Field Crop 2024, Vol.7, No.6, 298-307 http://cropscipublisher.com/index.php/fc 299 2 Agroecological Requirements for Sorghum 2.1 Climate and soil preferences Sorghum is well-suited to a variety of climates, particularly those characterized by drought and high temperatures, due to its inherent drought tolerance and lower water requirements compared to other cereal crops like corn (Tonitto and Ricker-Gilbert, 2016; Kothari et al., 2019). It thrives in semi-arid regions, such as the dry savanna of West Africa and the Texas High Plains, where efficient water management is crucial for sustainable production (MacCarthy et al., 2010; Amouzou et al., 2018). Sorghum can also adapt to different soil types, including sandy soils with low fertility, as seen in the Southern Guinea Savanna of Nigeria (Akinseye et al., 2023). The crop's ability to withstand both drought and waterlogging makes it a versatile option for diverse agro-ecological zones (Tonitto and Ricker-Gilbert, 2016). 2.2 Nutritional requirements Sorghum's growth and yield are significantly influenced by nutrient management, particularly nitrogen (N) and phosphorus (P) (MacCarthy et al., 2010; Tonitto and Ricker-Gilbert, 2016). Efficient use of these nutrients is essential for optimizing yield and maintaining soil health. Studies have shown that sorghum can benefit from both organic and inorganic nutrient amendments, with yield improvements ranging from 43% to 98% depending on the management practice (Tonitto and Ricker-Gilbert, 2016). In semi-arid regions like Ghana, the application of mineral N fertilizers has been found to enhance both yield and water use efficiency, with optimal rates varying based on field management intensity (MacCarthy et al., 2010). Additionally, integrating organic matter into the soil can further improve nutrient use efficiency and crop productivity (MacCarthy et al., 2010). 2.3 Crop physiology and growth stages Sorghum's growth is characterized by distinct physiological stages, each with specific environmental and management requirements. The crop's development is influenced by temperature and photoperiod, with growth stages including germination, vegetative growth, flowering, and grain filling (White et al., 2015). Sorghum's ability to maintain functional equilibrium between roots and shoots is crucial for its adaptation to varying environmental conditions (White et al., 2015). The crop's rooting depth, for instance, can be optimized to enhance water uptake and reduce irrigation needs, as demonstrated in studies on sweet sorghum in subtropical environments (López et al., 2017). Understanding these physiological traits is vital for developing efficient cultivation models that maximize yield and resource use efficiency. 3 Genetic Resources and Varietal Selection 3.1 Breeding for edible sorghum Breeding efforts for edible sorghum have increasingly focused on utilizing advanced genetic tools to enhance crop resilience and productivity. Marker-assisted breeding has been pivotal in developing high-yielding, disease-resistant, and climate-resilient sorghum cultivars. This approach has significantly reduced the time required to introduce new varieties adapted to challenging environmental conditions (Baloch et al., 2023). Genomic selection has also been employed to predict phenotypic performance, expediting the development of new cultivars with improved traits such as drought tolerance (Charles et al., 2024). Additionally, exploring genetic diversity for traits like nitrogen use efficiency (NUE) has been crucial in developing sorghum genotypes that perform well under varying nitrogen regimes, thereby enhancing yield potential (Figure 1) (Bollam et al., 2021; Ostmeyer et al., 2022). 3.2 Stress-resilient varieties Developing stress-resilient sorghum varieties is essential for ensuring food security in regions prone to abiotic stresses such as drought and high temperatures. Breeding programs have focused on traits like stay-green, root architecture, and transpiration efficiency to enhance drought tolerance (Prasad et al., 2021). The integration of genomic prediction models has facilitated the selection of sorghum varieties that can withstand both biotic and abiotic stresses, particularly in environments with unpredictable rainfall patterns (Charles et al., 2024). Moreover, the use of epigenetic variation has shown promise in increasing yield stability and resilience under stress conditions, offering a novel approach to breeding stress-resilient sorghum (Ketumile et al., 2022).
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