From Root to Shoot: Morphological Evaluation of an International Collection of Red Clover (Trifolium pratense L.) Populations

Abstract

Red clover (Trifolium pratense L.) globally is an important pastoral species, used to strengthen pasture mixes and to produce highly nutritious forage. To ensure its continued use and effectiveness, new adaptable cultivars must be developed. Breeders have continuously harnessed diversity to improve the genetic potential of species, and a key part of this is the introduction of new wild germplasm. This material brings an assortment of genetic variation for key morphological traits for crop improvement and adaptation. A row-column experimental design was used to observe trait responses of 15 red clover populations, including 12 germplasm populations, across 3 years. Thirteen above- and below-ground traits were used to evaluate plant yield, plant persistence and root structure. As expected, the biomass production of most of the 12 wild germplasm populations was low in comparison with the cultivar controls. However, key relationships between root structure and both plant persistence and plant production were identified, with plants having either an expansive or compact root system or a mixture of both. This study explored wild germplasm material and highlights the potential genetic variation available within germplasm collections. As this is one of a few publications that look at both below- and above-ground traits, it also highlights the benefits of finding the right balance between root systems. This includes the need to breed plants that are able to manoeuvre between root systems depending on the growing conditions.