Land Institute researchers Kathryn Turner, Muhammet Şakiroğlu, Brandon Schlautman, and former Research Resident Abigail Han co-authored a paper evaluating the risk that alfalfa mosaic virus poses to kura clover, a perennial groundcover crop that exhibits benefits to soil health and soil fertility.

Abstract

Perennial groundcover (PGC) research is an expanding field of study focused on utilizing the soil-protecting characteristics of perennial plants as permanent intercrops in row-crop agriculture systems. However, there are some risks that PGC could serve as a “green bridge” between cash crops. Alfalfa mosaic virus (AMV) is one such disease that could infect legume PGCs, like kura clover (Trifolium ambiguum M. Bieb), and potentially be transmitted to cash-crop companions (e.g., soybean). The objectives of the current study were to (i) evaluate AMV symptoms and susceptibility in kura clover and (ii) explore population structure and genetic diversity patterns utilizing simple sequence repeat markers across the United States Department of Agriculture National Germplasm Plant Service kura clover collection and various breeding populations from the University of Minnesota. Results showed that 96% tested kura clover field plants had AMV infection and the rate of seed transmission from parent to offspring was 0.4%. Genetic structure among kura clover germplasms generally revealed a ploidy-based separation where diploid and hexaploid cytotypes from distinct genetic clusters and tetraploid germplasm manifest an intermediate pattern. The results indicated substantial AMV sensitivity among broadly based kura clover germplasm, and the risks of both yield losses and “green bridge” due to AMV infection in kura clover should be considered.

Plain language summary

Kura clover is a hardy perennial used to protect soil and fix nitrogen, but is not widely grown due to its slow seed growth. It is being studied for use in systems that help improve soil health. However, kura clover can be affected by alfalfa mosaic virus (AMV), which causes leaf damage and reduces plant quality. In this study, we tested over 800 kura clover plants and found AMV in most, but some plants showed resistance. We also discovered that although the virus can spread through seeds, it is rare. We also examined the genetic diversity of kura clover in different countries and found that there is segregation by chromosome ploidy. Most of the genetic differences are within each ploidy group, not between ploidy groups. This information will help us understand how to grow kura clover for better resistance to viruses and better soil health.