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ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #316343

Research Project: Develop Improved Plant Genetic Resources to Enhance Pasture and Rangeland Productivity in the Semiarid Regions of the Western U.S.

Location: Forage and Range Research

Title: Mapping fall dormancy and winter injury in tetraploid alfalfa (Medicago sativa L.)

item LI, XUEHUI - North Dakota State University
item ALARCON-ZUNIGA, BALDOMERO - University Of Chapingo
item KANG, JUNMEI - Chinese Academy Of Agricultural Sciences
item TAHIR, M - University Of Agriculture - Pakistan
item JIANG, QINGZHEN - Samuel Roberts Noble Foundation, Inc
item WEI, YANLING - University Of California
item REYNO, RAFAEL - National Institute For Agricultural Research (INIAP)
item Robins, Joseph
item BRUMMER, E - University Of California

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2015
Publication Date: 7/17/2015
Citation: Li, X., Alarcon-Zuniga, B., Kang, J., Tahir, M., Jiang, Q., Wei, Y., Reyno, R., Robins, J.G., Brummer, E. 2015. Mapping fall dormancy and winter injury in tetraploid alfalfa (Medicago sativa L.). Crop Science. 55:1-17.

Interpretive Summary: Alfalfa fall dormancy and winter injury generally exhibit an inverse relationship. To better understand the genetic basis of these traits, we developed a genetic map of a tetraploid alfalfa population and mapped associated genomic regions for both regions onto it. Data for the mapping of associated genomic regions came from four Iowa environments and included fall plant height, winter injury, and shoot, crown, and root mass. Seventy-one genomic regions exhibited association with at least one of these traits either across or within the environments. The general lack of regions associated with both fall dormancy and winter injury supported the observation that these traits are not genetically related. These results suggested that alfalfa may be improved for both traits simultaneously.

Technical Abstract: Alfalfa is a widely planted perennial forage crop. Dormancy in autumn (fall dormancy) is generally negatively correlated with winter injury in alfalfa. To understand the genetic basis of the two traits, we identified quantitative trait loci (QTL) controlling autumn growth and winter injury using a tetraploid alfalfa F1 population. In total, 601 marker alleles were scored from 78 RFLP, 123 SSR, and 48 SNP markers. Linkage maps were constructed for each parent separately. Both maps contained eight linkage groups (LGs), with a length of 898 cM for WISFAL-6 and 845 cM for ABI408. Using interval mapping, we identified 15 QTLs from an across environment analysis and 71 QTLs within individual environments for autumn plant height, winter injury, and autumn shoot, crown, and root biomass across four Iowa environments. Of the 71 QTLs, 42 were identified at 18 chromosomal locations that were identified in multiple environments for the same trait. Possibly pleiotropic QTLs that contributed to dry weight of shoot, crown, and taproot were found, which partially explained the observed genetic correlations between those traits. However, few QTLs were related to both autumn plant height and winter injury, supporting the observation of no genetic correlation between the two traits in this study. These results indicated that the two traits could be manipulated independently and possibly efficiently improved using marker-assisted selection. Because most QTL identified in this study were mapped to intervals of at least 10 cM, validation and localization in additional populations are needed to facilitate application of marker-assisted selection.