Coordinated carbon gain and water use are central to rice yield formation, yet cultivar differences are often interpreted from single physiological traits. Here, we evaluated eight rice cultivars at the Longjing experimental station in Hunchun, northeastern China, and measured leaf gas-exchange traits across major growth stages, including net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO₂ concentration (Ci), transpiration rate (E), water-use efficiency (WUE) and light-use efficiency (LUE). Principal component analysis and K-means clustering identified three dominant photosynthetic capacity–transpiration coordination types: low-photosynthetic capacity/high-transpiration (LH), high-photosynthetic capacity/low-transpiration (HL) and low-photosynthetic capacity/low-transpiration (LL). Trait divergence was strongest around heading, when photosynthetic activity and stomatal regulation were most pronounced. Stage-specific weather responses further indicated that precipitation was mainly associated with variation in E, whereas temperature differentiated Gs among types. At the cultivar scale, Yanda 802, assigned to the HL type, showed the highest grain yield, whereas the LL cultivars showed the lowest yields. These results suggest that cultivar-level yield variation was associated with coordinated regulation of photosynthesis, stomatal conductance and water use, rather than enhancement of a single trait alone.
Drought stress poses significant challenges to rice production, necessitating precise, non-invasive phenotyping tools for identifying resilient genotypes. The present study evaluated storage energy (SE) and thermal diffusivity (TD) in three rice varieties (F-67, F-68, and F-2000; 120 plants, with 20 per variety × substrate combination) grown under alternate wetting and drying conditions in two contrasting substrates: control soil-substrate and coconut peat substrate. The term SE denotes the fraction of absorbed light energy stored in photosynthetic products. In contrast, TD is a measurement of the rate of heat propagation through leaf tissue. This parameter is directly linked to tissue structure and leaf water content. Measurements employed the photoacoustic technique with frequency-modulated light (21–47 Hz) to probe depth-dependent leaf energy dynamics. Statistical analyses, including analysis of covariance with days after transplanting as a developmental covariate, revealed significant substrate effects on both SE and TD, with coconut peat-grown plants exhibiting lower SE and TD, consistent with reduced water stress. Treatment period significantly influenced both parameters, with prolonged water deficit producing the most pronounced physiological responses. After excluding sampling day, optimized machine learning (ML) classification achieved an overall treatment-period accuracy of 70
Soil salinity is a major abiotic factor that adversely affects crop growth and productivity worldwide. Endophytic fungi associated with halophytic plants represent a promising source of salt-tolerant microorganisms with potential applications in sustainable agriculture. Endophytic fungal isolates obtained from the roots, stems, and leaves of Acanthus ilicifolius were screened for salt tolerance, antioxidant activity, total phenolic content, and plant growth-promoting traits. Among the salt-tolerant isolates, the root-derived isolate AIR2 exhibited notable antioxidant and plant growth-promoting attributes and was therefore selected for further characterisation. Molecular identification based on ITS sequence analysis identified AIR2 as Epicoccum dendrobii. Inoculation with E. dendrobii AIR2 improved rice growth under salinity stress, as evidenced by increased root and shoot growth, biomass, relative water content, and photosynthetic pigment levels compared with the corresponding non-inoculated salt-stressed plants. AIR2 inoculation also enhanced proline accumulation and modulated antioxidant enzyme activities, while reducing malondialdehyde (MDA) accumulation, indicating improved osmotic adjustment and mitigation of salinity-induced oxidative damage. In addition, AIR2 exhibited antifungal activity against the plant pathogens Alternaria alternata, Botrytis cinerea, Fusarium oxysporum, and Rhizoctonia solani, with inhibition reaching up to 64
Sesame production in Cameroon is increasing steadily, especially in the country’s northern regions. This study aimed to analyze the agronomic performance and oil quality of 28 sesame collections using an alpha-lattice design with three replicates at Omog, central Cameroon. Agro-morphological traits [plant height (PH), number of branches per plant (NBP), number of capsules per plant (NCP), number of seeds per capsule (NSC), and 1000-grain weight (1000-GW)] and biochemical indicators of oil quality (oil content, acid index (IA), saponification index (IS), ester index (IE), iodine index (II), and peroxide index (IP)] were used to estimate genetic variability. SH-ESS has the maximum PH (213.90 cm), but the lowest 1000-GW (1.55 g). SH-LAI had the greatest oil production and IP (88.37
Yellow (stripe) rust, caused by Puccinia striiformis f. sp. tritici, remains a major constraint to bread wheat production. In the present study, 68 wheat genotypes were evaluated under epiphytotic field conditions and characterized using 38 Yr-linked molecular markers to assess genetic diversity and its correspondence with disease response. Field evaluation identified 53 resistant, three trace-resistant, seven moderately susceptible, four susceptible genotypes and one highly susceptible (Infector) line. A total of 100 alleles were scored ranging from 1 to 8 per marker, with an average of 2.63. Polymorphism information content (PIC) ranged from 0.06 to 0.83 (mean ≈ 0.50), while Nei’s gene diversity ranged from 0.057 to 0.85 (mean ≈ 0.55). Xgwm273 was the most informative marker (PIC = 0.83; H = 0.85), followed by Wmc44 (PIC = 0.82; H = 0.84) and Barc101 (PIC = 0.80; H = 0.83). UPGMA clustering based on Jaccard similarity coefficients (0.58–0.95) resolved the genotypes into two major clusters, although resistant and susceptible genotypes were interspersed among different molecular groups. PCA and PCoA further demonstrated substantial molecular heterogeneity within the genotypes. PERMANOVA detected weak but statistically significant differentiation among disease-response groups (F = 1.337; R² = 0.078; P = 0.018), whereas Mantel (r = 0.027; P = 0.577), ANOSIM (R = 0.055; P = 0.194) and chi-square (χ² = 10.95, df = 8, P = 0.205) analyses indicated limited overall correspondence between molecular diversity and yellow rust phenotype. These findings demonstrate the utility of Yr-linked molecular markers for characterizing genetic diversity at resistance-linked genomic regions and identifying genetically divergent resistant parents. However, their application in resistance breeding and gene pyramiding should be complemented by field phenotyping and validated diagnostic markers.
