Strategies to Harness Genetic Diversity in Alfalfa and Increase Crop Productivity.

Alfalfa (Medicago sativa L.) is a high yielding perennial forage legume species with extensive agricultural value worldwide.  Advances in DNA sequencing and SNP genotyping technologies can be used to understand and harness the genetic diversity of alfalfa.  Leveraging a draft alfalfa genome sequence, genotypic data and approaches to accurately phenotype plant growth and performance in a variety of conditions can facilitate the identification of traits and desirable alleles that contribute to increased plant productivity.  Target traits for improvement in alfalfa include maximizing water and nutrient use efficiency, increasing tolerance to stress conditions, grazing tolerance and persistence.  Opportunities exist to identify specific root phenotypes that result in better acquisition of water and nutrients from the soil by understanding the genetic and environmental components affecting that trait. Consistency in phenotypic data can be achieved through the use of a controlled vocabulary to uniquely describe each trait as a distinguishable feature of a developing or mature plant. Integrating basic and applied knowledge from genotyping and phenotyping approaches into an alfalfa breeder’s toolbox will enable the efficient utilization of the existing genetic diversity as part of the decision-making process of the plant breeding pipeline.  Understanding the genetic diversity of a valuable crop using phenotyping descriptions and genomics-based strategies can accelerate the development of new cultivars that are more resilient to changing environmental conditions that meet current and future demands for agricultural products.