Field Crop 2025, Vol.8, No.2, 51-60 http://cropscipublisher.com/index.php/fc 56 In East Africa, hybrids like ICSA11 ×S35 showed up to 81.90% average heterosis for grain yield, demonstrating the potential of CMS lines to produce high-yielding hybrids suitable for the region's cultivation systems (Ringo et al., 2015). 6 Genetic Tools and Techniques 6.1 Use of molecular markers for identifying and selecting male sterile traits Molecular markers have become indispensable in the identification and selection of male sterile traits in sorghum breeding programs. For instance, the use of SSR markers has been demonstrated to effectively map male sterility genes in crops like wheat, which can be adapted for sorghum. In wheat, a recessive gene for male sterility was mapped to a specific chromosome region using SSR markers, facilitating marker-assisted selection (Yang et al., 2021). This approach can be similarly applied to sorghum to enhance the precision and efficiency of breeding programs aimed at developing male sterile lines. 6.2 Application of genetic engineering and CRISPR technology Genetic engineering and CRISPR technology offer powerful tools for the manipulation of male sterility traits in sorghum. These technologies allow for the precise editing of genes responsible for male sterility, thereby accelerating the development of male sterile lines. For example, CRISPR/Cas9 can be used to knock out specific genes that control fertility, creating stable male sterile lines that are essential for hybrid seed production. The integration of these advanced genetic tools can significantly enhance the heterosis potential in sorghum by ensuring the consistent production of high-quality hybrids (He et al., 2020; Chauhan and Pandey, 2021). 6.3 Integration of genomic selection in breeding programs Genomic selection (GS) is a cutting-edge approach that leverages genome-wide markers to predict the breeding values of individuals, thereby accelerating the selection process. In sorghum, GS can be integrated into breeding programs to improve the efficiency of selecting male sterile lines and their corresponding hybrids. Studies have shown that combining ability and heterosis for yield and other agronomic traits can be effectively assessed using genomic selection, which helps in identifying superior parental combinations for hybrid development (He et al., 2020; Kanbar et al., 2020; Mengistu et al., 2020). This integration not only speeds up the breeding cycle but also enhances the accuracy of selection, leading to the development of high-yielding and resilient sorghum hybrids. 7 Agronomic and Economic Benefits 7.1 Improvement in yield and quality traits through enhanced heterosis The use of male sterile lines in sorghum breeding has demonstrated significant improvements in both yield and quality traits through enhanced heterosis. Studies have shown that hybrids derived from cytoplasmic male sterile lines exhibit superior performance in terms of grain yield and biomass production. For instance, hybrids tested with 34 cytoplasmic male sterile lines and 3 restore lines showed grain yields ranging from 0.3 to 14.0 t/ha and aboveground biomass yields from 9.6 to 109.9 t/ha, indicating a substantial heterosis effect (He et al., 2020). Additionally, hybrids such as AKMS 22A x RSSV 9 and BJ 3A x RSSV 9 have been identified for their superior sweet sorghum quality traits, which are crucial for high biomass and ethanol yield (Indhubala et al., 2010). The exploitation of heterosis in these hybrids not only enhances yield but also improves other agronomic traits such as plant height, productive tiller rate, and harvest index, which are positively correlated with grain and biomass yield (He et al., 2020; Sandeep and Biradar, 2020). 7.2 Cost-effectiveness and scalability of using male sterile lines in hybrid seed production The use of male sterile lines in hybrid seed production is both cost-effective and scalable. The development of hybrids using cytoplasmic male sterile lines eliminates the need for manual emasculation, thereby reducing labor costs and increasing efficiency in seed production. For example, the use of thermosensitive genic male sterile (TGMS) lines in rice has shown potential for economic hybrid seed production, which can be translated to sorghum breeding programs (Shukla and Pandey, 2007). Furthermore, the scalability of this approach is evident from the successful production of 121 experimental hybrids using a line × tester mating design, which were evaluated across multiple locations, demonstrating the feasibility of large-scale hybrid seed production (Ringo et al., 2015). The significant general combining ability (GCA) and specific combining ability (SCA) effects observed
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