The incidence of short episodes of high temperature in the most productive rice growing region is a severe threat for sustainable rice production. Screening for heat tolerance and breeding to increase the heat tolerance of rice is major objective in the situation of recent climate change. Replacing sensitive genotypes with heat tolerant cultivars, modification in sowing time, and use of growth regulators are some of the adaptive strategies for the mitigation of yield reduction by climate change. Different strategies could be adopted to enhance the thermos-tolerance of rice by (1) the modification of agronomic practices i.e., adjusting sowing time or selecting early morning flowering cultivars; (2) induction of acclimation by using growth regulators and fertilizers; (3) selecting the genetically heat resistant cultivars by breeding; and, (4) developing genetic modification. Understanding the differences among the genotypes could be exploited for the identification of traits that are responsible for thermo-tolerance for breeding purpose. The selection of cultivars that flowers in early morning before the increase of temperature, and having larger anthers with long basal pore, higher basal dehiscence, and pollen viability could induce higher thermo-tolerance. Furthermore, the high expression of heat shock proteins could impart thermo-tolerance by protecting structural proteins and enzymes. Thus, these traits could be considered for breeding programs to develop resistant cultivars under a changing climate.

Grain legumes, serving as vital sources of starch, protein, and oil, play a pivotal role in ensuring food security. However, global climate change poses an enhanced risk to legume production by elevated temperatures. The reproductive process, determining grain yield, is highly sensitive to heat stress, primarily affecting pollen and ovule infertility and reducing fertilization rates. Consequently, this leads to smaller seeds and reduced yield due to impaired grain setting and abortion. This review outlines the reproductive responses to heat stress in both male and female development and fertilization processes, while also examining heat-tolerant physiological and molecular mechanisms. Looking ahead, the development of heat-resistant genomes can be pursued by improving physiological processes through molecularly linked genetic engineering approaches to cope with these challenges posed by global warming.

Weeds are one of the major biological threats to higher rice productivity worldwide. Various cultural, biological, physical and chemical practices affect the composition and intensity of weeds in rice fields. Generally, weeds can be controlled through herbicides; nevertheless, chemical weed control is not a sustainable option on a long term. Various agronomic practices such as the use of tolerant cultivars, adjusting sowing time, tillage permutations and plant geometry may reduce the weed pressure in rice. Integrated approaches for weed management, emphasizing on the combination of management practices and scientific knowledge, may reduce the economic costs and improve weed control owing to the complexity of the weed community. The present chapter reveals the role of planting geometry and herbicides as weed management strategies in rice, and discusses the issue of herbicide resistance associated with chemical weed control. Moreover, the research and knowledge gaps in rice weed management through planting geometry and herbicides were also highlighted.

Maize is a vital cereal crop enhancing food security. Optimizing plant density is a common practice to increase crop yield. This study investigates the impacts of high plant density on the biochemical composition, dry matter accumulation (DMA), photosynthesis-active radiation (PAR), radiation use efficiency (RUE), grain production, and stalk lodging in maize cultivation. Five plant densities (4.5, 6, 7.5, 9, and 15 plants m-2) referred to as PD4.5, PD6, PD7.5, PD9, and PD15, respectively, were tested on three maize hybrids, Zhengdan 958 (ZD958), Longping 206 (LP206), and Jinqiu 119 (JQ119), at the Mengcheng Research Station during 2016 and 2017. High plant densities increased PAR, RUE, DMA, and grain yield and led to a higher incidence of stalk lodging. The highest grain yields were achieved at PD6 (9.44%) and PD7.5 (2.98%), while yields decreased at PD15 (12.5%) due to a 60% increase in lodging. Under high plant density, internodes experienced rapid accumulation of carbohydrates but ceased elongating, expanding, and developing structural carbohydrates. Stem bending resistance positively correlated with cellulose, hemicellulose, and lignin content (0.9293**, 0.8572**, 0.8976**), as did stem crushing resistance with the same components (0.9096**, 0.8372**, 0.8738**). The present study’s outcome will help determine the optimum plant density to improve food security and enhance maize yield under different climatic conditions.