Half-Sib Matting and Genetic Analysis of Agronomic, Morphological, and Physiological Traits in Sainfoin under Nonstressed versus Water-Deficit Conditions

Half-sib matting, including polycross and openpollination, are powerful methods to obtain quantitative genetic information in breeding of forage plants. In sainfoin (Onobrychis viciifolia Scop).no prior efforts have been made to estimate the genetic parameters of traits and comparing these methods. Thirty half-sib families (16 polycross and 14 open-pollinated families) were evaluated under two moisture environments (nonstressed and water deficit) during 2010 to 2012. Water deficit decreased plant height (20.3%), plant density (51.8%), dry matter yield (45–53%), relative water content (RWC) (18.9%) and increased carotenoid content (23.9%), proline content (65.7%), specific catalase (74.4%) and ascorbate peroxidase activity (52.7%). High genotypic variation was observed for most of the measured traits. Narrow-sense heritability (h²PFM) estimates for agro-morphological traits ranged from 0.42 (leaf to stem ratio) to 0.95 (flowering date). The highest and lowest h²PFM among physiological traits were estimated for carotenoid content (0.50) and RWC (0.83), respectively. Moderate to high heritability for most traits showed the contribution of additive genetic effects suggesting phenotypic selection could be successful. The best agromorphological and physiological traits (such as plant height, plant density, dry matter yield, and RWC) under water deficit belonged to families 16 and 27. Dry matter yield had significant and positive correlation with plant height and plant density indicating indirect selection would also be effective to improve forage yield. Principal component analysis separated polycross and open-pollinated families into distinct groups. Open-pollinated families had higher mean values and general combining ability for most of the traits while polycross families had higher heritability and genetic gain from selection. This may indicate a more effective selection and a higher genetic advance in polycross families.