Phenology, Growth and Yield of Three Wheat (Triticum aestivum L.) Varieties as Affected by High Temperature Stress

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.