Santanu K. Bal

Temperature Impacts the Development and Survival of Common Cutworm (Spodoptera litura): Simulation and Visualization of Potential Population Growth in India under Warmer Temperatures through Life Cycle Modelling and Spatial Mapping

The common cutworm, Spodoptera litura, has become a major pest of soybean (Glycine max) throughout its Indian range. With a changing climate, there is the potential for this insect to become an increasingly severe pest in certain regions due to increased habitat suitability. To examine this possibility, we developed temperature-based phenology model for S. litura, by constructing thermal reaction norms for cohorts of single life stages, at both constant and fluctuating temperatures within the ecologically relevant range (15–38°C) for its development. Life table parameters were estimated stochastically using cohort updating and rate summation approach. The model was implemented in the geographic information system to examine the potential future pest status of S. litura using temperature change projections from SRES A1B climate change scenario for the year 2050. The changes were visualized by means of three spatial indices demonstrating the risks for establishment, number of generations per year and pest abundance according to the temperature conditions. The results revealed that the development rate as a function of temperature increased linearly for all the immature stages of S. litura until approximately 34–36°C, after which it became non-linear. The extreme temperature of 38°C was found lethal to larval and pupal stages of S. litura wherein no development to the next stage occurred. Females could lay no eggs at the extreme low (15°C) and high (> 35°C) test temperatures, demonstrating the importance of optimum temperature in determining the suitability of climate for the mating and reproduction in S. litura. The risk mapping predicts that due to temperature increase under future climate change, much of the soybean areas in Indian states like Madhya Pradesh, Maharashtra and Rajasthan, will become suitable for S. litura establishment and increased pest activity, indicating the expansion of the suitable and favourable areas over time. This has serious implication in terms of soybean production since these areas produce approximately 95% of the total soybeans in India. As the present model results are based on temperature only, and the effects of other abiotic and biotic factors determining the pest population dynamics were excluded, it presents only the potential population growth parameters for S. litura. However, if combined with the field observations, the model results could certainly contribute to gaining insight into the field dynamics of S. litura.

Identification of SNP in HSP90AB1 and its Association with the Relative Thermotolerance and Milk Production Traits in Indian Dairy Cattle

Heat shock proteins (Hsp) play crucial role in cellular thermotolerance and heat stress response. In the present work, Allele specific PCR (AS-PCR) was standardized to detect the nucleotide polymorphism within the HSP90AB1 gene (SNP g.4338T>C) in Indian breeds of dairy cattle. The identified genotypes were associated with relative thermotolerance in terms of physiological parameters and milk production traits. The results of the experiments revealed that the genotype frequency of CC, CT, and TT for Sahiwal were 0.05, 0.78, and 0.17, respectively, and in Frieswal, the frequencies were 0.20, 0.70, and 0.10, respectively. The average rectal temperature (ART) and average respiration rates (ARR) were recorded during peak summer stress and heat tolerance coefficient (HTC) was calculated. The association studies indicated that TT genotypes had significantly (P < 0.01) higher HTC and lower ARR values than CT and CC in both the breeds. The TT genotype animals also had better production parameter in terms of total milk yield (TMY) (P < 0.01). These findings may partly suggest the role of HSP90AB1 polymorphisms in the regulation of heat stress response and consequent effect on production traits. Nevertheless, involvement of other regulatory mechanisms cannot be overruled.

Performance of direct-seeded rice under various dates of sowing and irrigation regimes in semi-arid region of India

Abstract Rice (Oryza sativa L.) is the most important staple food crop in the southern region of Asia, and Indian subcontinent being one of the major producers. Production of conventional transplanted rice requires a large amount of irrigation water, labor, and energy. The scarcity of irrigation water has encouraged farmers to adopt an alternative rice production system, i.e. the direct-seeded rice (DSR), which is proposed to be farmers’ friendly with a potential to save water. Our study reports the performance of DSR with respect to yield and water expense efficiency based on different irrigation regimes and dates of sowing. A field experiment was conducted in the semi-arid region of northern India during the rainy season of 2011 with two treatment combinations (dates of sowing: 15th May and 5th June and three irrigation regimes: irrigation scheduled at irrigation water-to-cumulative potential evapotranspiration; IW/CPE ratio of 1.0, 1.5 and 2.0) in a completely randomized design. We found statistically higher water expense efficiency of DSR sown on 5th June as compared to DSR sown on 15th May without any significant differences in growth and yield. A significant yield difference between DSR grown with irrigation regimes of IW/CPE 1.0 and 1.5 and DSR grown with irrigation regimes of IW/CPE ratio 2.0 were observed. The DSR grown with irrigation regimes of IW/CPE ratio of 1.5 resulted in significantly higher water expense efficiency than the one with IW/CPE ratio of 2.0. Obtaining a higher yield of DSR under scarce irrigation water might be a trade-off between optimum water use and maximum yield avoiding excess ground water exploitation in sub-tropical semi-arid regions of India. Our study suggests that sowing time and irrigation regimes are two important aspects of “rice production” to attain “win–win” solution. Thus, strategic and judicial use of irrigation water with management of sowing time could potentially escalate the rice production in water scarce regions of India.

Temperature-Based Phenology Modeling and GIS-Based Risk Mapping: A Tool for Forecasting Potential Changes in the Abundance of Mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is a highly invasive and a polyphagous pest of worldwide importance. Its recent outbreak and rapid spread in Indian cotton growing belt caused large scale devastation. A study was undertaken with a basic assumption that the future distribution and abundance of P. solenopsis will be affected seriously by temperature alterations due to global climate change, which might further aggravate the yield losses. The population growth potential of P. solenopsis was estimated at six constant temperatures ranging from 15 to 40 °C. The phenology models established using best fitting functions in a rate summation and cohort up-dating approach were employed in a geographic information system for mapping population growth potentials according to real-time or interpolated temperature data, for both current and future climate to predict the impact of climate change. The risks for population establishment and survival, average numbers of generations and potential population increase/year were computed using interpolated daily minimum and maximum temperatures at a spatial resolution of 10 arc minutes obtained from worldclim database (www.worldclim.org). The real-time weather station data from two selected locations across India were used to analyze within-year variation of pest population increase due to seasonal climate fluctuations. The model predicted favorable temperature range for P. solenopsis development, survival, and reproduction within a range of 20–35 °C with maximum population growth potential and shorter generation length at 30 °C. The findings revealed significant changes in P. solenopsis activity under climate change scenario, including expansion of a geographical distribution range at higher latitudes and altitudes, marked increase in the number of generations/year and increased abundance and damage activity in present distribution range in India. The study generated knowledge on temperature-dependent population dynamics and growth potential of P. solenopsis crucial for undertaking agroecoregion specific management strategies.

Phenology Modelling and GIS Applications in Pest Management: A Tool for Studying and Understanding Insect-Pest Dynamics in the Context of Global Climate Change

Intensification of agricultural yield losses due to pest aggravation in the context of global climate change has been the key focus of ecological research. In this regard, interest in forecasting models is now days growing radically among entomologists to predict the environmental suitability for new and invading agricultural insect pests. This chapter describes the approaches for development of temperature-based phenology models that helps in understanding insect behaviour and physiology under diverse environmental conditions. A few suitable illustrations are provided on how phenology models can be used for simulating variability in insect development times through stochastic and deterministic simulation functions with inclusion of temperature as a main predictor of insect development. Further, discussions were also included on linking of phenology models with geographic information systems (GIS) for mapping pest population growth potentials according to real-time or interpolated temperature data, as a tool for pest risk assessments in different agro-ecological regions and to support the development of management strategies. The concepts and approaches underlying simulation of age-stage-structured populations using cohort-updating and rate summation principle and the use of geostatistical algorithms integrated in GIS for risk mapping are described briefly.

Photosynthesis and Associated Aspects Under Abiotic Stresses Environment

Abiotic stresses are the prime reason of crop loss worldwide, reducing average yields for most of the major crop plants by more than 50%. Plants as sessile organisms are persistently exposed to changes in environmental conditions. When these changes are swift and extreme, plants generally perceive them as stresses. However stresses are not necessarily a problem for plants because they have evolved effective mechanisms to avoid or reduce the possible damages. The response to changes in environment can be rapid, depending on the type of stress, and can involve adaptation mechanisms, which allow them to survive the adverse conditions. Extreme environmental conditions, such as high and low temperatures, waterlogging and deficits, salinity, and carbon dioxide (CO2) and ozone (O3) concentrations at the leaf surface strongly affect plant growth and development. Such abiotic stresses adversely affect on physiological mechanisms associated with plant responses, adaptation, and tolerance to stresses in terms of photosynthetic mechanisms, such as CO2 diffusion through stomatal control, photosystem II repair, ribulose bisphosphate carboxylase/oxygenase (Rubisco) activity, and generation of reactive oxygen species (ROS), are susceptible to damage that causes great diminution in photosynthetic efficiency. Therefore, photosynthesis is one of the key processes to be affected by abiotic stresses, which results in decrease in CO2 diffusion to the chloroplast and metabolic constraints. Although several structural and functional components of the photosynthetic apparatus are responsive to abiotic stresses, photosystem II (PS II) and Rubisco act as the major stress sensors. In addition, it is essential to systematize current knowledge on the complex network of interactions and regulation of photosynthesis in plants exposed to abiotic stresses. In this chapter, we brought the update knowledge emphasizing on the regulation of photosynthesis and associated aspects that are affected by various abiotic stresses.

Adaptation and Intervention in Crops for Managing Atmospheric Stresses

Climate change is thevariation in the statistical distribution of weather patterns when that change lasts for an extended period of time.The relationship between climate change and agriculture is complex, both ecologically and politically. Climate variability is inherently linked to the productive capacity of agricultural production systems worldwide. In India population depends highly on agriculture and they created excessive pressure on natural resources with poor coping mechanisms.The significant negative impacts have been noticed with respect toclimate change, predicted to reduce yield by 4.5 to 9 per cent, roughly up to 1.5 per cent of GDP per year. India is more challenged withimpacts of looming climate change, and agricultural production in the country isbecoming increasingly vulnerable to climatevariability and change characterized by alteredfrequency, timing and magnitude of precipitation and temperature. Therefore, it is need of the hour to enhance resilience of agriculture to climate change through planned adaptation and mitigation strategies.

Atmospheric Stressors: Challenges and Coping Strategies

The basic principle of agriculture lies with how crop/livestock interacts with atmosphere and soil as a growing medium. Thus any deviation of external optimal atmospheric conditions affects the pathway through changes in atmospheric and edaphic/feed factors for crop/animal growth, development and/or productivity. Besides these, change and variability in atmospheric conditions have increased due to human activities to induce greenhouse gas emissions. In the continuation of current trend in carbon emissions, temperatures will rise by about 1 °C and 2 °C by the year 2030 and 2100, respectively. With warmer climate, frequency and severity of extreme weather events would increase as indicated by incidences of heat waves, extreme rains, hailstorm, etc. during recent years. Besides these, events like cloudburst, cyclone, sand/dust storm, frost and cold wave and deteriorated air quality are becoming regular events. However, the type and intensity of stress events will probably have varying impacts in different ecoregions. These events cause huge impact both in terms of mechanical and physiological on commodities across crop, livestock, poultry and fisheries. The quantum of impact on crops mainly depends on the type of stress and crop/animal/fish, its stage/age and mode of action of the stress. Management strategies for mitigation of these stresses require both application of current multidisciplinary knowledge, development of a range of technological innovations and timely interventions. It’s high time to update our knowledge regarding existing technologies and side by side explores new avenues for managing atmospheric stresses in agriculture. The first step for the scientific community will be to screen and identify species for tolerance to atmospheric stresses followed by complete insight of the biological processes behind the atmospheric stress response combined with emerging technologies in breeding, production, protection and postharvest which is likely to improve productivity and reduce losses. The type and level of stresses must be properly quantified through proper scientific planning for present as well as future references for finding mitigation and adaptation solutions. Keeping above in view, this chapter has been prepared which includes aspects covering atmospheric stresses, their challenges and coping strategies in various agricultural enterprises including crops, livestock, poultry and fisheries. This chapter will ignite the minds of all stakeholders including students and researchers to explore more in finding proper adaptation, and mitigation measures. This will pave the way for developing food and livelihood systems that will have greater economic and environmental resilience to risk.