Abiotic Stress and Control of Yield in Cereals

Abstract

Abiotic stress is one of the most destructive factors affecting grain yield in cereals. Abiotic stress takes many forms, the common ones being extreme temperatures, drought, flood, salinity, and other natural disasters. The lesser-known stressors occurring infrequently are less noticeable, but they include poor edaphic conditions like pH and rock content of soil, higher than normal radiation, soil compaction, soil contamination, and some specific conditions like rapid rehydration during seed germination. In cereal crops, grain (kernel) number is the main yield component directly associated with grain yield and thus exemplifies as a global problem warranting newer approaches in cereal breeding. This chapter will examine the physiological processes impacted by abiotic stress leading to reduced grain yield. Approaches and challenges in this research area will be discussed as the world population is expected to be ~10 billion by 2050. To feed this staggering population, according to the FAO, the average world cereal yield will need to reach 5 tons/ha from its present 3 tons/ha, while crop yield is trending lower. Though numerous genes related to stress tolerance have been identified, translating them efficiently to function in the field is a challenge, plus generating a yield stability conferred by these genes and keeping it economically viable for grower is difficult. This chapter is themed around the challenge of finding ways to improve cereal grain yield as we offer perspectives on abiotic stress research.