Development of a SCAR Marker Linked to Precocious Trait in Walnut (Juglans regia) Effects of Decomposing Walnut Leaf Litter on Antioxidant Systems,Photosynthetic Characteristics and Growth of Lettuce Isolation and Identification of the Allelochemicals in Walnut (Juglans regia) Root Exudates A New Method of Micro-grafting on Walnut (Juglans regia L.) Genetic Transformation of the Trichoderma Endochitinase Gene ThEn-42 to Somatic Embryos of English Walnut