Enhancing Sorghum Yield Through Efficient Use of Nitrogen – Challenges and Opportunities

Abstract

Sorghum is an important crop, which is widely used as food, forage, fodder and biofuel. Despite its natural adaption to resource-poor and stressful environments, increasing yield potential of sorghum under more favorable conditions holds promise. Nitrogen is the most important nutrient for crops, having a dynamic impact on all growth, yield, and grain-quality-determining processes. Thus, increasing nitrogen use efficiency (NUE) in sorghum would provide opportunities to achieve higher yield and better-quality grain. NUE is a complex trait, which is regulated by several genes. Hence, exploring genetic diversity for NUE can help to develop molecular markers associated with NUE, which can be utilized to develop high NUE sorghum genotypes with greater yield potential. Research on improving NUE in sorghum suggests that, under water-deficit conditions, traits such as stay-green and altered canopy architecture, and under favorable conditions, traits such as an optimized stay-green and senescence ratio and efficient N translocation to grain, are potential breeding targets to develop high NUE sorghum genotypes. Hence, under a wide range of environments, sorghum breeding programs will need to reconsider strategies and develop breeding programs based on environment-specific trait(s) for better adaptation and improvement in productivity and grain quality. Unprecedented progress in sensor-based technology and artificial intelligence in high-throughput phenotyping has provided new horizons to explore complex traits in situ, such as NUE. A better understanding of the genetics and molecular pathways involving NUE, accompanied by targeted high-throughput sensor-based indices, is critical for identifying lines or developing management practices to enhance NUE in sorghum.

Overview of Sorghum (Sorghum bicolor. L), its Economic Importance, Ecological Requirements and Production Constraints in Kenya

“…According to Tonitto and Ricker-Gilbert [83] and Ostmeyer, et al [84] efficient use of fertilizers is key in sorghum production. The current withdrawal of Kenyan government from fertilizer market and abandonment of price controls to encourage private investors have led to improved fertilizer distribution but led to increased prices which are unaffordable to most smallholder farmers.…”

Impact of in‐season split application of nitrogen on intra‐panicle grain dynamics, grain quality, and vegetative indices that govern nitrogen use efficiency in sorghum

“…Ostmeyer et al. (2022) outlined the advantages and disadvantages of the stay‐green trait in grain sorghum. The authors stated how under optimal conditions (adequate water and N), a hybrid with increased terminal senescence that has a higher efficiency of translocating N to the grain would be more productive than that of a stay‐green hybrid.…”

Responses of sorghum to cold stress: A review focused on molecular breeding

“…However, only a few C4 plants are able to Diagrammatic illustration of sorghum development and the cold exposure effect in sorghum. The principal growth stages are used to represent the effect in early, late, or any time of exposure to cold (Ostmeyer et al, 2022).…”

“…Sugars are an energy source, but they also have other functions as Sugar, amino acid, and fatty acid metabolism response to cold stress. G6P, D-glucose-6-phosphate; G3P, D-glucose-3-phosphate; Tre6P, trehalose-6-phosphate; Tre, trehalose; TSP1, alpha-trehalose-phosphate synthase; COS, chitooligosaccharides; GSA, glutamatesemialdehyde; P5C, L-1-pyrroline-5-carboxylate; GABA, g-aminobutyric acid; P5CR, P5C reductase; P5CS, glutamate 5-kinase; GDH, glutamate dehydrogenase; d OAT, ornithine aminotransferase; MGDG, monogalactosyldiacylglycerol; DGDG, digalactosyldiacylglycerol; GAlP, galactolipase; FA, fatty acid (Ostmeyer et al, 2022).…”