Phenotypic Variation Among and within Thirty Accessions of Onobrychis Viciifolia Examined Under Climate Change Scenarios.

Sainfoin (Onobrychis viciifolia L.) is a highly beneficial forage legume from both an animal health and environmental perspective due to its anthelmintic and anti-bloating properties, and its potential to reduce greenhouse gas emission. Despite these advantages compared to other forage species, only a few cultivars are available on the seed market.

In order to assess the existing variability in yield, morphological features, as well as levels in bioactive compounds (polyphenols) that could be exploited in breeding programs, we tested thirty accessions of sainfoin from a wide range of geographic origins and status of cultivation. Suitability of these accessions for climate change scenarios (drought stress) was also tested. Polyphenols, such as condensed tannins (CT) and flavonoids, were analyzed on an individual plant basis for 600 plants using a UPLC-MS-MS system.

For the evaluated agronomic and chemical traits, a large phenotypic variability was found, both within and among accessions. Yield losses resulting from drought ranged from 0 to 90%, indicating a high potential for adaptation of new cultivars to weather extremes as projected under climate change by breeding. Chemical analysis uncovered a large range of CT concentrations with means of accessions between 23 and 47.5 mg CT / g dry matter (DM) and single plants ranging between 10.4 and 62.6 mg CT / g DM. If grouped by their origin, mean CT concentrations varied between 23.6 mg/g for Polish accessions, up to 37.6 mg/g for Spanish accessions. Generally, cultivars showed lower CT concentrations (23.8 mg/g) compared to wild accessions (33.5 mg/g). Time of harvest and drought stress, both affected CT concentration, with time of harvest increasing CT concentrations by a factor 2, while drought stress resulted in a roughly 30% increase in CT concentration.

In conclusion, sainfoin has great potential for forage production in dry climates. The phenotypic variation observed in this study constitutes a promising starting point to further improve agronomic and chemical traits of sainfoin by breeding.