Genetic variability in Iranian sainfoin (Onobrychis viciifolia Scop.) landraces by morphological characteristics

Abstract

The sainfoin (Onobrychis viciifolia Scop.) is an ancient fodder crop traditionally cultivated in Mediterranean climates, yet its cultivation has dwindled in favor of other forage options across many regions. We investigated the diversity among 32 sainfoin landraces sourced from various parts of Iran, analyzing 18 distinct traits over two seasons (2022 and 2023) using a randomized complete block scheme. Notable variations were observed across the majority of measured characteristics, whereas the coefficient of variation ranged from 10.5–6.8% (for days to seed filling initiation) to as high as 63.2% and 70.8% (for inflorescence dry weight) in the first and second years, respectively. Principal Component Analysis (PCA) highlighted significant variability, with the first four components explaining 83% of the variance in 2022 and 78% in 2023. When plotting PCA1 against PCA2 for both years, distinct groups emerged, revealing three discernible groups of sainfoin landraces. Notably, certain landraces consistently grouped together across both years, including G1 (Bonab), G3 (Marand), and G11 (Urmia) from the northwest, G23 (Khomeyn), G24 (Arak), and G30 (Khansar) from the central region, and G26 (Asadabad) from the western, alongside G28 (Damavand) from the north. These landraces, originating from diverse geographical locations, were identified as particularly promising due to their distinct traits. Our findings underscore the rich morphological diversity present in current sainfoin landraces, suggesting ample opportunities for genetic improvement initiatives. These insights hold relevance for future breeding efforts aimed at enhancing specific traits through strategic crossbreeding of parent plants.