FRUIT AND NUT CHARACTERISTICS OF PROMISING PERSIAN WALNUT TREES IN VIETNAM
NGUYEN HUY SON
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
NGUYEN TOAN THANG *
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
DANG VAN THUYET
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
NGUYEN QUANG HUNG
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
NGUYEN HUU THINH
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
VU TIEN LAM
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
NINH VIET KHUONG
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
NGUYEN VAN TUAN
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
PHUNG DINH TRUNG
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
TRAN HOANG QUY
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
PHAM QUANG TUYEN
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
HOANG THANH SON
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
TRINH NGOC BON
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
HO TRUNG LUONG
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
DUONG QUANG TRUNG
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
NGUYEN THI XUAN MAI
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
LY THI THANH HUYEN
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
NGUYEN THI THU PHUONG
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
DAO TRUNG DUC
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
NGUYEN THI HOAI ANH
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
MAI THI LINH
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
BUI THE DOI
Vietnam National University of Forestry, Xuan Mai Town, Hanoi, Vietnam.
TRAN VAN DO
Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
*Author to whom correspondence should be addressed.
Abstract
Persian walnut (Juglans regia L.) is the most economically important cultivated species for timber and nutritious nuts among 21 walnuts worldwide. Walnut has been planted in Vietnam personally in a small number of areas in Northern provinces sharing borderlines with China. The objective of this study was to survey characteristics of fruits and nuts of 15 J. regia promising trees and discuss their suitability as plus trees serving for intensive plantation. The results indicated that fruit diameter ranges 40.41-49.7 mm, fruit weight ranges 38.12-70.81 g, nut diameter ranges 24.19-34.96 mm, and nut weight ranges 9.07-25.26 g. The nut to fruit ratio for diameter ranges 57.8-70.4% and for weight ranges 20.4-35.7%. There existed positive linear relationships between fruit weight and nut weight for 10 of 15 promising trees with regression/R2 >0.5. While relationships between fruit diameter and nut diameter generally did not exist or existed with low regression (R2 <0.3). It is concluded that six of 15 promising trees could be selected as plus trees for intensive plantations through grafting technique. Those plus trees have a nut to fruit ratio for weight >30% and high regressions between fruit weight and nut weight.
Keywords: Kernel, nut diameter, nut to fruit ratio, nut weight, plus tree, shell thickness.