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Abstract The development of genotypes that can tolerate high levels of salt is crucial for the efficient use of salt-affected land and for enhancing crop productivity worldwide. Therefore, incorporating salinity tolerance is a critical trait that crops must possess. Salt resistance is a complex character, controlled by multiple genes both physiologically and genetically. To examine the genetic foundation of salt tolerance, we assessed 16 F1 hybrids and their eight parental lines under normal and salt stress (15 dS/m) conditions. Under salt stress conditions significant reduction was observed for plant height (PH), bolls/plant (NBP), boll weight (BW), seed cotton yield (SCY), lint% (LP), fiber length (FL), fiber strength (FS), potassium to sodium ratio (K+/Na+), potassium contents (K+), total soluble proteins (TSP), carotenoids (Car) and chlorophyll contents. Furthermore, the mean values for hydrogen peroxide (H2O2), sodium contents (Na+), catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and fiber fineness (FF) were increased under salt stress. Moderate to high heritability and genetic advancement was observed for NBP, BW, LP, SCY, K+/Na+, SOD, CAT, POD, Car, TSP, FL, and FS. Mean performance and multivariate analysis of 24 cotton genotypes based on various agro-physiological and biochemical parameters suggested that the genotypes FBS-Falcon, Barani-333, JSQ-White Hold, Ghauri, along with crosses FBS-FALCON × JSQ-White Hold, FBG-222 × FBG-333, FBG-222 × Barani-222, and Barani-333 × FBG-333 achieved the maximum values for K+/Na+, K+, TSP, POD, Chlb, CAT, Car, LP, FS, FL, PH, NBP, BW, and SCY under salt stress and declared as salt resistant genotypes. The above-mentioned genotypes also showed relatively higher expression levels of Ghi-ERF-2D.6 and Ghi-ERF-7A.6 at 15 dS/m and proved the role of these ERF genes in salt tolerance in cotton. These findings suggest that these genotypes have the potential for the development of salt-tolerant cotton varieties with desirable fiber quality traits.

Salt-affected areas are increasing at a rapid rate that are decreasing agricultural productivity. For this purpose, 6 salt-tolerant and 3 salt-sensitive parents were crossed in a Line × Tester fashion and were sown under control, 10 and 15 dSm−1 salt stress for 2 years. Data were recorded for various biochemical, agronomic, and fiber quality traits like H2O2 (hydrogen peroxide), SOD (superoxide dismutase), POD (peroxidase), CAT (catalase), TSP (total soluble proteins), K+ (potassium), Na+ (sodium), potassium to sodium ratio (K+/Na+), plant height, number of bolls, boll weight, seed cotton yield, GOT% (ginning out turn) fiber fineness, fiber length, and fiber strength. Mean values of plant height, number of bolls, boll weight, seed cotton yield, K+, K+/Na+, fiber fineness, fiber length, fiber strength, antioxidants’ activities showed significant reductions under salt stress. Contrarily, Na+, GOT%, H2O2, TSP and POD activity increased under salt stress, and this effect was more profound under 15 dSm−1. KEHKSHAN × FH-114 remained outstanding in both years and was found salt-tolerant genotype which can be effectively used in future breeding program.

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.

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.

To understand the effect of heat stress on morphology and physiology of the cotton, eight cotton genotypes with their 15F1 hybrids (five lines, three testers) were grown in the field conditions under randomized complete block design (RCBD) with two treatments i.e. normal and high-temperature stresses with two replications followed by split-plot arrangement. Data were collected for biochemical and yield-related parameters. Mean values of all studied traits were reduced significantly under high-temperature stress whilst the mean value of lint%, catalase activity, total soluble proteins, peroxidase, and carotenoids were increased under high-temperature. Under both conditions, the number of bolls, boll weight, seed cotton yield, lint index, seed mass per boll, hydrogen peroxide content, catalase activity, total soluble proteins, carotenoids, and chlorophyll contents had high heritability values along with high genetic advance percent mean which revealed, these traits were controlled by additive gene action. The lint%, seed index, short fiber index, fiber strength, fiber fineness, upper half mean length and peroxidase activity had high heritability with moderate genetic advance under heat stress conditions which showed, these traits were controlled by non-additive gene action. Under both temperature conditions, FH-458, IUB-65, CRS-2, and FH-313 were good general combiners for physicochemical and yield-related traits. The cross combination of IUB-013× CRS-2 and FH-458× FH-313 were good specific combiner for plant height and seed cotton yield whilst for fiber quality and biochemical traits, the best specific combiners were VH-329× FH-313 and IUB-013× CRS-2. These identified parents and cross combinations might be used for improving already present commercial varieties under high-temperature stress.