ABSTRACT Drought stress reduces soybean [Glycine max (L.)] yield stability in tropical environments, particularly from flowering to pod formation. This study aimed to identify adaptive traits and underlying mechanisms of tropical soybean lines under water-limited conditions, as well as to assess the selection potential under non-stress environments. Twenty-five high-yield soybean genotypes carrying the long juvenile (lj) and pod dehiscence1 (pdh1) genes were selected and evaluated under normal (± 80 % of the field capacity - FC) and water-deficit (± 50 % FC) conditions. Two potentially tolerant (which demonstrated a higher capacity to maintain physiological performance and metabolic stability under water deficit) and two susceptible genotypes were identified for further in-depth evaluation. Proline and malondialdehyde (MDA) were negatively and significantly correlated with grain yield under normal and water-deficit conditions. Both characters showed high broad-sense heritability across the environments, indicating strong genetic control and stable phenotypic expression. The simultaneous increase of proline and MDA is associated with reduced grain yield, indicating a stress-induced metabolic trade-off in which carbon and energy are redirected from reproductive development toward cellular protection mechanisms in the soybean genotypes.
Drought tolerance is a polygenic character controlled by polygenes and very difficult to study the gene action by line x tester analysis for improvement of drought related traits. In this situation, the present study was conducted to identify gene effects in rice for drought and yield contributing characters under drought condition by generation mean analysis. The six generations viz., P1, P2, F1, F2, BC1 and BC2 were generated in three crosses viz., PMK 4 x ADT 45, Norungan x ASD 16 and Nootripathu x Co 51. Moisture stress was imposed during 30 days after planting by withholding irrigation. During drought period, the condition of the soil was dry and fragmented. Data on yield and drought contributing traits were recorded for all six generations. The results revealed that, among the main genetic effects, dominance was positively expressed in all characters except three traits (leaf rolling, days to first flowering and harvest index). In the present study, the dominance gene effects and dominance x dominance genetic effects were predominant for grain yield and major yield contributing characters joined with duplicate type of epistasis. For enhancement of these characters, selection will be postponed to later on generations or bi-parental mating of breeding method may be followed. An additive gene effect was also significantly positive for all the characters under study. In addition, additive x additive genetic effects also significant and positive for most of the characters. In the present study revealed that, complementary gene effect was observed in drought related trait leaf rolling in all three crosses, number of grains per panicle and spikelet fertility in one cross (PMK 4 x ADT 45). Complementary epistasis was expressed in the cross Norungan x ASD 16 for harvest index. In this situation, additive gene effects were predominant. For improvement of these traits, simple selection procedure and pedigree methods of breeding to be followed.
S. Ganapathy, S. Suganthi, P. Arunachalam· Plant Science Today· 0 citations
Drought is a major abiotic stress that severely limits cotton productivity by reducing growth, yield, and fiber quality. Understanding genotype-specific responses to reproductive-stage drought is essential for identifying reliable selection traits and improving drought resilience in cotton breeding programs. This study evaluated 54 cotton genotypes at the flowering stage under three irrigation regimes: well-watered conditions (80% FC), mild drought stress (60% FC), and severe drought stress (40% FC). Morphological traits (root and shoot biomass), physiological traits (photosynthetic rate, leaf water loss, and relative water content), and biochemical traits (proline, soluble sugars, amino acids, antioxidant enzyme activities, and reactive oxygen species) were assessed. Drought treatments were imposed for three consecutive weeks during flowering to investigate genotype responses to varying levels of water deficit. The experiment was conducted in a rain-out shelter using a factorial completely randomized design (CRD) with three replications for each genotype–treatment combination. Cotton accessions were grown in plastic containers. Significant genotype-dependent variation was observed across all drought treatments, with responses becoming more pronounced under severe stress. Two-way analysis of variance revealed that drought significantly affected all measured traits. Descriptive statistics and boxplot analyses further illustrated variations in trait performance among genotypes under different stress levels. Principal component analysis (PCA) revealed clear phenotypic divergence among genotypes and highlighted trait associations under contrasting water regimes. Heatmap analysis further confirmed genotype grouping patterns and their relationships with the evaluated traits. Moreover, MGIDI-based selection at 15% selection intensity identified G
33
(FH-901), G
50
(N-1048), G
53
(N-135), G
36
(FH-Super-Cotton), G
29
(FH-556), G
47
(MNH-1035), G
54
(N-135-BB-121/38), and G
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(IUB-13) as drought-tolerant genotypes based on their lower MGIDI values and favorable performance. These genotypes exhibited superior performance, greater water retention, lower oxidative damage, and stronger antioxidant defense systems under water-deficit conditions. The findings provide valuable insights for cotton breeding programs aimed at developing drought-resilient cultivars and support sustainable cotton production in water-limited environments.
M. Y. Shani, A. Ditta, Muhammad Kashif Riaz Khan· Scientific Reports· 0 citations
Developing drought-tolerant forage legumes adapted to saline-sodic soils is essential to sustaining livestock production in marginal environments. Pre-breeding programs allow the identification of useful genetic variation within naturalized populations for this purpose.
This study aimed to (i) compare the performance of half-sib families (HSFs) from a naturalized population of Lotus tenuis, with a commercial cultivar under drought stress, and (ii) identify key traits and promising materials for breeding.
Twenty HSFs and one cultivar were evaluated under controlled conditions in a factorial design with two water regimes (field capacity and drought). Morphological, physiological and biochemical traits were measured, including aerial dry biomass, number of branches, leaf temperature, ion concentrations (Na+, K+), relative water content and oxidative stress indicators. Narrow-sense heritability and genetic correlations were estimated, and multivariate analyses were performed.
Drought significantly reduced growth and altered physiological traits, with differential responses among genotypes. Some HSFs matched or exceeded the cultivar for aerial biomass production under stress. High heritability (h2 > 0.8) was observed for aerial biomass, number of branches, leaf temperature and ion concentrations under drought. Growth traits were positively correlated and negatively associated with leaf temperature and Na+.
Five HSFs (9, 12, 13, 16, and 20) were identified as promising materials on the basis of their performance for aerial biomass, leaf temperature, and Na+ concentration, traits identified as reliable selection criteria for drought tolerance under saline-sodic soil conditions in L. tenuis.
These families provide valuable resources for breeding drought-tolerant cultivars for saline drylands, although further selection and recombination are required.
Lorena del Rosario Marinoni, I. G. dos Santos, P. Tomás et al.· Crop & Pasture Science· 0 citations
Field peas (Pisum sativum L.) withstand short-term drought stress; however, prolonged water deficiency causes a significant reduction in grain yield, reported up to 25%. Drought tolerance is a complex mechanism involving the morphological, physiological, molecular, and cellular mechanisms. This study aimed to quantify genetic variability and identify key physiological traits governing drought tolerance in field pea under contrasting water stresses. Thirty-six pea genotypes were utilized to determine the inheritance of drought tolerance using a completely randomized design (CRD). Key traits evaluated include plant height, leaf area, days to fifty percent flowering, root length, shoot to root ratio, chlorophyll content, electrolyte leakage, relative water content, and proline accumulation. Highly significant differences (P ≤ 0.01) were observed for all traits, indicating substantial genetic variability. Plant height, root length, relative water content, and chlorophyll content exhibited high GCV, heritability, and genetic advance, indicating strong additive gene action and suitability for selection. Under drought stress, physiological traits including relative water content, leaf area, and chlorophyll content remained key contributors to variability, as confirmed by principal component analysis. Findings revealed a strong positive correlation among root length, leaf area, and relative water content, highlighting their collective role in drought tolerance. In contrast, yield per plant showed weak and inconsistent correlations under stress, suggesting its complex inheritance and dependence on multiple interacting traits. This weak association of yield with individual traits under severe stress suggests that indirect selection through key physiological traits may be more effective for improving productivity under drought conditions. Traits such as root length, relative water content, and chlorophyll content can be effectively used for selecting drought-tolerant genotypes.
Muhammad Kamran, T. Hussain, A. Manzoor et al.· Journal of Genetics and Appl...· 0 citations
Yield losses due to water-deficit (WD) conditions, especially during the reproductive stages of plant development, pose a significant threat to global canola (Brassica napus L.) production. Therefore, it is critical to investigate traits contributing to improved productivity under increased WD conditions. Here we present phenotypic, physiological and transcriptomic changes in response to WD across contrasting canola accessions exhibiting variation in drought resistance-related traits. WD significantly reduced shoot biomass, plant height, harvest index, leaf water content, photosynthetic CO2 assimilation rate, intrinsic water-use efficiency and carbon isotope discrimination. WD caused 49 to 100% of the seed yield reduction: the minimum seed yield reduction (49.66%) was observed in a doubled-haploid (DH) line, 06-5101.137, while the maximum yield reduction (94.1 to 100%) occurred in the late-flowering DH lines (06.5101.088 and 06-5101.306). Seed yield showed a positive correlation (r = 0.29 to 0.95) with shoot biomass and harvest index, leaf water content, photosynthetic CO2 assimilation rate, intrinsic water use efficiency and carbon isotope discrimination. However, it showed negative correlations with days to flower, leaf specific weight, root length, root biomass (r = −0.04 to −0.79) across water treatments. The specific leaf transcriptome analysis of the two parental lines of DH population that exhibit variation for effective water use under well-watered and water-deficient conditions revealed different categories of differentially expressed genes (DEGs): WD-responsive DEGs in BC1329 parental line (1116) and BC9102 (1205) with 754 and 853 DEGs unique to BC1329 and BC9102, respectively, WD-responsive DEGs (906), genotype-dependent DEGs (8465) and genotype × treatment interaction DEGs (353). DEG annotations revealed that the WD-treatment-affected genes were involved in stress responses and growth and development. We further located 235 DEGs within the QTL regions underlying agronomic and physiological performance. Our study provides a conceptual framework for the morphological, physiological and molecular determinants involved in water-use efficiency. Seedlings’ traits with high heritability values, such as shoot biomass, leaf weight, leaf water content and Δ13C, serve as proxies for trait-based selection for improved seed yield under both water-limited and non-water-limited conditions.
H. Raman, B. McVittie, Niharika Sharma et al.· International Journal of Mol...· 0 citations
Background: Wheat (Triticum aestivum L.) seedling performance under heat and drought stress is critical for crop establishment. Identifying cultivars with superior seedling vigor under stress conditions helps breeding programs and seed production systems. Methods: We aimed to evaluate the early growth performance of wheat seedlings from 28 Brazilian commercial cultivars under heat and osmotic stress. Seedlings were assessed through shoot and root lengths and dry weight and analyzed using Scott–Knott grouping, heritability estimates, PCA and stress tolerance index. Results: Osmotic stress affected a wider range of traits than heat stress and revealed phenotypic and genetic variability among cultivars. Root length and root dry weight exhibited high broad-sense heritability, indicating a substantial genotypic contribution under the tested conditions and supporting their use for early-stage screening. Multivariate analyses revealed contrasting adaptation strategies, including root elongation and preferential allocation of biomass to roots under stress conditions. Through uni- and multivariate analyses, we suggested cultivars are potentially tolerant to heat and osmotic stresses. Conclusions: Root-related traits proved to be the most informative indicators of adaptation to stress, and the integration of stress tolerance indices and multivariate analyses enabled the identification of promising cultivars for further validation under greenhouse and field conditions.
Antônio de Azevedo Perleberg, Julio Cesar Paes Jacome de Araújo, Thaís Monteiro Miranda et al.· Seeds· 0 citations
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