Field Crop 2025, Vol.8, No.2, 51-60 http://cropscipublisher.com/index.php/fc 57 in these studies indicate that both additive and non-additive gene actions are important, making the breeding process more predictable and efficient (Makanda et al., 2010; Mengistu et al., 2020). 7.3 Market demand and adoption of hybrid sorghum varieties The market demand and adoption of hybrid sorghum varieties are driven by their superior agronomic performance and resilience to environmental stresses. High-yielding sorghum genotypes with farmer-preferred traits and resistance to diseases such as anthracnose are key factors in their adoption (Mengistu et al., 2020). The development of hybrids with high grain Fe and Zn concentrations also addresses micronutrient malnutrition, making these hybrids more attractive to farmers and consumers (Gaddameedi et al., 2020). In sub-Saharan Africa, the adoption of hybrid cultivars has been shown to enhance productivity and food security, with hybrids displaying up to 285% standard heterosis for grain yield (Makanda et al., 2010). The positive correlation between grain yield and traits such as head length and number of leaves per plant further supports the market potential of these hybrids (Makanda et al., 2010). Overall, the enhanced heterosis achieved through the use of male sterile lines not only improves yield and quality traits but also meets the market demand for high-performing and nutritionally superior sorghum varieties. 8 Challenges and Limitations 8.1 Genetic and environmental challenges in maintaining male sterility Maintaining male sterility in sorghum presents several genetic and environmental challenges. One significant genetic challenge is the stability of male sterility genes across different environmental conditions. For instance, the cytoplasmic male-sterility (CMS) system, while effective, can be influenced by environmental factors such as temperature and photoperiod, which may affect the expression of sterility (Song et al., 2020). Additionally, the genetic background of the plant can influence the stability of male sterility, as seen in other crops like soybean and wheat, where specific genetic deletions or mutations are required to maintain sterility (Nadeem et al., 2021; Yang et al., 2021). Environmental stresses such as drought and nutrient deficiencies can also impact the expression of male sterility, potentially leading to partial fertility and complicating breeding efforts (Pfeiffer et al., 2010). 8.2 Limitations of current breeding techniques Current breeding techniques for enhancing heterosis in sorghum using male sterile lines face several limitations. Traditional CMS systems, while useful, often have low resource utilization rates and can be environmentally sensitive, limiting their effectiveness (Song et al., 2020). Moreover, the development of male-sterile lines through conventional breeding is time-consuming and labor-intensive, requiring multiple generations to stabilize the trait (Indhubala et al., 2010). The reliance on specific genetic backgrounds for maintaining sterility also limits the genetic diversity that can be utilized in breeding programs, potentially reducing the overall adaptability and resilience of the resulting hybrids (Yang et al., 2021). Furthermore, the integration of modern biotechnological tools such as CRISPR/Cas9 for creating male-sterile lines is still in its nascent stages and requires further refinement and regulatory approval (Song et al., 2020; Nadeem et al., 2021). 8.3 Strategies to overcome existing challenges To overcome these challenges, several strategies can be employed. One approach is the development of more robust male-sterile lines through advanced genetic techniques such as CRISPR/Cas9, which allows for precise editing of sterility genes and can create stable male-sterile mutants without introducing foreign DNA (Song et al., 2020; Nadeem et al., 2021). Another strategy is the use of dominant genic male sterility (DGMS) technology, which can produce hybrids with high yield potential and better adaptability to environmental stresses (Wan et al., 2021). Additionally, combining CMS with genic male-sterility systems can provide a more stable and flexible breeding platform, as demonstrated in hybrid rice technology (Song et al., 2020). Enhancing the genetic diversity of male-sterile lines by incorporating diverse genetic backgrounds can also improve the resilience and performance of hybrids under varying environmental conditions (Indhubala et al., 2010; Pfeiffer et al., 2010). Finally, integrating marker-assisted selection (MAS) can expedite the breeding process by allowing for the early identification of male-sterile lines, thereby reducing the time and resources required for developing new hybrids (Yang et al., 2021).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==