Heavy metal toxicity is one of the most devastating abiotic stresses. Heavy metals cause serious damage to plant growth and productivity, which is a major problem for sustainable agriculture. It adversely affects plant molecular physiology and biochemistry by generating osmotic stress, ionic imbalance, oxidative stress, membrane disorganization, cellular toxicity, and metabolic homeostasis. To improve and stimulate plant tolerance to heavy metal stress, the application of biostimulants can be an effective approach without threatening the ecosystem. Melatonin (N-acetyl-5-methoxytryptamine), a biostimulator, plant growth regulator, and antioxidant, promotes plant tolerance to heavy metal stress by improving redox and nutrient homeostasis, osmotic balance, and primary and secondary metabolism. It is important to perceive the complete and detailed regulatory mechanisms of exogenous and endogenous melatonin-mediated heavy metal-toxicity mitigation in plants to identify potential research gaps that should be addressed in the future. This review provides a novel insight to understand the multifunctional role of melatonin in reducing heavy metal stress and the underlying molecular mechanisms.

Natural and/or human-caused salinization of soils has become a growing problem in the world, and salinization endangers agro-ecosystems by causing salt stress in most cultivated plants, which has a direct effect on food quality and quantity. Several techniques, as well as numerous strategies, have been developed in recent years to help plants cope with the negative consequences of salt stress and mitigate the impacts of salt stress on agricultural plants. Some of them are not environmentally friendly. In this regard, it is crucial to develop long-term solutions that boost saline soil productivity while also protecting the ecosystem. Organic amendments, such as vermicompost (VC), vermiwash (VW), biochar (BC), bio-fertilizer (BF), and plant growth promoting rhizobacteria (PGPR) are gaining attention in research. The organic amendment reduces salt stress and improves crops growth, development and yield. The literature shows that organic amendment enhances salinity tolerance and improves the growth and yield of plants by modifying ionic homeostasis, photosynthetic apparatus, antioxidant machineries, and reducing oxidative damages. However, the positive regulatory role of organic amendments in plants and their stress mitigation mechanisms is not reviewed adequately. Therefore, the present review discusses the recent reports of organic amendments in plants under salt stress and how stress is mitigated by organic amendments. The current assessment also analyzes the limitations of applying organic amendments and their future potential.

Country bean (Lablab purpureus L.), a popular vegetable in Bangladesh, is severely affected by insect pests and diseases. Farmers’ perceptions of insect pests, diseases, and their management are critical constraints to the establishment of an effective and sustainable pest management approach for this crop. A comprehensive survey was conducted with 300 country bean farmers from six districts of Bangladesh to assess farmers’ perceptions and knowledge of the insect pests and diseases of country bean, and their management practices. The survey results show that country bean farmers have been facing varying pest problems for more than ten years. They could identify eight pests and only one beneficial insect species in their fields, including thrips and jute weevil, as new pests. Among the pests, aphids and pod borers were common in all surveyed areas. More than 80% of farmers said their bean plants were severely affected by bean yellow mosaic virus and white mold diseases. Farmers also mentioned that insect pests and diseases together caused 30–40% yield losses of this crop. About 76% of the farmers solely depended on different chemical pesticides for the production of country bean. Growers frequently used insecticides from the organophosphorus and neonicotinoid groups, and fungicides from the triazole group, to manage pests associated with this crop. Farmers start applying pesticides from the seedling stages, at three-day intervals, maintaining only two- to four-day pre-harvest intervals (PHI). Our findings provide insight into the importance of developing sustainable pest management approaches for country bean production in Bangladesh.

Being one of the major cereal crops, rice has a great effect on food security of the world population. But worldwide rice production faces severe threat due to a combination of factors like uncontrolled human rise, limited agricultural land and increasing environmental stresses. Coping with this situation is an urgent call for meeting the challenge. For overwhelming rice production by battling with this condition, scientists and researchers try their best to develop such rice varieties which can adapt to adverse climatic conditions. But, the majority of the research efforts are given on above ground parts of rice to make it stress tolerant. Root, one of the major parts of plant, remains unnoticed although it has immense possibility of adaptation under stress conditions. Fruitful and efficient utilization of limited resources are possible through healthier and competent root systems. Selection and breeding of rice genotypes with extensive root systems may contribute to more efficient use of soil nutrient resources and this ultimately influences the yield stability of rice.

Wheat is one of the major cereal crops in Bangladesh. Over the last two decades, wheat consumption has passionately amplified in Bangladesh but its production has declined due to various stress environments. Recurrent drought event due to climate change that threatens the country’s food safety has become a serious concern. To safeguard the food security, adopting suitable breeding strategies can add momentum. Developing drought tolerant wheat varieties are the definitive means of protecting the crop against hostile effects of drought. Plant breeders are exploring various breeding strategies to breed for the varieties that can cope with water deficient conditions well. Besides, breeders are consistently looking for new prospects and strategies that can boost genetic gain in yield. To endorse drought tolerance in wheat, understanding the physiological and genetic adaptation mechanisms of wheat cultivars during drought stress would provide the estimated benchmarks to adjust for suitable breeding programs. The efforts of developing drought tolerant wheat genotypes could be supported by different breeding strategies including in vitro haploid and double haploid protocols, polyploidization, development of various types of hybrids and induced mutants by utilizing both classical and molecular breeding techniques. The proposed book chapter shall discuss the pattern of drought-stress in the wheat growing regions, effects of drought stress on wheat production and suitable breeding strategies for developing drought tolerant genotypes in Bangladesh.