Evaluation of effect of colored shade nets on plant growth and fruit yield of high bush blueberry in Yingyu County

Little research has been done on blueberry under shade nets in northeastern china. We used two color nets black and green with three different level of shade 30%, 50%, 70% nominal shade. We used two variety of hight bush bulueberry pulan 9 & northland. Leaf size (width, length) were measured after when all leaves matured, internodes distance, leaf size, fruit yield, and harvest delay ware recorded, In early September plant height, east and west crown, number of basal branches, and their height were assessed. We observed that internodes distance decrease with an increase of shade black 50%pulan 9& black 70 % northland showed lowest record. Leaf size (width/length) increased with an increase of shade level, black 70% of both variety showed lowest record as compared to control. fruit yield decreased with an increase of shade level in both variety, black 70 % showed the lowest weight with 1.1kg of pulan 9 and 1.8kg northland as contrast to open treatment 3.7kg and 5.8kg. Shading high bush blueberry generally delays fruit harvesting time. this experiment showed green 50%,70% of pulan 9 was ready to pick up (3,7 days) after control treatment & northland green 50%70%(4,8 days) .while black 30%50%,70% of pulan 9 was ready to pick up (5,11,14 days) after control treatment other hand northland black 30,50,70% was (6,12,15 days).the result showed increase of shade level has negative impact on growth plant bluerry specially 50% and 70%.