Youfeng Zhang

1 INTRODUCTION Walnut (Juglans regia L.) is native to Central Asia. It is currently planted throughout Southern Europe, Australia, China, USA, and Southern South America (Slatnar et al., 2015). The estimated production of inshell walnut was 3500,172 t in 2021. Walnut, one of the most versatile tree nuts intended to produce edible nuts and woody oil (Rusu et al., 2020), has become a hot research topic in recent years due to its increasing annual yield and reported nutritive values. Gao et al.