Journal of Agronomy and Crop Science最新文献

Lodging is one of the main limiting factors threatening crop yields. Although the technology to modify plant morphology and improve lodging resistance using plant growth regulators (PGRs) is well developed, the understanding of the effects and underlying mechanisms of PGRs in regulating stem traits at different growth stages of wheat remains limited. In this study, two cultivars, Shidong 0358 (SD0358, a lodging resistant cultivar) and Xindong 18 (XD18, a lodging-sensitive cultivar), were used to investigate the effects of chlorocholine chloride (CCC) and gibberellin (GA₃) treatment on wheat stem characteristics, lodging resistance, lignin and cellulose biosynthesis processes and yield during the jointing and booting stages. The results showed that in the lodging-sensitive cultivar (XD18), exogenous CCC treatment (CC) at the jointing and booting stages shortened the second basal internode during the flowering and filling stages, while increasing lignin and hemicellulose content, stem breakage strength and stem lodging resistance index, resulting in a decrease in wheat lodging rate and an increase in total yield, compared with CK. However, exogenous CCC and GA₃ (CG) treatments during the jointing and booting stages increased the height of the gravity centre of wheat, reduced the activity of 4-Coumaroyl-CoA and Cinnamyl Alcohol Dehydrogenase, resulting in a decrease in cellulose and hemicellulose content, thereby increasing lodging rate. Meanwhile, under CC treatment, the lodging-resistant cultivar (SD0358) showed enhanced stem breakage strength and enhanced yield with advantageous lignin biosynthesis ability. Interestingly, compared to CC, CG treatment showed an increase in cellulose and hemicellulose content in the stem of SD0358 and a further increase in final yield. Overall, the application of CCC during the jointing and booting stages improved stem morphology and quality, thereby enhancing lodging resistance and final grain yield, especially in lodging-sensitive cultivars. The combined strategy of applying CCC during the jointing stage and GA₃ during the booting stage is an effective chemical regulation method to balance lodging resistance and yield potential in lodging-resistant cultivars.

Seedling-water can effectively ensure the survival of sweet potato seedlings after transplanting. However, improper irrigation of acclimation water can lead to an uncoordinated rhizosphere environment, negatively affecting the formation of storage roots. We conducted field experiments to assess the effects of three seedling-water irrigation treatments on sweet potato root differentiation, monitoring soil water content (SWC), O₂ and CO₂ concentrations, and temperature at 0–30 cm depths, while measuring the expression of genes related to sweet potato root differentiation, shoot biomass, the number of storage roots per plant (NSRPP), and yield. The results indicated that the moderate irrigation treatment (W2) significantly increased NSRPP and yield compared to the insufficient irrigation treatment (W1) and excessive irrigation (W3). Specifically, NSRPP for W2 increased by 48.9% (2022) and 73.2% (2023) relative to W1, and by 12.7% (2022) and 14.1% (2023) compared to W3. Similarly, yield improved by 43.1% (2022) and 32.3% (2023) compared to W1, and by 11.0% (2022) and 23.8% (2023) compared to W3. Correlation analysis revealed that NSRPP is positively correlated with the expression levels of cambium-related genes (IbSRD1 and IbNAC083), while it is negatively correlated with the expression levels of xylem-related genes (IbCAD1, IbEXP1 and IbPAL1). PLS-SEM analysis indicated that soil SWC and soil CO₂ concentrations significantly influenced NSRPP, whereas temperature and soil O₂ concentrations had no significant effect. Multivariate analyses of SWC, soil CO₂ concentrations, and NSRPP revealed that the optimal amount of irrigation ranges from 112.2 to 209.5 m³ hm⁻². These conditions ensured that water, gas, and heat conditions in the rhizosphere are maintained within a range conducive to root differentiation, ensuring that a greater proportion of root differentiation events develop into storage roots. The findings of this study will provide practical guidance for water management during the rooting and branching periods of sweet potatoes.

Chickpea is an economically important legume that is susceptible to various abiotic stresses, including salinity. The intrinsic stress tolerance mechanisms in chickpea are effective under mild conditions but are compromised under severe stress. The present study evaluated the impact of 50 and 100 mM NaCl-induced salinity stress for two chickpea cultivars (PDG4 and GPF2) along with the ameliorative potential of 50 mM proline and Glycine betaine (GB) foliar spray. A comprehensive assessment was conducted encompassing growth and biomass traits, relative leaf water content, photosynthetic pigments, membrane stability, reactive oxygen species (H₂O₂, ^•O₂⁻), total protein, phenolic and flavonoid content, as well as antioxidant enzyme activities (SOD, CAT, APX). Salinity stress of 50 and 100 mM decreased the total biomass accumulation by 23.3% and 26.2% in PDG4, and 27% and 33.7% in GPF2, respectively. Foliar application of proline significantly improved the biomass by 7.6% in PDG4 and 8.7% in GPF2 under 50 mM as compared to control. Similarly, proline and GB application enhanced SOD activity by 42.7% and 27.7% in PDG4, and by 51% and 41.1% in GPF2 under 50 mM of salinity stress. CAT followed a similar trend as SOD, while APX exhibited an opposite pattern. Notably, PDG4 displayed higher resilience under both stress levels, and proline was more effective than GB in mitigating stress effects, as further supported by correlation matrices, heatmap clustering, and PCA. These findings underscore the potentiality of compatible solutes, particularly proline, in enhancing salinity tolerance in chickpea and offer promising strategies for sustainable crop management in salt-affected soils.

Maize (Zea mays L.) production and yield are threatened by water deficit in the arid and semiarid areas of China. Improving water productivity (WP_c) through innovative approaches is crucial for developing water-saving agricultural systems. Coronatine (COR) is a natural phytotoxin known to elicit plant resistance responses to biotic and abiotic stress. The aim of this study was to evaluate the effect of COR in alleviating the adverse effects of drought stress on maize growth and development. A field experiment with four treatments (I100, water applied under normal irrigation; I50, water applied under deficit irrigation; I50-0.1, 0.1 μmol L⁻¹ COR applied under deficit irrigation; I50-1.0, 1.0 μmol L⁻¹ COR applied under deficit irrigation) was implemented in the arid regions of northwest China. The results showed that deficit irrigation reduced the 2-year average yield by 10.8%. Under drought conditions, COR enhanced drought tolerance by sustaining photosynthetic efficiency, ultimately improving WP_c and yield in maize. Notably, COR application at 1.0 μmol L⁻¹ demonstrated superior efficacy in enhancing drought tolerance compared to other concentrations. The maize plants treated with 1.0 μmol L⁻¹ COR improved the 2-year average yield by 6.0% and WP_c by 17.9%, and decreased evapotranspiration by 10.0% compared to untreated control plants under deficit irrigation. These results highlight COR's potential as a water-saving agrochemical for semi-arid maize cultivation, providing a viable strategy to balance yield maintenance with limited water resources.

Drought-induced osmotic stress reduces the growth and yield of bread wheat (Triticum aestivum L.) worldwide. Several genotypes of its wild relative, goatgrass (Aegilops biuncialis Vis.) are often tolerant to environmental stresses and used as a gene source for wheat improvement. The Aegilops accessions Ae.b. 382 and Ae.b. 642 collected from contrasted agroecological habitats may represent different defence mechanisms to osmotic stress compared to three bread wheat genotypes with various drought tolerances. The effect of a 1-week 15% polyethylene glycol (PEG) treatment on various physiological and biochemical parameters was compared at the 2-leaf stage. The osmotic stress-induced reduction in shoot length and fresh weight in all genotypes except for Ae.b. 382. This tolerance of Ae.b. 382 can derive from the greater PEG-induced accumulation of the antioxidant hydroxymethyl-glutathione in the shoots compared to other genotypes. It is due to an elevated synthesis of its precursors, cysteine and gamma-glutamylcysteine. In addition, the level of oxidative stress was smaller in Aegilops biuncialis genotypes, shown by the decrease in H₂O₂ and GSSG levels in roots and shoots, respectively. The amount of gamma-glutamylcysteine was greater in their roots than in the wheat genotypes. Furthermore, PEG treatment resulted in a greater level of putrescine, as well as the expression of defence-related genes encoding Glutathione Reductase (GR), cold-regulated protein Wcor and DihydroFlavonol-4-Reductase (DFR) in the shoots of both Aegilops accessions compared to the three wheat genotypes. Based on these differences, certain Aegilops genotypes may serve as a genetic source for the improvement of the stress tolerance of bread wheat.

In order to screen out agronomic traits closely related to drought resistance of cotton, seven agronomic traits were measured, including morphological traits: plant height (PH), first vegetative shoot length of single plant (FVSL) and all vegetative shoot length of single plant (AVSL), and yield traits: boll number (BN), single boll weight (SBW), lint percentage (LP) and seed cotton yield (SCY). All agronomic traits were significantly affected by drought stress, and the morphological traits were significantly correlated, while the yield traits were opposite. Among them, the plant height and seed cotton yield were closely related to drought resistance of cotton. Comprehensive drought resistance coefficient (CDC), comprehensive drought resistance comprehensive evaluation value (D) and weighted drought resistance coefficient (WDC) value are the three comprehensive evaluation indexes of drought resistance. This study is the first to systematically validate that the D value is more scientific to reflect the differences between various agronomic traits and drought resistance of cotton than the CDC value and WDC value. Among the 199 cotton genotypes, there were large differences in drought resistance, and by using cluster analysis, they were divided into five groups: high drought resistance, drought resistance, medium drought resistance, drought-sensitive and high drought sensitivity groups. Four cotton genotypes with high drought resistance were selected; UC072 and UC002 can be widely used as drought resistant genotypes with high yield.

Root system architecture (RSA) is crucial to plant adaptation and the efficiency of soil resource acquisition. However, the RSA variation in okra remains fundamentally uncharacterised. This study aimed to fill this knowledge gap by investigating genetic variability, heritability, and trait associations of RSA characteristics across sixty okra genotypes using a rhizobox-based phenotyping system that evaluated over 30 RSA traits. There was genotypic variation with coefficients of variation ranging from 5% to 70%. Most traits (76%) demonstrated high broad-sense heritability (> 60%), particularly those important for capturing soil resources, including total root length, surface area, and volume. Genetic and phenotypic coefficients of variation were predominantly intermediate (10%–20%) to high (> 20%), except for lateral root angle and primary root length, which showed low variation (< 10%). The first four principal components explained 81.7% of the total genotypic variation, with root perimeter, surface area, and volume as the primary contributors to the diversity in the RSA. There were two genotype groups with contrasting RSA ideotypes independent of the geographical origin of the germplasm. There were moderate to very strong, significant positive associations among many RSA and biomass traits (r = 0.51–0.99; p < 0.001). However, the mean root diameter exhibited weak negative but non-significant correlations with several characteristics. Notable genotypes were identified for specific RSA traits: VI063895 (0.39 and 0.40 g), VI060692 (0.32 and 0.33 g), and GH154 (0.30 and 0.34 g) for superior root biomass allocation; GH108 (2032.28 and 1895.14 cm) for maximum root length; GH111 (25.14 and 20.80 cm³), GH121 (23.56 and 24.59 cm³), and GH157 (18.54 and 19.06 cm³) for enhanced root volume; VI060691 (60° and 62°) and GH125 (61° and 59°) for steep lateral root angles; and V1063895 (10,899 and 10,873), GH135 (9464 and 9330) and GH102 (9303 and 9441) for branching architecture across the two trials. This study advances our understanding of okra RSA diversity, laying the groundwork for trait-based breeding strategies that enhance adaptation to resource-limited environments. The identified genotypes represent diverse RSA ideotypes that offer the potential for improving nutrient and water use efficiency.