Language: Chinese
ISBN/ISSN: 9787503862946
Published on: 2011-01
Hardcover
The walnut tree is a perennial deciduous fruit tree,with large economic values. It belongs to Juglans and Juglandaceae. Juglans consists of over 20 species distributed in Asia, Europe and the Americas. Five species originated in China, namely J. regia, J. mandshurica,J. cathayensis, J. sigillata and J. hopeiensis. Two species are widley cultivated, i.e., the common walnut and J. Sigillata. The former one widely distributes throughout the north and south of China, and the latter one is mainly distributed in the Southwest area. China is one of the major countries for walnut production. China has a long history for walnut cultivation starting in the Western Han Dynasty, and there have been many treatise about the varieties, distribution, characters, cultivation techniques and economic usage of walnuts published from A.D. 400 onwards. Traditional Chinese medicinal literatures believe that walnut is healthy to man’s brains, and the fruit, peel, seed shell, wood and leaves of walnut tree can be used in industry and many other purposes. The nucleoli is nutritious with unique flavor. Walnut is recognized as one of the four famous nuts in the world. Walnut trees can play important roles
in afforestation of waste land, soil and water conservation and improving the environment. Walnut has been extensively used by Chinese people for long time. The research on the walnut germplasm resources is of great significance in promotion of walnut production, use and expoitation of walnut resources, and breeding of new excellent varieties. In China, intensive cultivation of walnut using few productive varieties is causing genetic uniformity, and some genetic resources of walnuts are disappearing at unprecedented rates, which sometimes makes these walnut plantation more vulnerable to pests and environmental stresses. Making better use of a broader range of the walnut’s genetic diversity is becoming one optional solution to this problem. Fully using walnut germplasm resources can help scientists bring out more new varieties and increase the genetic diversity of cultivated walnut. The full spectrum of walnut dermplasm should comprise diversity of genetic material contained in traditional varieties, modern cultivars, wild species and other relatives. These resources of genetic diversity provides plant breeders with options to develop, through selection and breeding, new and more productive varieties, that are resistant to virulent pests and diseases and adapted to changing environments. Using local walnut germplasm resources, walnut breeding in China has made some achievements in the past years, breeding a large number of good varieties and superior clones. With the improvement of living standards of Chinese people, and the recognition of the nutritional value and the medical effects of walnut, the demand for higher quality walnut has been increasing,promoting the development of walnut product and expanding the use and exploitation of walnut resources. Further cultivation of high-yield, strongly-resistant, better-quality and easily-processed walnut varieties is becoming an important goal for walnut breeding in the future of China.
To summarize the research results of walnut germplasm in China and introduce the achievements to more people who are interested in it, the book Walnut Germplasm Resources in China was published by China Forestry Press in 2011. Based on the walnut germplasm resources in 15 provinces or autonomous regions and municipalities of China, the book comprehensively
introduced the walnut germplasm resources in China. The book is divided into two parts. The first part introduced the origin, cultivation history and the main usages of walnut, and the outlines of germ plasm conditions of the common walnut, pecan and beak walnut. The second part introduced all varieties of the common walnut, pecan and beak walnut, and the geographic distribution of germplasm resources, the biological characteristics and the main features of cultivation.
The book is informative, comprehensive and characteristic in both theoretical elucidation and practicality in walnut management. The book would become a good reference for the persons who are engaged in walnut geography, biology, breeding, management and other relevant fields.