Characterization of diverse germplasm of sainfoin (Onobrychis viciifolia Scop.) using agro-morphological traits and AFLP molecular markers

Abstract

Sainfoin (Onobrychis viciifolia Scop.) is a perennial forage legume, widely distributed in northern temperate regions of the world. Unlike alfalfa (Medicago sativa L.), sainfoin does not cause bloat in grazing animals due to the presence of condensed tannins. However, this species is still an underdeveloped legume, with limited information available on genetic diversity, agronomic and phenotypic characteristics. The objectives of this study were: 1) to evaluate genetic variation and relationships among 38 sainfoin accessions using amplified fragment length polymorphism (AFLP) markers; 2) to measure agro-morphological traits and nutritive value of the 38 sainfoin accessions; 3) to understand the effects of seed size, seed pod removal and temperature on sainfoin seed germination. A field plots of 38 sainfoin accessions were planted in July 2014 using a randomized complete block design with four replications near Saskatoon, SK, Canada. Five AFLP primer pairs were employed to genotype 367 plants and 1,042 polymorphic AFLP bands were detected. The analysis of molecular variance (AMOVA) revealed that 84.1% of the total molecular variation was present within accessions, while 15.0% and 0.9% of the variation resided among accessions and regions (continents), respectively. Data were collected in the growing seasons of 2015 and 2016. An analysis of variance (ANOVA) revealed significant variations for all measured traits among the accessions (P<0.05). The 2-yr mean data revealed winter survival of sainfoin accessions ranged from 20–94%. Similarly, accessions showed a wide range of plant height from 37–70 cm. Forage dry matter (DM) yield ranged from 74–239 g plant−1 and seed yield ranged from 5–64 g plant−1. Similarly, wide variations were observed for nutritive values. Forage DM yield had a positive correlation with plant height (r=0.82, P<0.001), stem number (r=0.75, P<0.001), and 1000-seed weight (r=0.29, P<0.001), whereas negative correlations were found with days to flower (r=−0.57, P<0.001) and crude protein (CP) concentration (r=−0.62, P<0.001) were observed. Based on agronomic performance and nutritive value traits, the accessions were grouped into three major clusters. Seed germination of sainfoin varied significantly (P=0.047) at different temperatures with the highest final germination at 20/10°C (day/night temperature) and 15/5°C temperatures. Seed pod removal significantly (P<0.001) enhanced seed germination. The seed germination experiments suggested the possibility of decreasing seed size without affecting germination percentage of sainfoin seed within the same accession. In conclusion, the information obtained from this study on agro-morphological traits, nutritive values and genetic diversity among the 38 sainfoin accessions will be useful for future sainfoin breeding programs.