Abstract
Alfalfa is planted in more than 30 million hectares worldwide, but despite its popularity in temperate regions, it is not widely grown in subtropical agroecosystems. It is critical to improve alfalfa for such regions, considering current predictions of global warming and the increasing demands for animal-based products. In this study, we examined the diversity present in subtropical alfalfa germplasm and reported genetic parameters for forage production. An initial screening was performed from 2014 to 2016, evaluating 121 populations from different subtropical origins. Then, a breeding population was created by crossing selected plants, resulting in 145 full-sib and 36 half-sib families, which were planted in a row-column design with augmented representation of three controls (‘Bulldog805′, ‘FL99′ and ‘UF2015′). Dry matter yield (DMY), canopy height (AH), and percentage blooming (BLOOM) were measured across several harvests. Moderate narrow-sense heritability and high genetic correlations between consecutive harvests were estimated for all traits. The breeding line UF2015 produced higher DMY than FL99 and Bulldog805, and it could be a candidate cultivar release. Several families produced higher DMY than all checks, and they can be utilized to develop high yielding and adapted alfalfa cultivars for subtropical agroecosystems.
Highlights
Subtropical agroecosystems offer unique abiotic and biotic challenges for agriculture production.Forage breeders aiming at developing cultivars for subtropical regions are challenged to identify cool-season species with sufficient pest/disease resistance [1], while selecting warm-season species that can extend forage production during transition periods [2,3,4]
Breeding Program exhibited high dry matter yield (DMY), for harvests performed after the summer 2015 (Figure 2A,B)
Fifteen populations from Argentina and thirteen from other United States (US) sources produced more than 1000 kg DMY/ha per harvest on average (Figure 2A,B)
Summary
Forage breeders aiming at developing cultivars for subtropical regions are challenged to identify cool-season species with sufficient pest/disease resistance [1], while selecting warm-season species that can extend forage production during transition periods [2,3,4]. Alfalfa (Medicago sativa L.) is known as the queen of forages [6] and is the most important forage legume in the world, grown in more than 30 million hectares [7]. It is the fourth most valued crop in the United States (US) after corn, soybean, and wheat, with an estimated value of $8.8 billion [8]. With the current predictions of global warming [11], the tropical savanna climate type is likely to Agronomy 2020, 10, 742; doi:10.3390/agronomy10050742 www.mdpi.com/journal/agronomy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
