Heat stress, when combined with drought, is one of the major limitations to food production worldwide, especially in areas that use rainfed agriculture. As the world population continues to grow, and water resources for the crop production decline and temperature increases, so the development of heat- and drought-tolerant cultivars is an issue of global concern. In this context, four barley and two wheat genotypes were evaluated in south-eastern Russia to identify heat- and drought-tolerant genotypes for future breeding programmes by identifying suitable sowing times for specific genotypes. High temperature stress, when combined with drought during late sowing, decreased the days to visible awns, days to heading and days to ripe harvest, finally negatively affecting the growth and development of plants and resulting in a lower plant population m(-2), tillers plant(-1), plant height and dry matter production m(-2). On the other hand, low temperature in combination with early sowing increased the number of days to germination, reduced seedling stand establishment and tillering capacity, finally affecting the growth and development of the crops. Compared to overall performance and optimum sowing date, barley genotypes 'Zernograd.770' and 'Nutans', and wheat genotype 'Line4' performed best in both late (high temperature with drought) and early (low temperature) stress conditions.

Global warming has already seen a radical change in temperature regimes in Bangladesh. This review provides the first up-to-date perspective and detailed analysis of wheat research in Bangladesh and the impact that global warming will have on its agriculture, especially wheat farming.

Wheat is the most important cereal in the world. However, due to an increasing trend of rising temperatures around the world, wheat may be exposed to greater thermal stress in the near future. Therefore, the identification and development of suitable wheat varieties is an important step to resolve this threat to production and to achieve high yield, even under high temperature stress. In this context, phenology, growth and yield of three elite varieties of wheat ('Gourab' , 'BARI Gom-25' and 'BARI Gom-26') were evaluated under two sowing conditions: optimum (sown on November 15) and late heat stress condition (sown on December 27). All wheat varieties, when sown late, faced severe temperature stress that significantly affected phenology, growth and finally yield. Taking into consideration phenological variation, dry matter (fresh and dry weight) partitioning and grain yield, variety 'BARI Gom-26' performed better both in optimum and late heat stress, followed by 'BARI Gom-25'; 'Gourab' performed the least. On the basis of heat tolerance parameters [relative performance (RP) and heat susceptibility index (HSI)], 'BARI Gom-25' (RP-79%; HSI-0.7) was the best performing variety followed by 'BARI Gom-26' (RP-74%; HSI-0.9) under heat stress while 'Gourab' (RP-61%; HSI-1.3) was sensitive to heat.

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A total of 20 spring wheat genotypes were evaluated under three growing conditions (optimum, late and very late) at the research farm of the Wheat Research Center, Bangladesh to assess the variation in grain yield, protein and starch content under heat stress. All genotypes were significantly affected by high temperature stress in late and very late sowing conditions, resulting in a decrease in days to heading and maturity, ultimately affecting yield, protein and starch content. Considering yield performance, genotype 'E-8' was best under optimum (6245 kg ha -1 ), late (5220 kg ha -1) and very late sowing (4657 kg ha -1 ) conditions while 'E-40' was the worst. With respect to yield reduction, genotype 'E-72' was heat-tolerant (13% yield reduction) while 'Prodip' (49% yield reduction) was heatsusceptible. On the other hand, it was found that the percentage protein increased as heat stress increased. Under heat stress, genotype 'E-65' and 'E-60' had the highest and lowest protein content (15.5% and 12%), respectively. With respect to starch content, 'Prodip' and 'E-37' had the highest while 'E-14' and 'E-72' had the lowest content (64.8% vs. 62.9%), respectively in all sowing conditions.