Significance of First Leaf Type to Growth of the Sainfoin Seedling 1

The incidence of unifoliolate and trifoliolate first leaves and the importance of first leaf type to photosynthesis and growth of sainfoin ( Onobrychis viciaefolia Scop.) seedlings were studied. Sainfoin accessions had a higher proportion of unfoliolate than trifoliolate first leaves. The percentage of trifoliolate first leaves varied among 30 sainfoin accessions from 1 to 50%. Frequency of fist leaf types was not related to seed size, but leaf area within a type increased significantly with seed size. Trifoliolate first leaves had more area than unifoliolate leaves. Seedlings with trifoliolate first leaves had higher rates of net carbon enchange (NCE) and grew more rapidly during the early seedling growth period. However, forage yields of seedlings with unifoliolate or trifoliolate first leaves were similar when seedling‐were grown to 8 weeks of age in the greenhouse or to maturity in the field.