Walnut fruit forests and diversity of walnut tree (Juglans regia L.) in Kyrgyzstan.

摘要

The unique walnut-fruit forests are found in the south of Kyrgyzstan, occupying 631 thousand hectares. They are regarded as a genofund of valuable trees and bushes of approximately 180 species (Kolov, 1995). Growing on the slopes of mountains of various expositions and steepness, walnut-fruit forests carry out soil-protective, water-security and water-regulating role. The largest rivers of Central Asia originate in the mountains of Kyrgyzstan and they provide areas of Uzbekistan and Kazakhstan with water. Despite of this rather large territory, walnut forests of Kyrgyzstan have low fruit productivity. According to recent research, the productivity of walnut stands is ranging from 40 kg to 350 kg from 1 hectare, depending on the conditions of its environment. Selection of walnut has a long history, and was carried out by a method of simple selection out of the natural seed population of high-yielding plants with high quality walnuts. And up to now, this method is basic. The basic criteria of grade selection were high productivity and good commodity qualities of walnuts. During post-war time, the selection of walnut has been continued first by Prutenskiy D.I., then by Shevchenko B.S. (from 1958 to 1995). Within this time, 280 forms of walnut were selected and described, 7 forms out of them have been submitted on state quality testing. At the time of selection, the special attention was paid to early fruit bearing forms. The 20 pieces of early fruit bearing walnut forms were selected as seed and best quality trees. 3 forms were selected on special attributes: Bomb (on size of a fruit), Paper (on thickness of a shell), Clustering (by amount of fruits on a fruit steam). These forms are perspective to use on bringing out the new grades of walnut. The most perspective walnut forms were selected by the estimation results on a complex of biologically and economically valuable attributes. These best walnut forms are recommended to use as a seed material for leshozes (state forest farms), stakeholders for creation of high-yielding cultures and plantations in the walnut-fruit forest zone of Kyrgyzstan..