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ARS Home » Pacific West Area » Pullman, Washington » Plant Germplasm Introduction and Testing Research » Research » Publications at this Location » Publication #411842
Research Project: Enhancing Resistance to Biotic and Abiotic Stresses in Alfalfa

Location: Plant Germplasm Introduction and Testing Research

Title: Identification of genetic loci associated with protein and fiber digestibility in alfalfa

Author
item LIN, SEN - Washington State University
item MEDINA, CESAR - Washington State University
item PATEL, SMIT BIPINCHAND - Washington State University
item Xu, Zhanyou
item Zanton, Geoffrey
item COMBS, DAVID - University Of Wisconsin
item WANG, GUOJIE - Pennsylvania State University
item SHEWMAKER, GLENN - University Of Idaho
item FRANSEN, STEVEN - Washington State University
item LLEWELLYN, DON - Washington State University
item NORBERG, STEVEN - Washington State University
item Yu, Long-Xi

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2024
Publication Date: 2/18/2025
Citation: Lin, S., Medina, C., Patel, S.R., Xu, Z., Zanton, G.I., Combs, D., Wang, G., Shewmaker, G., Fransen, S., Llewellyn, D., Norberg, S., Yu, L. 2025. Identification of genetic loci associated with protein and fiber digestibility in alfalfa. Crop Science. 65(1). Article 70004. https://doi.org/10.1002/csc2.70004.
DOI: https://doi.org/10.1002/csc2.70004

Interpretive Summary: In this study, We investigated protein and fiber digestibility of 200 alfalfa accessions. Field trials were conducted in 3 different locations for 2 years. Leaf and stem samples were collected for chemical analysis of protein and fiber digestibility. Phenotypic data of 15 digestibility-related traits were measured and collected. The data were used for genome-wide association studies (GWAS) in combination with DNA markers in the same panel of accessions. A total of 22 DNA markers associated with 13 traits were identified by GWAS. These markers and linked genes are helpful for understanding the genetic factors that affect the alfalfa forage digestibility in different environments. Together with formerly identified markers associated with fiber digestibility, they can be used for marker-assisted selection in breeding programs, enabling more efficient development of alfalfa varieties with improved feeding quality.

Technical Abstract: Alfalfa (Medicago sativa), known as the queen of forages, is a versatile and valuable forage crop that holds significant importance in agriculture due to its myriad benefits for livestock. Ruminants benefit from alfalfa's digestible fiber and protein, contributing to improved feed efficiency and milk production. However, alfalfa protein is rapidly and extensively degraded in rumen, and it is a challenge to maximize the efficiency of the forage crude protein utilized as metabolizable protein by ruminant livestock. In this study, the phenotypic data of 15 traits related to forage digestibility were collected from 200 alfalfa accessions planted at three different locations for two years. The performance of these accessions showed dramatic variations by location, indicating that environmental factors play important roles on alfalfa digestibility. Twenty-two significant genetic markers associated with 13 traits related to forage digestibility were identified by GWAS. Among them, 7 markers were associated with more than 1 trait, although the significant markers varied by year and location. The digestibility-related markers and associated genes identified in this study will help to better understand the genetic basis of forage digestibility and its interaction with environments.