ABSTRACT
In recent years, considerable efforts have been made to understand the factors controlling grain weight in wheat. Under stress such as heat and drought, reduction in grain weight contributes significantly to the loss of grain yield. The yield components related to yield stability under heat and drought stress have been evaluated and efforts have been made to reveal the mechanisms of tolerance under a stressed condition. The agronomic traits from vegetative to reproductive phase have been significantly correlated with grain filling in wheat. Several genes and QTLs have been identified that determine the grain size and weight. The heat and drought-tolerant wheat cultivars have a higher biomass accumulation, well-developed root system, longer duration, and rate of grain filling and stronger sink activity.
