Introduction of American Walnuts (Juglans L.)in China

Since 1984,12 Califoria cultivars of Juglans regia, 4 black walnut species(J.major,J.hindsii,J.nigra,J.microrarpa)and paradox(J.hindsii×J.regia)have been evaluated in China.12 California cultivars of J.regia were regarded as phenologically late season,0～18 days later than the local cultivars for budbreaking.Among them, Vina,Chico and Amigo are more precocious and high yieldi.The J.nigra tree is 5 m high and over l4 cm in diameter at the age of 6 on the most favorable sites in Henan,China;6-year-old paradox tree were 6.5 m in height and 18.5 cm in diameter growing vigoyously on dry,rocky and shallow soil in mountain area,Beijing,China.