Field Crop 2025, Vol.8, No.1, 1-10 http://cropscipublisher.com/index.php/fc 6 5.3 Enhancing genetic diversity In recent years of sorghum breeding, experts have found that genetic diversity is particularly important. In the past, we always focused on those high-yield parents and repeatedly bred them, but the gene pool became narrower and narrower. Later, someone came up with a solution-to bring those inconspicuous local varieties and even wild germplasm to "match" (Jordan et al., 2011). You know what, this tossing has a really good effect. It not only preserves genetic diversity, but also unexpectedly harvests a lot of excellent traits that adapt to special environments (Figure 3). Take climate change for example. Now pests and diseases are becoming more and more difficult to deal with, but relying on this "wide-ranging" hybridization strategy, the new varieties bred are obviously more resistant (Otwani et al., 2023). Although the process is a bit troublesome, for long-term considerations, this "not putting all eggs in one basket" approach is indeed wise. Figure 3 Molecular regulations involved in the response to and tolerance of abiotic stresses in sorghum. For each of the four abiotic stresses (drought, heat, cold, and salinity and alkaline), the candidate genes (transcription factors in red), metabolites, and physiological processes are depicted in three layers (from the innermost to outermost layer, respectively) (Adapted from Tu et al., 2023) 6 Challenges and Limitations of Hybrid Breeding 6.1 Technical and economic barriers Sorghum hybrid breeding is easier said than done. Take the breeding of Guinea sorghum in West Africa as an example. It is not enough to know how to breed. The genetic characteristics of each parent must be understood clearly (Kante et al., 2019). However, the most troublesome thing is the wild germplasm. Although the genetic diversity is preserved, the hybrid offspring are often not up to standard, which makes breeders have to try every possible way to preserve the good traits (Jordan et al., 2011). When it comes to economic issues, it is even more
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