.22 to 0.24 g boll−1, respectively, suggesting a relatively greater influence of seedcotton weight boll−1 on lint weight boll−1. Lint production boll−1 can be expressed as the product of seeds per boll, seed surface area, fiber density (FD), and individual fiber weight (IFW). IFW was the greatest contributor to lint production boll−1 for seven breeding lines and FD for nine breeding lines. A strong positive association was observed between lint production boll−1 and IFW (r = 0.656, p < 0.001); however, no significant association between lint weight boll−1 and FD suggesting a relatively greater influence of IFW on lint weight boll−1. Our work provides future direction aimed at improving lint yields through the selection of various yield components.

Inheritance of Lint Weight Per Boll in Specific and Interspecific F1, F2 Hybrids in Cotton

The experiment aimed to study the inheritance patterns of lint weight per boll in F1 and F2 hybrids. The parental forms, including varieties and lines, were reciprocally hybridized to analyze the impact on lint weight per boll. The results showed variations in lint weight among the parental forms and their hybrids. No heterosis was observed in F1 hybrids with similar lint weight per boll. Positive and negative dominance patterns were identified in F1 hybrids involving different parental forms. In F2 hybrids, transgressive variability and genetic contributions were observed, indicating potential for selection and breeding. The results suggest that distant parental forms and gene combinations influence the lint weight per boll in subsequent generations.

Quantifying physiological contributions to nitrogen-induced yield variation in field-grown cotton

The effect of nitrogen (N) application rate on lint yield and yield components have been studied extensively in cotton. However, reports quantifying contributions to N-induced yield loss and the response of intra-boll yield components to N deficiency are far less common. The objectives of this study were to 1) determine the effect of N application rate on lint yield biomass and fiber quality in cotton, 2) assess the contributions of intercepted photosynthetically active radiation (IPAR), radiation use efficiency (RUE), and harvest index (HI) to N-induced yield loss in cotton, and 3) characterize the effect of N application rate on yield component responses in cotton. An experiment was conducted at a field site near Tifton, Georgia, USA during the 2021 and 2022 growing seasons. The experiment was arranged as a randomized complete block design with five replications and five nitrogen application rates (0, 44, 89, 134, and 179 kg N ha−1). The studied parameters were lint yield, IPAR, RUE, HI, fiber quality, yield components, and yield loss contributions. Lint yield was significantly affected by N application rate, with yields ranging from 1452 to 1848 kg ha−1. Similarly, total IPAR was 23% lower for the 0 kg N ha−1 treatment than the 134 kg N ha−1 treatment, and IPAR contributed significantly to yield loss, with a 427 kg ha−1 loss attributable to IPAR under N deficiency. RUE was 37% higher for the 179 kg N ha−1 treatment than the 0 kg N ha−1 treatment and contributed positively to yield in the highest N rates (179 kg N ha−1). However, yield improvements due to RUE were mitigated by low HI values in the highest N application rate. Boll density was the most strongly and positively associated yield component parameter with N-induced variability in lint yield, whereas lint percent and lint production per seed were negatively associated with lint yield. Among the three physiological yield-driving parameters, light interception by the canopy was the primary contributor to N-induced yield loss. Boll density was the primary yield component governing N-induced variation in lint yield. Increased N application rate promotes greater dry matter partitioning to seeds than fiber, resulting in more seeds per boll and lower lint percent, lint weight per seed, and individual fiber weight. The results contained here identify the most important functional traits for determining lint yield response to N application rate.

Effect of Reproductive Stage-Waterlogging on the Growth and Yield of Upland Cotton (Gossypium hirsutum)

The reproductive stage of cotton (Gossypium sp.) is highly sensitive to waterlogging. The identification of potential elite upland cotton (Gossypium hirsutum) cultivar(s) having higher waterlogging tolerance is crucial to expanding cotton cultivation in the low-lying areas. The present study was designed to investigate the effect of waterlogging on the reproductive development of four elite upland cotton cultivars, namely, Rupali-1, CB-12, CB-13, and DM-3, against four waterlogging durations (e.g., 0, 3, 6, and 9-day). Waterlogging stress significantly impacted morpho-physiological, biochemical, and yield attributes of cotton. Two cotton cultivars, e.g., CB-12 and Rupali-1, showed the lowest reduction in plant height (6 and 9%, respectively) and boll weight (8 and 5%, respectively) at the highest waterlogging duration of 9 days. Physiological and biochemical data revealed that higher leaf chlorophyll, proline, and relative water contents, and lower malondialdehyde contents, particularly in CB-12 and Rupali-1, were positively correlated with yield. Notably, CB-12 and Rupali-1 had higher seed cotton weight (90.34 and 83.10 g, respectively), lint weight (40.12 and 39.32 g, respectively), and seed weight (49.47 and 43.78 g, respectively) per plant than CB-13 and DM-3 in response to the highest duration of waterlogging of 9 days. Moreover, extensive multivariate analyses like Spearman correlation and the principle component analysis revealed that CB-12 and Rupali-1 had greater coefficients in yield and physiological attributes at 9-day waterlogging, whereas CB-13 and DM-3 were sensitive cultivars in response to the same levels of waterlogging. Thus, CB-12 and Rupali-1 might be well adapted to the low-lying waterlogging-prone areas for high and sustained yield.

Seed-score (S-score), a Method for Characterizing Seed and Lint Indices of Cotton Lines

Increased lint yields of cotton (Gossypium hirsutum L.) cultivars during recent years have been accompanied by increased lint percentages and decreased seed size. Small seed size can be associated with low seed and seedling vigor and can contribute to ginning problems. In contrast, large seed size can be associated with thin seed coats and lower lint yields. Our objective was to develop an index that would characterize seed size and lint weight per seed. Seed-score (S-score) attempts to normalize seed index (SI) and lint index (LI) into a single index with penalties for both high and low SI values and no penalty for high LI values. Location × cultivar means (6,453 lines) for SI and LI extracted from the 1999 through 2020 Arkansas Cotton Variety Testing program produced mean SI of 10.17 ± 1.07 g and mean LI of 7.01 ± 0.90 g. These data were used to develop the normalization and weighting of factors for S-score. S-score was then calculated for transgenic cultivars evaluated in the 2015 through 2020 Arkansas Cotton Variety Tests. Within each year, cultivar was the major source of variation for SI, LI, and S-score. The 2015-2017 data set and the 2018-2020 data set produced 12 and 15 common cultivars, respectively. S-score among cultivars varied by more than 25 points in each data set and was relatively consistent over years. S-score will most likely be used as a secondary selection criterion in cotton cultivar development programs.

Effects of Salinity Stress on Some Growth, Physiological, and Biochemical Parameters in Cotton (Gossypium hirsutum L.) Germplasm

ABSTRACT The production of cotton is negatively affected by salinity. For this purpose, 8 parents and their 16 F1 hybrids were evaluated under saline stress (15 dSm−1) in Line × Tester fashion. Mean values of plant height, number of bolls plant−1, boll weight, lint weight, seed cotton yield plant−1, seed index, no. of seeds boll−1, seed mass boll−1, lint mass boll−1, seed volume per 100 seeds, fiber strength, fiber length, lint%, K+, K+/Na+ ratio, CAT, TSP, chlorophyll a, b, and relative water contents decreased under salt stress whilst the values of lint index, seed density, fiber fineness, Na+, H2O2, SOD, POD carotenoids, malondialdehyde, phenolic contents, ascorbic acid, and flavonoids increased under saline conditions. Under saline MS-71× CRS-2007, MS-71× KAHKASHAN, and IUB-65 × FH-312 exhibited performed better than other genotypes for most traits. For fiber quality traits IUB-65× CRS-2007 and IUB-65× FH-312 showed the highest value under salt stress. Improved identified cotton genotypes can enhance our capacity to grow cotton in salt-affected soils and the key morpho-biochemical traits can potentially be exploited to obtain higher and more stable crops yield under stressed environments.

Genetic Variation Studies of Ionic and within Boll Yield Components in Cotton (Gossypium Hirsutum L.) Under Salt Stress

ABSTRACT Cotton (Gossypium hirsutum L.) productivity is decreasing alarmingly by salinity. For genetic analysis of cotton response to salinity 8 parental genotypes and their 16 F1 crosses were evaluated in Line × Tester fashion under normal and salt stress 15 dSm−1. Data were recorded for plant height, number of bolls plant−1, boll weight, lint weight, seed cotton yield plant−1, lint percentage, seed index, lint index, number of seeds boll−1, seed mass boll−1, lint mass boll−1, lint mass per seed, seed volume 100−1 seeds, seed surface area, ionic ratio, fiber strength, fiber length, fiber fineness, GOT %, SOD, POD, CAT, TSP, and H2O2. The results showed that SCA estimates were higher than the GCA indicating the preponderance of non-additive gene action. Kahkashan, MS-71, and CRS-2007 were found good general combiner whereas FH-114 × FH-312 was found the best specific combiner. FH-114 × KAHKASHAN and FH-114 × FH-312 demonstrated significant heterosis for most traits under normal and salt stress conditions. The present study revealed that salt tolerance ability is controlled by a few dominant genes in the identified genotypes.

Foliar enrichment of potassium and boron overcomes salinity barriers to improve growth and yield potential of cotton (Gossypium hirsutum L.)

Foliar application of essential minerals is considered as an economical approach to enhance growth and productivity of crop plants. This study aims to assess the individual and combined effects of potassium (KNO3; K+= 4.5 Kg ha−1) and boron (H3BO3; B3+ = 0.15 Kg ha−1) on growth and yield of salt stressed Cotton (Gossypium hirsutum L. var. CIM 496). Plants were grown in lysimeters and irrigated with 0, 6 and 12 dS m−1 sea salt solutions, for 12 weeks. Foliar application of K+, B3+ and K++B3+ improved plant height and biomass under both non-saline and saline conditions. Foliar enrichment of minerals not only reduced sodium (Na+) entry but also enhanced K+ availability, hence maintained a favorable ion relation (K+/Na+) in photosynthetic tissues. Such regulations along with maintained succulence and production of organic osmolytes (e.g., sugars) helped plant in osmotic adjustment. Salt induced inhibition of reproductive growth was also significantly reverted by foliar application of K+, B3+ and K++B3+. Number of cotton bolls, lint weight, number and weight of seeds and seed cotton yield were significantly improved by K+, B3+ and K++B3+ application. Combined application (K++B3+) showed maximum plant growth and productivity even at higher salinity (12 dS m−1). This approach can be adopted to obtain a considerable crop yield from less productive soils using saline water irrigation and can provide profitable outcomes by converting vast degraded lands into lucrative resources.

A Native Bee, Melissodes tepaneca (Hymenoptera: Apidae), Benefits Cotton Production.

The cotton agroecosystem is one of the most intensely managed, economically and culturally important cropping systems worldwide. Native pollinators are essential in providing pollination services to a diverse array of crops, including those which have the ability to self-pollinate. Cotton, which is autogamous, can potentially benefit from insect-mediated pollination services provided by native bees within the agroecosystem. Examined through two replicated experiments over two years, we hypothesized that native bees facilitated cross-pollination, which resulted in increased lint of harvested bolls produced by flowers exposed to bees and overall lint weight yield of the plant. Cotton bolls from flowers that were caged and exposed to bees, flowers that were hand-crossed, and bolls from flowers on uncaged plants exposed to pollinators had higher pre-gin weights and post-gin weights than bolls from flowers of caged plants excluded from pollinators. When cotton plants were caged with the local native bee Melissodes tepaneca, seed cotton weight was 0.8 g higher on average in 2018 and 1.18 g higher on average in 2019 than when cotton plants were excluded from bees. Cotton production gains from flowers exposed to M. tepaneca were similar when measuring lint and seed separately. Cotton flowers exposed over two weeks around the middle of the blooming period resulted in an overall yield gain of 12% to 15% on a whole plant basis and up to 24% from bolls produced from flowers exposed directly to M. tepaneca. This information complements cotton-mediated conservation benefits provided to native pollinators by substantiating native bee-mediated pollination services provided to the cotton agroecosystem.

Saline water irrigation strategies in two production cycles of naturally colored cotton

Scarcity of good quality water is a limiting factor for irrigated agriculture, especially in a semi-arid region, which induces the use of waters with high salt levels to irrigate crops. As a result, it becomes necessary to use salt tolerant genotypes and appropriate cultivation strategies that enable their production. With this focus, this study was carried out to evaluate the production components of three naturally colored cotton genotypes (‘BRS Rubi’, ‘BRS Topazio’, and ‘BRS Safira’), subjected to various irrigation management strategies, varying the stages of development in which plants were irrigated with saline water. The study also aimed to evaluate the influence of the water salinity level at which seeds were formed, in a new production cycle, using the same irrigation strategies and varying the phenological stages. There were seven salinity management strategies in the first year of cultivation and ten in the second year, both experiments were conducted in a randomized block design. Among the genotypes, ‘BRS Rubi’ was the most tolerant to salinity, with respect to the intrinsic characteristics of the fiber, regardless of the development stage. In the second production cycle, plants grown from seeds formed under salt stress during the stages of flowering and yield formation had increases in lint weight and fiber quality. In the second year, the oil content of the cotton genotypes was not compromised by the cumulative salt stress, considering seeds produced in plants irrigated with saline water in the previous cycle.

Root biomass and production of cotton cultivars subjected to saline water irrigation

Water scarcity and high levels of salinity in irrigation water limit irrigated cotton cultivation in the semiarid region of Northeast Brazil. So, it is necessary to adopt cultivation strategies that make the production system feasible. In this context, the present study aimed to evaluate the biomass and production of cotton cultivars subjected to different levels of saline water irrigation. The experiment was carried out under greenhouse conditions, with treatments distributed in a completely randomized design, in a 5 x 2 factorial arrangement, corresponding to five levels of irrigation water electrical conductivity - ECw (1.5, 3.0, 4.5, 6.0 and 7.5 dS m-1) and two cotton cultivars (BRS 368 RF and BRS Safira), with 4 replicates. Treatment effects were measured by the number of bolls per plant, lint weight, number of seeds per plant, total weight of seeds and dry and fresh biomass of stem, roots and leaves. Irrigation using water with electrical conductivity from 1.5 dS m-1 negatively affects the production of the cotton cultivars BRS SAFIRA and BRS 368 RF, causing reductions in all production variables analyzed. The cultivar BRS Safira has better production performance than BRS 368 RF when exposed to water salinity.

Cytosolic Ascorbate Peroxidases Plays a Critical Role in Photosynthesis by Modulating Reactive Oxygen Species Level in Stomatal Guard Cell

Photosynthetic rate is one of the key factors limiting yield of cotton. Reactive oxygen species (ROS) generated by abiotic stress imposes numerous detrimental effects and causes tremendous loss of yield. It is worth to study whether ROS scavenging enzymes could affect yield through regulating photosynthetic rate in cotton. In this study, we created transgenic cotton with changes of endogenous ROS by overexpressing or suppressing the expression of cytosolic ascorbate peroxidases (APXs), which are hydrogen peroxide (H2O2) scavenging enzymes in plants. The suppression of cytosolic APXs by RNAi brings about a great influence on plant growth and development. Plant height and leaf size declined, and yield-related traits including single boll weight, seed weight, seed size, and lint weight dropped significantly, in IAO lines (cytosolic APX-suppressed lines). The stunted plant growth was due to the decrease of plant photosynthetic rate. The evidences showed that increased ROS level in guard cells inhibited stomatal opening and suppressed the absorption of CO2 and H2O in IAO line. The decrease of water content and the increase of water loss rate in leaf exacerbated the decline of photosynthetic rate in cytosolic APX-suppressed lines. Based on these results, it implies that cytosolic APXs as a whole play an important role in maintaining REDOX balance to regulate photosynthetic rate and yield in cotton.

Response of Boll Development to Macronutrients Application in Different Cotton Genotypes

Combined application of nitrogen (N), phosphorus (P), and potassium (K) is a valuable practice to improve the growth and physiological activities of cotton, especially during a boll setting. The main purpose of this research was to investigate the effects of the different combined ratios of nitrogen (N), phosphorus (P), and K (potassium) on morpho-physiological activities of Bacillus thuringiensis (Bt) cotton genotypes Siza 1 and Sikang 1 during the cotton boll development stage. A two-year (2016–2017) field experiment was performed in which the total amount of combined N, P, and K were applied at different levels, B1 = 150 N, 0 P2O5, and 0 K2O kg ha−1 (control), B2 = 150 N, 45 P2O5, and 90 K2O kg ha−1, B3 = 150 N, 90 P2O5, and 135 K2O kg ha−1, and B4 = 150 N, 135 P2O5, and 180 K2O kg ha−1. Results revealed that combined application of N, P, and K significantly increased boll length by 5.8% and 2.3%, fresh boll weight by 12.2% and 16.4%, dry lint weight by 15.2% and 1.7%, number of seeds boll−1 by 15.2% and 2.5% as well as dry boll shell weight by 11.0% and 4.9% as compared with the treatment without P and K (1:0:0) across two growing seasons. Furthermore, superoxide dismutase activity was improved by 2.3% and 15.6% and soluble protein by 5.1% and 14.1% as compared with the control, respectively. Our study indicated that combined application of N, P, and K at appropriate ratios enhanced morpho-physiological activities (boll length, boll width, boll weight, protein content, sugar content, and superoxide dismutase) of cotton during boll development and generally the ratio of 150:135:180 considerably performed best amongst all treatments during two growing seasons in this study.

Estimation of Gene Action, Heritability and Pattern of Association among Different Yield Related Traits in Upland Cotton

A random mating design comprising 6 varieties (FH-142, MS-DK, IUB-63, KZ-189, FB-3159, and VH-300) and F1 crosses was used to check gene action for yield contributing traits in upland cotton. Heritability and correlation were calculated from F3 populations of the cross CRS-456×Jumbo okra. The randomized complete block design was used in both experiments with three replication at the Department of Plant Breeding and Genetics, University of Agriculture Faisalabad, Pakistan during 2015-2017. In both experiments, analysis of variance indicated significant variation present among the accessions of the upland cotton for all the traits (plant height, sympodial and monopodial branches, nodes number of 1st sympodial branch, height of 1st sympodial branch, bolls per plant, boll weight, lint weight, seed cotton yield, seed index, lint percentage, lint index, seeds per boll, fiber fineness, fiber strength, fiber length and fiber uniformity) under study. Mean values of all genotypes were significantly different from each other for all the traits studied. All the parameters manifested positive correlation with seed cotton yield except plant height, monopodia per plant, nodes number of 1st sympodia, height of 1st sympodia, bolls per plant, seed index and lint index. The inheritance of all the traits in F1 crosses was generally controlled by overdominance gene action except monopodial branches, nodes number of 1st sympodial branch, height of 1st sympodial branches, boll weight, fiber length and fiber uniformity that were partially controlled under additive gene action. Epistasis was not found to be involved in any of the traits. Estimation of broad sense heritability (h2 b. s) in F3 populations were high (60-97%) for all the traits under study. Results suggested form heritability and correlation that these traits can be improved either through appropriate selection method or hybrid breeding programme.