eChapters

Entomopathogens are microorganisms that infect and kill insects, mites and other arthropods and are widely employed in biological control and integrated pest management. They include bacteria, fungi, viruses and entomopathogenic nematodes. Their effectiveness depends greatly on temperature, humidity, solar radiation, rainfall and interactions among the host, pathogen and environment. Climate change can alter pest populations as well as pathogen survival, infectivity, multiplication and field persistence. These effects may enhance some microbial-control agents while reducing the effectiveness of others. This chapter introduces major groups of entomopathogens and examines their performance under present and projected climatic conditions, emphasizing their importance in environmentally responsible pest management.

4.1 Climate Change

Climate change refers to long-term shifts in temperatures and weather patterns. These shifts may be natural, such as through variations in the solar cycle. But since the 1800s, human activities have been the main driver of climate change, primarily due to burning fossil fuels like coal, oil and gas. Burning fossil fuels generates greenhouse gas emissions that act like a blanket wrapped around the Earth, trapping the sun’s heat and raising temperatures. Burning of crop residues also adds to climate changes

Examples of greenhouse gas emissions that are causing climate change include carbon dioxide and methane. These come from using gasoline for driving a car or coal for heating a building. Clearing land and forests can also release carbon dioxide. Landfills for garbage are a major source of methane emissions. Energy, industry, transport, buildings, agriculture and land use are among the main emitters.

Climate and weather strongly influence annual fluctuations in agricultural insect-pest populations. As ectothermic organisms, insects respond rapidly to variations in temperature, humidity, rainfall and wind. Climate change can modify their development, survival, reproduction, adaptation and geographical distribution. It may increase the number of generations, improve overwintering survival, alter host synchronization, encourage invasive species and reduce the effectiveness of natural enemies and existing control methods. Indirect effects also occur through changes in host-plant growth, resistance and nutritional quality. This chapter examines the responses of important agricultural insect pests to changing climatic conditions and discusses their implications for crop productivity and sustainable pest management.

Forests support diverse insect communities that contribute to pollination, decomposition, nutrient cycling and other ecological processes. Certain insects, however, become destructive pests when environmental changes weaken natural regulation and favour population outbreaks. Increasing temperature, altered precipitation, drought and land-use change can affect insect development, reproduction, survival and geographical range. Climate change may also disrupt synchronization between forest trees and associated insects, intensify native-pest outbreaks and facilitate the establishment of invasive species. Such changes can reduce tree growth, increase mortality and transform forest landscapes. This chapter examines climate-related forest-pest dynamics, ecological consequences and mitigation strategies for strengthening forest health and resilience.

Climate change affects horticultural crops through rising temperatures, irregular rainfall, extreme weather, altered carbon dioxide levels and changes in seasonal patterns. These conditions influence plant growth, flowering, fruit development, nutritional quality and geographical suitability. They also alter the development, survival, reproduction and distribution of horticultural insect pests. Warmer conditions may accelerate insect life cycles, increase the number of generations and intensify crop infestations. Changes in rainfall can either suppress pest activity or create favourable conditions for outbreaks. This chapter examines interactions among climate, horticultural crops and insect pests and highlights the need for proactive monitoring and climate-adaptive pest-management strategies to safeguard horticultural production.

Insect pollinators are essential for the reproduction of most flowering plants and contribute substantially to global crop production and food security. Bees, butterflies, moths, flies, beetles and other insects transfer pollen and support fruit and seed formation. Climate change can influence their physiology, development, activity, foraging, migration, distribution and seasonal emergence. It may also create mismatches between flowering periods and pollinator activity, reducing pollination efficiency. Drought, extreme heat, habitat loss and changes in floral resources further threaten pollinator diversity and abundance. This chapter examines the direct and indirect effects of climate change on insect pollinators and discusses conservation and management measures

Climate change is increasing the likelihood that invasive insects will establish, spread and cause economic damage in new geographical regions. Invasive species commonly possess high reproductive capacity, broad host ranges, environmental tolerance, ecological adaptability and competitive advantages. Rising temperatures and changing humidity and rainfall patterns can create favourable habitats beyond their traditional ranges. Extreme weather and global trade may further support their movement and establishment. Once introduced, invasive insects can compete with native species, disrupt ecosystems and cause serious crop losses. This chapter examines the relationship between climate change and invasive insect pests and emphasizes early detection, quarantine, surveillance, forecasting and coordinated management.

Stored-product insects damage grains, cereals, pulses and other commodities, causing quantitative losses and deterioration in food quality and nutritional value. Climate change influences temperature and humidity within storage environments, directly affecting insect development, reproduction, survival and population growth. Warmer conditions may shorten life cycles, increase the number of generations and expand the distribution of important storage pests. Poor storage structures and inadequate pest management further increase these risks, particularly in developing countries. This chapter examines the influence of changing climatic conditions on stored-product pests and emphasizes improved storage design, monitoring, sanitation and climate-adaptive management practices for protecting stored food and maintaining food security.

Introduction
 
Climate change is a result from emission of greenhouse gases (e.g. CO₂, CH₄, N₂O, etc.) that will cause atmospheric warming (IPCC, 2007). Climate change may be due to natural internal processes or external forcing such as modulations of the solar cycles, volcanic eruptions, and persistent anthropogenic changes in the composition of the atmosphere or in land use. Human induced changes in atmosphere composition are a major concern. Burning of fossil fuels, like oil, coal, and natural gas is adding CO₂ to the atmosphere.

Mites are economically important pests of agricultural and horticultural crops whose development and population dynamics are strongly influenced by environmental conditions. Rising temperatures, drought, reduced humidity and altered rainfall can accelerate mite reproduction, shorten generation time and increase infestation severity. Climate change may expand the geographical range of damaging species, alter host suitability and disturb interactions with predatory mites and other natural enemies. Increased pesticide use following outbreaks may further disrupt biological control and encourage resistance. This chapter examines climate-related changes in mite biology, distribution and pest status and presents adaptive management strategies involving surveillance, resistant cultivars, biological control and integrated pest-management practices.

Plant-parasitic nematodes are important soil-borne pests that reduce crop productivity by feeding on roots and interfering with water and nutrient absorption. Temperature, soil moisture, rainfall, carbon dioxide and host-plant conditions influence their development, reproduction, survival and geographical distribution. Climate change may allow certain nematode species to expand into new regions, complete additional generations and cause greater crop damage. Drought, flooding and altered soil conditions may also modify interactions among nematodes, plants, microorganisms and natural enemies. This chapter examines the likely effects of climate change on important plant-parasitic nematodes and discusses monitoring, forecasting and adaptive management approaches for climate-resilient crop protection.

Predatory arthropods provide valuable ecosystem services by suppressing agricultural pests and maintaining ecological balance. Important predators include ladybird beetles, lacewings, predatory bugs, spiders, mites and other groups that consume harmful insects at different developmental stages. Their small body size and ectothermic nature make them sensitive to changing temperature and moisture regimes. Global warming can affect their metabolism, development, body size, fecundity, longevity, dispersal and geographical distribution. Climate change may also disrupt temporal and spatial relationships between predators and their prey. This chapter examines the effects of climatic changes on predatory arthropods and their continuing role in natural and applied biological control.

Soil supports diverse arthropod communities, including insects, mites, springtails, spiders, millipedes and centipedes. These organisms contribute to decomposition, nutrient cycling, soil formation, microbial regulation and food-web stability. Their activities improve soil fertility, structure and overall ecosystem functioning. However, soil arthropods are highly responsive to temperature, moisture, vegetation and other environmental factors. Global warming, altered rainfall, drought and changes in soil properties can modify their diversity, abundance, distribution and ecological interactions. Despite their importance, climate-change effects on soil arthropods remain comparatively understudied. This chapter examines their ecological roles, relationships with soil properties and responses to changing climatic conditions in agricultural ecosystems.

Introduction 
Chapter 15 provides a comprehensive analysis of climate change and its profound effects on agriculture and global food systems. This chapter delves into the science of climate change, focusing on its impacts on agricultural practices, climate-smart strategies, and the role of specialized climate change centers and institutes. The chapter begins with an exploration of the impacts of climate change on agriculture, detailing how shifts in temperature, precipitation patterns, and extreme weather events affect crop yields, livestock production, and overall agricultural productivity. It highlights the vulnerabilities of different agricultural systems and regions to climate change. Climate-smart agricultural practices are central to adapting to and mitigating the effects of climate change. This section covers adaptation strategies, such as adjusting planting dates, diversifying crops, and improving water management. It also addresses mitigation strategies, including reducing greenhouse gas emissions through sustainable farming practices and enhancing carbon sequestration in soils. Adaptation and mitigation strategies are discussed in detail, with an emphasis on how these approaches can be integrated to address climate change comprehensively. The interplay between adaptation (adjusting to changing conditions) and mitigation (reducing the root causes of climate change) is examined, emphasizing the need for balanced and coordinated efforts. The chapter underscores the importance of climate change centers and institutes in addressing food security. These institutions play a crucial role in research, policy development, and the implementation of climate-smart practices. They provide valuable data, tools, and guidance for managing the impacts of climate change on agriculture. The impact of climate change centers and institutes on global warming is analyzed, focusing on how these organizations contribute to reducing greenhouse gas emissions and enhancing adaptive capacity. Their role in advancing climate science and supporting climate action is highlighted. Modern concepts in climate change centers and institutes are reviewed, showcasing innovative approaches and technologies that are shaping the field of climate science and its application to agriculture. The chapter concludes with strategies for combating food security and global warming challenges. It emphasizes the need for continued research, international collaboration, and the adoption of effective climate-smart practices to ensure sustainable agricultural systems and enhance global food security.

Climate change presents horticulture with increasing challenges including heat stress, water scarcity, erratic rainfall, extreme weather, new pest pressures, and changing crop suitability. This chapter examines strategies for developing climate-resilient horticultural systems through improved cultivars, efficient irrigation, protected cultivation, mulching, canopy management, soil-health practices, and diversification. Climate-smart production also requires better forecasting, monitoring, risk management, and resource efficiency. Future horticulture is expected to integrate biotechnology, artificial intelligence, precision agriculture, automation, renewable energy, and resilient production systems. The chapter emphasizes adaptation rather than dependence on a single technology, promoting integrated approaches that maintain productivity, quality, profitability, and ecological sustainability under changing climatic conditions.

Steps for Cloning

Prepare DNA.

Select restriction enzymes for your insert and vector, and determine the appropriate reaction buffers.

Combine the following in a microfuge tube (30 µL total volume):
2 µg DNA
1 µL Each Restriction Enzyme
3 µL 10x Buffer
3 µL 10x BSA
x µL H₂O (to bring total volume to 30 µL)

Biometric observations

The phenological stages i.e. germination, tasseling, silking, and physiological maturity were recorded from fixed mid three rows of each plot. A particular stage was supposed to be completed while 90% of the observed plant showed the characteristics of that phase and number of days was counted from date of sowing.

Days to emergence (DOE)
 
When the plant shoot pokes through the soil surface. Count the 75% seedlings emerged from at least 50% of the total rows starting from the centre. If 75% of the total expected seedlings emerged, then can be considered as 75% emergence. How the growth stages of maize are distinguished can be observed from the chart below.

6.1. Line × tester analysis

A successful approach of crop breeding programme depends on the proper choice of best parents for hybridization and the ideal selection adopted in the early generation. But, the selection of parents for hybridization programme is relatively tough in the case of complex traits like yield and their components as they governed by large number of quantitative genes which are influenced by environments and seasons. Thus, breeders often meet with difficulty to fix in advance the desirable parents which will give superior progenies. In such a situation, knowledge on the nature of gene action on such complex quantitative traits of economic importance is necessary to plan and adopt appropriate selection techniques (Simmonds, 1979) and breeding methodology.

Combining ability analysis gives useful information regarding the selection of parents in terms of the performance of the hybrids. This analysis elucidates the nature and magnitude of various types of gene action involved in the expression of quantitative traits (Dhillon, 1975). Thus, the knowledge of combining ability serves as an useful tool for the selection of plants for hybridization and further exploitation. Combining ability consists of general and specific combining ability.

Sprague and Tatum (1942) defined general combining ability (gca) as the “average performance of a line in hybrid combinations” and specific combining ability (sca) “as those cases in which certain combinations do relatively better of worse than would be expected on the basis of the average performance of the lines involved. The general combining ability provides an indication of the importance of genes of largely additive in nature, while specific combining ability indicates the importance of non-additive gene effects.

Several biometrical techniques are available to estimate the general combining ability of parents and specific combining ability of hybrids. Among them, line × tester analysis is extensively used both in self and cross pollinated crops. The advantage of line × tester analysis is that a large number of inbred lines can be evaluated than diallel analysis. Besides, it provides additional information on the performance of the specific hybrids on gene action in contrast to top cross or polycross. The line × tester analysis is an efficient biometrical approach for assessing the combining ability of parents and hybrids (Kempthorne, 1957).

Commercial Crop Breeding

The term commercial crop breeding is straightaway equivalent to ‘commercial plant breeding’ and remains largely plant breeding with slight twist that commercial plant breeding aims at delivering commercial products to be delivered to the end users that is the farmers as per the need of the consumers/ markets. Thus, the farmers plant those products (open-pollinated cultivars and hybrids) which are easily accepted by the consumers and which are easy to be handled by the traders as the products reach to the traders and then from traders to the retailers and ultimately to the consumers.

Any commercial plant breeding programme run by the private seed companies typically called as Research and Development (R & D) is carried out through various models operating. There is no fixed organizational set up and different companies adopt the working set up as per size of their programme, availability of manpower and resources, area of the breeding station and several other considerations. One thing is clear that any commercial plant breeding programme will have more numbers of crop breeders than the supporting scientists.