Abiotic stress and control of grain number in cereals

Grain number is the only yield component that is directly associated with increased grain yield in important cereal crops like wheat. Historical yield studies show that increases in grain yield are always accompanied by an increase in grain number. Adverse weather conditions can cause severe fluctuations in grain yield and substantial yield losses in cereal crops. The problem is global and despite its impact on world food production breeding and selection approaches have only met with limited success. A specific period during early reproductive development, the young microspore stage of pollen development, is extremely vulnerable to abiotic stress in self-fertilising cereals (wheat, rice, barley, sorghum). A better understanding of the physiological and molecular processes that lead to stress-induced pollen abortion may provide us with the key to finding solutions for maintaining grain number under abiotic stress conditions. Due to the complexity of the problem, stress-proofing our main cereal crops will be a challenging task and will require joint input from different research disciplines.

. Grain number is severely affected by abiotic stress in cereals. Breeding for reproductive abiotic stress tolerance has been hampered by unfocused screening procedures. The effect of abiotic stress is different at different stages of reproductive development and pollen abortion is a major contributor to grain loss. The fact that different abiotic stress conditions result in pollen development may provide opportunities for the design of alternative screening methods that are focused on maintenance of pollen fertility and reproductive stress tolerance in cereals.Figure optionsDownload as PowerPoint slideHighlights
► Abiotic stress affects grain number in cereals.
► Adequate screening methods for reproductive stress tolerance are missing.
► Different stresses cause pollen abortion and sterility.
► Response pathways for different stresses may converge and share the control of pollen development.
► Maintenance of pollen fertility could serve as basis for the selection of reproductive stress tolerance in cereals.