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Rice cultivation in Madurai district, Tamil Nadu, spans distinct cropping seasons: Kar (May -- Jun), Semi-dry (Jul - Aug), Samba/ Late Samba (Aug - Sep), and Navarai (Dec - Jan), each with unique weather conditions and rice varieties. This study explores the correlation between weather parameters temperature, rainfall, humidity, sunshine hours, and wind speed and rice blast disease severity from 2021 to 2023. Using multiple linear regression with ordinary least squares (OLS), the analysis achieves high predictive accuracy (R² = 0.98). Results show that the maximum temperatures correlated negatively with disease severity (r = -0.869 to -0.892), while rainfall (r = 0.768 to 0.804) and wind speed (r = 0.766 to 0.938) correlated positively during the semi-dry season. Relative humidity exhibits varying impacts across seasons. These findings underscore the importance of tailored disease management strategies, such as targeted fungicidal applications during warmer seasons and optimized water management in others. By elucidating these dynamics, the study enhances understanding of weather-disease interactions, providing actionable insights to optimize disease management and enhance crop resilience in Madurai district. [ABSTRACT FROM AUTHOR]

Background: Grazing lands provide numerous ecosystem services, including the capacity to store large amounts of soil carbon (C); however, our understanding of the factors affecting soil C responses to management is inadequate. Methods: In this paper, we synthesized information about the impacts of grazing land management on soil C within the southeastern region of the United States. Results: Most studies (68%) demonstrated that proper management increased soil C stocks with an average C accumulation rate of 1.4 Mg C ha−1 year−1. The remaining (32%) studies showed no effect of management on soil C. None of the studies reported negative impacts of management on soil C. The largest increase in soil C (8 Mg C ha−1 year−1) was associated with the conversion of cropland to pastureland while overseeding legumes into grass pastures resulted in the lowest C sequestration rates (0.2 Mg C ha−1 year−1). Conclusions: Considering the rates of soil C accretion and the extensive area occupied by grazing lands, data in this synthesis confirm that the adoption of improved management practices can increase soil C sequestration in the southeastern United States. In addition, because most improved management practices can also have co‐benefits, they may be favorable for forage and livestock production and other ecosystem services. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) is one of the major cereal staple food crops consumed by more than 50 per cent of the world's population. Due to global climatic changes, the crop has to withstand higher temperatures in the near future. In India, rice cultivation is more affected by climate change and it contributes to yield loss and in severe cases results in crop failure both of which leads to economic losses. Grain yield declined by 10% for each 1°C increase in minimum temperature in the dry season whereas the effect of maximum temperature was insignificant. Significant variation exists among rice germplasm in response to high temperature stress. Producing an economically significant yield under heat stress conditions depends on floral biology of rice and several plant physiological parameters and mechanisms that contribute to heat tolerance in the field, such as photosynthesis, chlorophyll content, canopy temperature depression and concomitant increases of transcripts coding for proteins involved in protection. According to the objectives of this study, the literature pertaining to the aspects of heat tolerance and effect of high temperature on floral biology and physiological parameters in rice is briefly reviewed. [ABSTRACT FROM AUTHOR]

Micrometeorological monitoring is not just an effective method of determining the impact of heat stress on rice, but also a reliable way of understanding how to screen for heat tolerance in rice. The aim of this study was to use micrometeorological monitoring to determine varietal differences in rice plants grown under two weather scenarios--Long-term Heat Scenario (LHS) and Normal Weather Scenario (NWS)-- so as to establish reliable methods for heat tolerance screening. Experiments were conducted with two heat susceptible varieties --Mianhui 101 and IR64--and two heat tolerant varieties, Quanliangyou 681 and SDWG005. We used staggered sowing method to ensure that all varieties flower at the same time. Our results showed that heat tolerant varieties maintained lower canopy temperature compared to heat susceptible varieties, not just during the crucial flowering period of 10 am to 12 pm, but throughout the entire day and night. The higher stomatal conductance rate observed in heat tolerant varieties possibly decreased their canopy temperatures through the process of evaporative cooling during transpiration. Conversely, we found that panicle temperature cannot be used to screen for heat tolerance at night, as we observed no significant difference in the panicle temperature of heat tolerant and heat susceptible varieties at night. However, we also reported that higher panicle temperature in heat susceptible varieties decreased spikelet fertility rate, while low panicle temperature in heat tolerant varieties increased spikelet fertility rate. In conclusion, the results of this study showed that canopy temperature is probably the most reliable trait to screen for heat tolerance in rice. [ABSTRACT FROM AUTHOR]

Considerable variation among soybean genotypes has been observed in growth and yield adaptations to tropical environments. However, the response to daylength and, hence, different growth durations are confounding factors in most studies. In this study, we conducted field experiments in a tropical environment with daylength treatment to compare the crop performance of temperate and tropical cultivars with different daylength sensitivities in terms of biomass production, seed yield, and apparent seed quality. A tropical cultivar, 'Tanggamus', which has been highly productive in Indonesia, was grown for two years in a field at Bogor, Indonesia (lat. 6.5° S) with four cultivars from temperate regions. The proposed long-day treatment (LD) decreased the negative effects of short daylength in low-altitude areas on the vegetative growth and yield of soybean cultivars from temperate regions. With LD, the differences in the yield and above ground dry weight between temperate cultivars and 'Tanggamus' was less than without LD. However, the ratio of wrinkled seeds of temperate cultivars with LD was higher than that of 'Tanggamus'. There were differences in the seed-filling rate and the growth rate of pod plus seed during latter half of the seed-filling period between them, indicating a higher ability in the supply of assimilates to seeds under high-temperature conditions during the seed-filling stage. These results suggest that temperate cultivars remain to be improved in biomass and seed production under environments with higher temperatures than the climate where they are cultivated, and that 'Tanggamus' will be worth utilizing in breeding programs. [ABSTRACT FROM AUTHOR]

The significance of heat stress in agriculture is ever-increasing with the progress of global climate changes. Due to a negative effect on the yield of staple crops, including wheat, the impairment of plant reproductive development triggered by high ambient temperature became a restraint in food production. Although the heat sensitivity of male meiosis and the following gamete development in wheat has long been recognized, a detailed structural characterization combined with a comprehensive gene expression analysis has not been done about this phenomenon. We demonstrate here that heat stress severely alters the cytoskeletal configuration, triggers the failure of meiotic division in wheat. Moreover, it changes the expression of genes related to gamete development in male meiocytes and the tapetum layer in a genotype-dependent manner. 'Ellvis', a heat-tolerant winter wheat cultivar, showed high spikelet fertility rate and only scarce structural aberrations upon exposure to high temperature. In addition, heat shock genes and genes involved in scavenging reactive oxygen species were significantly upregulated in 'Ellvis', and the expression of meiosisspecific and major developmental genes showed high stability in this cultivar. In the heat-sensitive 'Mv 17-09', however, genes participating in cytoskeletal fiber nucleation, the spindle assembly checkpoint genes, and tapetum-specific developmental regulators were downregulated. These alterations may be related to the decreased cytoskeleton content, frequent micronuclei formation, and the erroneous persistence of the tapetum layer observed in the sensitive genotype. Our results suggest that understanding the heat-sensitive regulation of these gene functions would be an essential contribution to the development of new, heat-tolerant cultivars. [ABSTRACT FROM AUTHOR]

Ants and other insects are often a source of localized secondary dispersal for wind-dispersed plants and thus play an important ecological role in their spatial dynamics, but there is limited information on how climate change will affect such dispersal processes. Here, we use field experiments to investigate how climate warming affects seed removal, as this initiation of movement represents the first step in insect-driven secondary dispersal. Our results indicate that for the invasive thistles Carduus nutans and Carduus acanthoides, increased growing temperature influences seed attractiveness to insect dispersers, with seeds from maternal plants grown at temperatures 0.6°C above ambient removed by insect dispersers at higher rates than their unwarmed counterparts. We also observe that seed elaiosomes in these two species play an important role in dispersal, as seeds without elaiosomes were significantly less likely to be removed over the same period. Significant interactions between elaiosome presence/absence and warming treatment were also observed, though only for C. acanthoides, with the boost in seed removal from warming dampened when the elaiosome was present compared to when it was absent. These findings provide evidence that climate warming may alter aspects of dispersal such as seed removal by secondary dispersers, with potential ramifications for dispersal in future climates since seed-bearing plants around the world may be subject to increased growing temperatures, and many of these plant species bear elaiosomes and experience seed dispersal by insects., (© 2023 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)