Journal of Agronomy and Crop Science最新文献

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.

Nighttime warming decreased single rice production in southern China, while silicate supply increased the yield and stress resistance. It is still unclear regarding the impacts of silicate application on the growth, yield and quality in rice under nighttime warming. A field experiment was conducted to investigate the impacts of silicate application on the growth, yield and quality during rice growing period under nighttime warming. The warming was set at two levels, that is, ambient temperature (CK) and nighttime warming (NW). The open passive nighttime warming was used in this study, that is, rice canopy was covered with aluminium foil reflective film at night (19:00–6:00). Silicate fertiliser (steel slag) was applied at two levels, that is, Si₀ (0 kg SiO₂·hm⁻²) and Si₁ (200 kg SiO₂·hm⁻²). The results indicated that, compared with the control, the average nighttime temperature on rice canopy and at 5 cm soil layer increased by 0.51°C–0.59°C and 0.28°C–0.41°C during the rice growing period, respectively. Under nighttime warming, silicate supply increased the dry weight of shoot, total dry weight of the whole plant and yield by 64.1%, 55.3% and 7.1% at the filling-maturity stage, respectively. Silicate application significantly reduced dry matter translocation rate with 15%–18%, but significantly increased the root-shoot ratio with 0.39–0.41 in rice. Under nighttime warming, silicate supply significantly increased milled rice rate, head rice rate and total starch content by 2.3%, 2.5% and 41.8%, respectively. Nighttime warming reduced the yield by decreasing the number of effective panicle, seed setting rate and 1000-grain weight, but increasing empty chaff grain. Silicate supply increased the yield by increasing the number of effective panicle, filled grains per panicle, seed setting rate and 1000-grain weight, but reducing empty chaff grain. This study suggests that silicate supply can effectively alleviate the suppressive effects of nighttime warming on single rice growth, yield and quality in Southern China.

Changes in precipitation and snow melt during warmer winters can increase low-temperature waterlogging. Such conditions may bring about different effects when compared with a single stress trigger, such as low-temperature or water excess. The effects of waterlogging are clearly related to water temperature, and the consequences of water excess might be less severe, as more oxygen is dissolved in colder water. The effect of waterlogging during cold acclimation (CA) is poorly understood; most experiments concerning water excess are performed at relatively high-temperatures. In this study, we examined the effect of 3 weeks of waterlogging (approx. 2 cm above the soil level) on CA in Festuca pratensis Huds. (Fp), a cool-season grass. Measurements were taken before CA (after prehardening, before flooding) and after 3 weeks of CA in waterlogged (treated) and non-waterlogged (control) plants. The work included: (i) freezing tolerance test (regrowth after freezing), (ii) analysis of abscisic acid (ABA) content in the leaf, (iii) leaf stomatal conductance, (iv) leaf water content, (v) carbohydrates analysis, including fructans, and (vi) transcript levels of selected genes involved in freezing tolerance, ABA signalling and fructan biosynthesis. The aim of the study was to test a hypothesis that low-temperature waterlogging in Fp enhances freezing tolerance (plant regrowth after freezing) related to increased ABA accumulation, increased C-repeat-binding transcription factor expression and/or increased carbohydrate accumulation, including fructans. Two out of four genotypes exhibited enhanced regrowth following freezing due to waterlogging relative to control. Principal component analysis (PCA) revealed a positive correlation between ABA levels and freezing tolerance in both treatments, with a more pronounced effect observed in the waterlogged plants. However, the phytohormone played different roles in these two treatments. In the context of low-temperature waterlogging, ABA may be involved in the dehydration tolerance response in genotypes suffering from physiological drought, as well as the induction of C-repeat-binding transcription factors (CBFs) and sucrose, which may improve freezing tolerance. The increased fructan amount and polymerisation degree due to waterlogging may provide a carbohydrate sink to maintain a high photosynthetic efficiency, but are not directly responsible for freezing tolerance changes. The study indicates that tolerance mechanisms of Fp exposed to low-temperature waterlogging involve maintaining a high photosynthetic rate, as well as oxidative and dehydration stress tolerance.

In many parts of the world, solar radiation has decreased during the past 50 years due to industrialisation-induced elevations in air aerosols which has negatively impacted crop productivity. Climate change threatens rapeseed (Brassica napus L.) production due to shade stress caused by reduced light radiation. However, studies on how shade affects photosynthetic mechanisms in rapeseed (leaves and pod wall) are not well documented. Understanding the mechanisms of shade on yield formation in rapeseed is important for breeding shade-tolerant rapeseed varieties and optimising agricultural management practices in low-light areas. Therefore, this study assesses the impacts of ‘global dimming’ simulated by shading at a specific period on rapeseed's photosynthetic behaviour, yield and seed quality. A two-factor split-plot design was arranged with three shading treatments (CK, FS and PS) and two hybrid genotypes (Chuannong and Zhongyouza) of rapeseed. We observed that shading at the flowering stage (FS) significantly inhibited the leaf area index, chlorophyll content, photosynthetic efficiency and enzymatic activities of both genotypes. Besides that, shading at pod development stage (PS) substantially declined the pod photosynthetic characteristics and transportation of carbohydrates towards economic organ (seeds) which directly decreased the yield of rapeseed. We found that PS treatment remarkably declined the oil content of both genotypes. According to the results, the photosynthetic capacity of rapeseed pod wall had a greater impact on yield and seed quality than leaves. Therefore, improving the photosynthetic capacity and material transport efficiency of the pod wall is a potential measure to increase the yield of rapeseed under shade stress. This study provides a new insight into the effects of shade on rapeseed production and provides a valuable reference for rapeseed breeding techniques to develop high-yielding genotypes by enhancing the photosynthetic efficiency of rapeseed pod wall in low-light conditions.

Water deficit priming through regulated deficit irrigation has been shown to be beneficial for peanut cultivation, leading to improved water-use efficiency during the crop cycle and enhanced stress acclimation. The effects of priming using water deficit can be heritable, but little is known about stress priming effects on the physiology and growth of successive generations undergoing water stress. Two experiments were conducted to assess cross-generational priming by determining physiological and growth responses of offspring of primed and non-primed peanut plants of two genotypes, COC-041 and New Mexico Valencia C (NMV-C), both previously found to be strongly responsive to priming. Seeds were collected from parental plants subjected to mild water stress by regulated deficit irrigation (primed) or adequate irrigation (non-primed). These seeds were then planted, and the offspring were monitored for physiological and growth responses to water stress, including on a whole-plant basis using a high-throughput physiological phenotyping platform and on individual leaves by periodic single-leaf measurements. Measurements included whole-plant transpiration (plant-Tr), root water uptake, leaf transpiration, stomatal conductance and net CO₂ assimilation (leaf-Tr, leaf-g_s, and leaf-A), leaf water and osmotic potential (leaf-Ψ_w and leaf-Ψ_o), leaf osmotic adjustment, leaf relative water content (leaf-RWC) and cumulative plant-Tr. Offspring of both genotypes from primed parent plants had faster early establishment, with more uniform germination, and more rapid initial seedling growth compared to offspring from non-primed parent plants. Although offspring of both non-primed and primed plants of both genotypes exhibited a significant reduction of plant-Tr, gas exchange, leaf-Ψ_w, leaf-Ψ_o, and leaf-RWC when exposed to water stress, offspring of primed plants showed increased water use efficiency through reduced leaf-g_s, leaf-Tr and plant-Tr while maintaining leaf-A under water stress. Despite offspring of both primed and non-primed plants being susceptible to severe water stress, offspring of primed plants exhibited overall enhanced water use efficiency, leading to greater dry biomass production per gram of transpired water and a trend of less growth reduction due to water stress compared to offspring of non-primed plants, especially for the genotype COC-041. This study shows the potential of water deficit priming to promote cross-generational changes in physiological function under limited water availability, by enhancing crop stress acclimation in the next plant generation.

Drought is one of the most adverse factors affecting plant growth and productivity. Identifying elite genotypes and their ideotypic traits conferring high yield potential and drought tolerance is critical in selecting and breeding drought-tolerant wheat cultivars. In this study, we conducted field experiments at the Xinxiang Agricultural Comprehensive Experimental station in the North China Plain from 2018 to 2020 and assessed 209 wheat cultivars released since the 1940s under irrigated and nonirrigated conditions. Then, we selected drought-tolerant cultivars by classifying them into four groups based on yield response to drought stress and several drought indices. Finally, the key ideotypic traits associated with high yield potential and drought tolerance were identified. Results indicated that the grain yield of the 209 cultivars decreased on average by 10.4% and 9.4% under nonirrigated treatment in 2018–2019 and 2019–2020, respectively, relative to full irrigation. The high-yielding cultivars under both irrigation treatments are characterised by a compact plant type, larger thousand-grain weight, larger chlorophyll content, higher leaf photosynthesis, shorter plant height and stay-green traits. The stomatal and nonstomatal limitations are strongly associated with genotype yield performance, elucidating a potential mechanism underlying drought tolerance. Drought tolerance and yield stability of wheat cultivars have been improved through breeding over the past 70 years. Our findings enhance understanding of drought tolerance and identify genotypes and traits beneficial for breeding high-yielding and drought-tolerant cultivars.

Freeze tolerance is a complex agronomic trait that is difficult to evaluate in the field because of year-to-year variation in weather. Discovering plant characteristics closely related to freeze tolerance would enable more effective selection for this important trait. To explore possible physiological mechanisms and search for useful characteristics related to freeze tolerance in winter barley, we conducted field and growth chamber experiments with seven freeze-tolerant and seven freeze-susceptible genotypes that exhibited contrasting winter survival in preliminary field screenings. In a 2-year field experiment, malondialdehyde, proline and water-soluble carbohydrate concentrations were measured during cold acclimation and deacclimation to investigate differences in osmoregulation and membrane stability between freeze-tolerant and freeze-sensitive genotypes. All parameters varied by sampling year, and significant differences between freeze tolerance groups were found mainly during cold deacclimation in the spring. In growth chamber experiments, the size of xylem vessels and stomates was measured with and without cold acclimation. Freeze-tolerant genotypes had smaller xylem vessels and stomates than freeze-sensitive genotypes with and without cold acclimation, and small stomatal length was associated with a small xylem vessel area. Thus, it may be possible to improve freeze tolerance in winter barley by selecting smaller xylem and stomate cells. This study also validated germplasms of winter barley with differential freeze tolerance for future projects on breeding for improving winter hardiness and on plant physiology and genetics in response to freezing stress.

Global warming has led to more frequent extreme weather events, such as heavy summer rains, in the Huang-Huai-Hai region. These events significantly impede the growth and development of waxy maize in the area and disrupt the stable progression of the industry. However, there is a lack of effective agricultural measures to mitigate the impact of waterlogging, and the underlying regulation mechanisms remain unclear. To fill this knowledge gap, we conducted a two-year experiment to assess whether exogenous EDAH (a mixture of ethephon and diethyl aminoethyl hexanoate (DA-6), ethephon: DA-6 = 27%: 3%) application during the waxy maize V6 stage, combined with 10 days of waterlogging treatment at the V6, VT and R2 growth stages. The results indicate that exogenous EDAH mitigates the adverse effects of waterlogging stress to a certain extent. It is noteworthy that exogenous EDAH increases the leaf area index and photosynthetic parameters of waxy maize, enhances the activity of catalase in ear leaves at the R3 stage, inhibits the accumulation of malondialdehyde and delays premature aging of plants. Furthermore, exogenous EDAH delays premature ripening of grains caused by waterlogging, increases the moisture content of fresh waxy maize grains during the fresh edible period, but does not effectively mitigate the yield losses caused by waterlogging. However, exogenous EDAH effectively improves grain quality under waterlogging stress, increasing the soluble sugar content and total protein content while reducing starch content, ultimately enhancing the edibility of fresh ears. Through TOPSIS comprehensive evaluation, it can be inferred that exogenous EDAH effectively mitigates the overall impact of waterlogging on waxy maize at both the V6 and VT stages. This research sheds light on potential strategies to mitigate the adverse effects of waterlogging on agricultural productivity and grain quality.