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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #374983

Research Project: Genetic Improvement and Cropping Systems of Warm-season Grasses for Forage, Feedstocks, Syrup, and Turf

Location: Crop Genetics and Breeding Research

Title: Natural genetic diversity of nutritive value traits in the genus Cynodon

item DE SOUZA, C.H.L. - University Of Florida
item LOPEZ, Y - University Of Florida
item MUNOZ, P - University Of Florida
item Anderson, William - Bill
item AGNOL, M. DALL' - University Of Florida
item WALLAU, M - University Of Florida
item RIOS, E - University Of Florida

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/2020
Publication Date: 11/6/2020
Citation: De Souza, C., Lopez, Y., Munoz, P.R., Anderson, W.F., Agnol, M., Wallau, M.O., Rios, E.F. 2020. Natural genetic diversity of nutritive value traits in the genus Cynodon. Agronomy. 10(11):1729.

Interpretive Summary: A forage bermudagrass (Cynodon spp.) collection that had been formed and conserved at the USDA/ARS Crop Genetics and Breeding Research Unit along with some other bermudagrass accessions from the USDA National Germplasm collection maintained at Griffin were evaluated for numerous nutritive quality traits for ruminant forage at the University of Florida. The traits evaluated were crude protein, phosphorous content, fiber content and ruminant digestibility as measured by the laboratory procedure in vitro digestible organic matter (IVDOM). The results from the very diverse set of bermudagrass forage lines were used to determine genetic parameters that estimate the ability to improve these traits through breeding. A small subset of 15 genotypes were then studied over 11 harvests over two years to determine the amount of variation due to bermudagrass genetic variability or from harvest times. From this work breeding line 240, PI-316510 and PI-3166536 presented superior nutritive value compared to Tifton 85.

Technical Abstract: The USDA National Plant Germplasm System (NPGS) Cynodon spp. collection preserves unique sources of diversity that can be explored in forage breeding. However, there is limited information on nutritive value (NV) traits for this germplasm. In this study, crude protein (CP), phosphorous concentration (P), in vitro digestible organic matter (IVDOM) and neutral detergent fiber (NDF) were determined to i) estimate genetic parameters for NV in the collection, ii) obtain genetic values for NV traits for the whole population across two harvests, iii) estimate genotype by environment interaction (GEI) for NV traits, and iv) select accessions exhibiting improved NV traits compared to ‘Tifton 85’. The experiment was setup as a row-column design with two replicates and augmented representation of three controls: Tifton 85, ‘Jiggs’ and ‘Coastal’. The whole-population was harvested twice, and data were analyzed using linear mixed models with repeated measures implemented in ASReml-R. In addition, a selected population of 15 genotypes were evaluated across 11 harvests to determine the extent of GEI. Genetic parameters revealed significant genetic variability for all NV traits, indicating potential improvements for NV through breeding. Specifically, P and IVDOM presented large variation, while NDF had lower diversity but some accessions exhibited lower NDF than Tifton 85. Low GEI, except for IVDOM, indicated genotypic stability and potential for selecting improved accessions under fewer harvests. Breeding line 240, PI-316510 and PI-3166536 presented superior nutritive values compared to Tifton 85. All results presented in this study will be incorporated into the USDA-NPGS Cynodon database, and improved accessions will be considered for public cultivar releases.