2013 Annual Report
1a.Objectives (from AD-416):
1. Identify alfalfa genetic markers associated with resistance and adaptation to abiotic stresses. Emphasis should be on markers associated with water-use efficiency that may aid adaptation of alfalfa production to variations in water availability associated with climate change and reductions in water resources available for irrigation. (NP215 C3: PS H1)
2. Identify alfalfa genetic markers associated with resistance and adaptation to biotic stresses. Emphasis should be on markers associated with diseases, nematodes and insect pests associated with irrigated alfalfa production systems. (NP215 C3: PS H1)
1b.Approach (from AD-416):
The research project will utilize short sequence repeats (SSR) and single nucleotide polymorphisms (SNP) technologies to identify genetic markers associated with resistance and adaptation of alfalfa to abiotic and biotic stresses. Markers will be validated through cooperative research collaborations with ARS scientists in Prosser, WA; Logan, UT; Madison, WI; and St. Paul, MN. Emphasis will be placed on markers associated with water-use efficiency and disease and pest resistance.
The project was without a lead scientist until May 2011. Since then, it has been redirected to MPPL. Preliminary data have been collected on the new replacement project 1245-21000-268-00D.
Currently, programs in breeding alfalfa for tolerance to salinity are based on recurrent phenotypic selection. Improved methods are needed. Molecular markers are powerful tools in replacing traditional bioassays and phenotype-based selection systems. Molecular markers can greatly facilitate identification of quantitative trait loci (QTL, genetic factors) related to important agronomic traits. Salinity tolerance is a complex polygenic trait, which contributes to the difficulties in breeding aimed at producing salt-tolerant alfalfa varieties. Over the life of the project, we have identified over 6,000 simple sequence repeats (SSRs) or microsatellite genetic markers that are associated with response of alfalfa to conditions of salinity; the markers belong to 3,183 different genes. After validation, the SSRs can be used in quantitative trait mapping and marker-assisted selection in alfalfa breeding programs. The insights gained in this project led to new focus on the regulation of gene expression during alfalfa growth and development and on the role of gene expression in stress tolerance. The findings revealing molecular markers that are associated with resistance and adaptation to abiotic stresses provided impetus for visualizing new research priorities.