Hordeum brevisubulatum ‘Mengnong No. 2’ is a new forage variety developed using traditional group selection breeding techniques. It features notable advantages in plant height, tillering capacity, and overall biomass yield. However, key molecular breeding techniques such as molecular marker identification and genetic manipulation have yet to be established for this variety, limiting improvements in important traits. Consequently, we assessed the biomass of ‘Mengnong No. 2’ against ‘Mengnong No. 1’, the most widely cultivated variety in the central and western regions of Inner Mongolia, China. We report that fresh forage, dry forage, and seed yields of ‘Mengnong No. 2’ increased by 20.6%, 31.78%, and 34.35%, respectively, compared with the control variety, indicating broad prospects for its application and promotion. To enable rapid identification of ‘Mengnong No. 2’ during its promotion and to prevent production losses caused by variety admixture, we used three screened SSR primer pairs (GST25, GST37, GST127) to construct a DNA fingerprint for five H. brevisubulatum varieties, including ‘Mengnong No. 2’. With the percentage of polymorphic bands exceeding 95%, these profiles enabled precise identification of the ‘Mengnong No. 2’ variety. Furthermore, callus regeneration in H. brevisubulatum represents a bottleneck for directed molecular breeding techniques such as genetic transformation and gene editing. Accordingly, we selected the inflorescences of ‘Mengnong No. 2’ as explants and investigated the callus induction and regeneration capacity of inflorescences at different developmental stages. We found that explants at the spikelet primordia differentiation stage exhibited the highest callus induction and regeneration efficiencies, reaching 62.7% and 72.8%, respectively. The resulting embryogenic callus lines can serve as recipients for Agrobacterium-mediated transformation or gene gun bombardment, facilitating the development of subsequent high-efficiency genetic transformation and gene-editing systems. The SSR-based variety identification system and the highly efficient regeneration technology using inflorescence-derived callus established in this study lay a solid foundation for the development of a molecular breeding system for ‘Mengnong No. 2’.
Yang et al. (Sun,) studied this question.