Journal of Agronomy and Crop Science最新文献

Drought stress significantly challenges wheat production globally, and drought priming has emerged as an effective strategy to mitigate yield loss under drought stress events. However, the effect of drought priming on plant nitrogen use efficiency (NUE) remains insufficiently understood. This study investigates the effects of drought priming at the six-leaf stage on NUE under drought stress during grain filling in four wheat varieties with distinct responses to drought priming. Our results indicate that there is no correlation between inherent drought tolerance and the effects of drought priming among the wheat varieties studied. In priming-sensitive varieties, drought-primed plants exhibited significant improvements in grain yield and NUE under drought stress compared to non-primed plants. Conversely, priming-insensitive varieties showed no significant differences in yield or NUE between primed and non-primed plants under similar conditions. Notably, under drought stress, primed plants exhibited higher yield and NUE than non-primed plants in drought priming positive variety, while the opposite trend was observed in drought priming negative response variety. The enhancement of NUE through drought priming was associated with improved nitrogen uptake efficiency and its allocation to spikes, with abscisic acid accumulation playing a pivotal role. These findings provide valuable insights into the mechanisms by which drought priming enhances NUE under drought stress, contributing to the development of sustainable agricultural practices amid climate change.

High temperature during early grain-filling stage is one of the serious abiotic stresses limiting maize yield in the North China Plain. Nitrogen (N) fertiliser has an important role in promoting crop growth, especially under abiotic stresses. However, its contribution to alleviating heat stress (HS) inhibition on maize photosynthesis during early grain-filling stage is still unclear. Experiments with three N rates (LN, low nitrogen; MN, medium nitrogen; HN, high nitrogen) and two temperature (HS, heat stress; CK, ambient temperature as control) regimes were conducted to examine the effects of increasing N supply on photosynthesis, N assimilation, antioxidant system, and hormones homeostasis of maize during early grain-filling stage using two maize hybrids Xianyu335 (XY335, heat-sensitive) and Zhengdan (ZD958, heat-tolerant). HS negatively affected photosynthesis of both two hybrids, exhibited lower net photosynthetic rate, chlorophyll content and activities of Rubisco and phosphoenolpyruvate carboxylase (PEPC) compared with CK, and then decreased dry matter accumulation of maize, with a lesser extent for ZD958 than XY335. However, increasing N supply alleviated the adverse effects of HS on maize photosynthesis due to improved N assimilation capacity. Under HS condition, greater N content and higher activities of glutamine synthetase and glutamate synthase in maize ear leaf were found in treatment of HN compared with LN and MN. HN with higher N assimilation capacity directly increased the net photosynthetic rate due to improved chlorophyll content, activities of Rubisco and PEPC and antioxidant capacity. HS-induced abscisic acid (ABA) accumulation was also repressed by HN, and then enhanced the stomatal conductance and transpiration rate to maintain higher photosynthetic capacity compared with LN and MN. Moreover, the positive effects of increasing N supply on maize photosynthesis under HS condition exhibited a larger extent for XY335 than ZD958. As a result of improved photosynthesis and N assimilation capacity by adequate N supply, maize accumulated more biomass under HS, especially for heat-sensitive hybrid.

Due to increasingly serious soil salinisation, exploring high-quality closely related wild species is an effective means to solve food security problems. In this study, based on comprehensive metabolomics and transcriptomics analyses of the types, quantities, metabolic pathways and gene expression of small molecule metabolites in cotyledons and embryo axis/root, we report the strategies used by barren-tolerant wild soybean (GS2) to resist salt stress during the post-germination period. Our results showed that salt tolerance in GS2 cotyledons mainly involves the enhanced mobilisation of reserves, including lipid and sugar breakdown and utilisation, as well as protein breakdown and, in particular, the transport of amino acids to the embryo axis/root. Moreover, antioxidant capacity is enhanced through the promotion of ascorbic acid and naringin synthesis. We also found that under salt stress, the GS2 embryo axis/root accumulates proline by promoting the ornithine biosynthetic pathway, while stimulating glutathione metabolism to eliminate excess reactive oxygen species and restore oxidative balance. In addition, to establish and elongate the embryo axis/root, lignin synthesis is enhanced by the promotion of the shikimic acid pathway, which compensates for the decrease in cell wall support caused by salt stress. This study lays the foundation for developing and utilising high-quality wild plant resources.

The increase in crop yield can be primarily attributed to the combined effect of genetic advancements, as well as increased contributions from nitrogen (N) and water. The accumulation of dry matter plays a crucial role in determining grain yield in winter wheat. The current study aimed to better understand the source-sink dynamics, analyse the dry matter transport (DMT) before and after anthesis and calculate its ratio to grain yield. In this experiment, eight main cultivars of winter wheat that have been widely cultivated in Shaanxi Province since the 1940s were selected as planting material. Field examinations were conducted using three levels of both irrigation and N. The yield-related parameters, dry matter accumulation, dry matter distribution, DMT and DMT efficiency were measured. The results showed that irrigation prolonged the time of dry matter accumulation, and the application of N fertiliser increased the rate of dry matter accumulation. The analysis of the dynamic characteristic parameters of dry matter in winter wheat showed that irrigation and N had a significant impact on rate of dry matter accumulation. The proportion of stems, leaves and spikes of new varieties increased significantly (p < 0.05), which increased by 56.67%–69.7%, 13.26%–18.07% and 15.78%–28.26%, respectively, with the varietal improvement. The DMT efficiency increased with varietal improvement and also with increased irrigation and N application. The response of irrigation treatment to DMT and dry matter was more significant. In addition, the irrigation treatment had a higher effect on the DMT efficiency of vegetative organs after anthesis. The logistic equation analysis revealed that water stress accelerated the fulfilment of maximum daily temperature (T_max), while both the maximum growth rate (G_max) and dry matter weight (W_max) decreased as water stress increased. There was a positive linear relationship between dry matter accumulation after anthesis and grain yield. The structural equation model showed that varieties, N application and irrigation had significant positive effects on DMT, post-anthesis dry matter and grain yield, while irrigation had significant negative effects on DMT efficiency. The accumulation of dry matter in winter wheat after anthesis showed a significant increase with the succession of varieties. The combination of moderate deficit irrigation and fertilisation improved transportation and dry matter accumulation after anthesis in winter wheat, thereby enhancing its production capacity.

Sugar beet (Beta vulgaris L.) is a globally significant crop, valued for its economic importance in sugar production. Saline-sodic soil environments negatively impact sugar beet productivity. This study investigates the effects of using compost, glauconite enriched-K and their combinations in mitigating the saline-sodic soil environment, sugar beet productivity and extracted sugar quality. A two-season field experiment in split-plot design with the main plots is three doses of compost: control (C0), recommended (100%) dose (C1) and 150% recommended dose (C2). Each group divided into four subplots of glauconite treatments arranged according to the recommended dose of potassium (K) as follows: G0 (no glauconite), G1 (50% K), G2 (100% K, 480 Kg glauconite Fed⁻¹) and G3 (150% K). The results showed that compost and glauconite mitigated adverse soil effects caused by salinity and sodicity. The C2G3 treatment reduced electrical conductivity (EC) and exchangeable sodium percentage (ESP), improved organic matter and enhanced soil bulk density, porosity and penetration resistance. This combination also increased soil nutrients (N, K, Fe, Mn, Zn and Cu). Regarding the sugar beet yield, C2G3 improved root yield, top yield, sugar yield and extracted sugar. The application of glauconite increased root diameter by 20% and root length by 23%, enhanced sugar quality with minimal sugar losses to molasses (2.43%), and reduced impurities of K, α-amino N and Na. Principal component analysis showed positive correlations between root yield and soil potassium, organic matter, cation exchange capacity and soil porosity, with negative correlations to bulk density, EC, pH and ESP. Two-way analysis of main (ANOM) illustrated significant effects of compost and glauconite on soil–plant interactions. Multivariate analysis indicated that higher glauconite doses significantly enhanced root yield. The Gag run charts confirmed that compost (100%) and G3 levels explored more homogeneity reducing the ESP%, increasing sugar beet root yield, sugar yield and quality.

Identifying the genomic regions (quantitative trait loci (QTL)) significantly linked to grain yield under drought stress could expedite the development of novel rice cultivars suited for rainfed areas through marker-assisted breeding. This study identified QTL regions linked to plant phenology and production traits by evaluating 122 recombinant inbred lines (RILs) of Danteshwari × Daggaddeshi under different environmental conditions. A consistent QTL region associated with grain yield under water stress (60.4 Mbp) was mapped on chromosome 1 between RM428 and RM24 with an LOD score of 4.0. Another QTL region (9.4 Mbp) linked to plant height under all environmental conditions was mapped on chromosome 1 between RM1-HvSSR1-87 with a LOD score of 7.5 and phenotypic variance of 25%. A core set of 402 diverse rice accessions was also evaluated under water stress conditions and subjected to genome-wide association analysis. Twelve markers linked to grain yield under drought were identified, out of which five were significantly associated with grain yield and days to flowering under drought. The markers linked to grain yield were compared between the bi-parental population and germplasm accessions to identify the common markers. Three markers (RM1, RM259 and RM201) were found to be consistently linked to drought stress across the seasons in both bi-parental population and germplasm accessions studied and could be potential candidates for application in marker-assisted selection for improving grain yield under drought stress in rice.

Warm night frequency has increased steadily in the last years across maize production regions, but high night temperature (HNT) effects on growth, grain yield and maize dry matter allocation (DMA) to different plant organs remain poorly understood. In this study, we aimed to (i) analyse the DMA among reproductive and vegetative organs, (ii) evaluate the individual kernel weight through its determinants, rate and duration of grain filling and (iii) quantify changes in grain yield per plant and its components due to HNT during the postflowering and early grain-filling period. Field-grown maize was subjected to HNT induced by shelters during a 15- or 30-day period after silking, encompassing the postflowering period (HNT₁₅) and extending the heating into early grain filling (HNT₃₀), respectively. The HNT was applied from 1900 to 0700 h while control plots remained at ambient night temperature (ANT). Kernel number per plant was decreased under both temperature regimes (i.e., HNT₁₅ and HNT₃₀); however, significant reductions in grain yield were only observed under HNT₃₀. The DMA during the heating period was differentially affected by the duration of heating. While DMA to the stem was likewise reduced by both heating treatments, the partition to the uppermost ear was only reduced under HNT₃₀. Related to the lack of response to HNT treatments of the rate and duration of grain filling, the individual kernel weight was not reduced. The source-sink ratio was not affected by HNT, meanwhile, the apparent reserve use was significantly reduced under HNT₃₀. Our results demonstrate that the magnitude of HNT effects is subjected to the duration of the heating period, but also depends on the intensity of heating explored across seasons, especially for kernel number and grain yield.

The escalating population growth has spurred a demand for increased oilseed production, necessitating urgent attention. However, the expansion of saline-affected regions posed a significant obstacle to maintain peanut productivity in these areas. Thus, to tackle the productivity decline in saline-affected regions, we investigated whether substituting polythene mulch with straw mulch, as part of an agronomic management strategy, could mitigate the rapid decrease in peanut productivity. Three mulching methods (control, polythene mulch and straw mulch) were employed to cultivate the crop (cv. TG 37A) under salinity levels of 0.5, 2, 4 and 6 dS m⁻¹. As salinity levels increased, there was a notable decrease in germination percentage, growth, yield and biochemical characteristics, including pod and haulm yields were reported. Despite salinity reduced free amino acids and oil content, it exhibited significant increase in protein and sugar content. Saline irrigation water led to a reduction in pod yield, haulm yield and oil content by 24.67%, 23.84% and 5.07%, respectively, at a salinity level of 6.0 dS m⁻¹ compared to the control with 0.5 dS m⁻¹ salinity. Moreover, straw mulching resulted in a boost in pod yield, haulm yield and oil content by 30.09%, 4.83% and 1.75%, respectively, compared to the control. The reduction in pod yield and oil content under the interaction of mulching and salinity was 46.44% and 6.87% at M₀S₆, 21.42% and 4.44% at M₁S₆, and 7.55% and 3.87% at M₂S₆ compared to M₀S₀, M₁S₀ and M₂S₀, respectively. A similar trend was also observed in 100-pod weight, 100-kernel weight and shelling percentage. Accordingly, it was concluded that the declining trend in all attributes under straw mulching at various salinity levels surpassed polythene mulching, ensuring superior peanut production under salinity stress conditions.