The Yongjia Early As Xiangyou Industrialization Of Key Technologies And Applications

The pummelo [Citrus grandis (L.)] production status and problems of Zhejiang province as well as research progresses were reviewed, with an emphasis on Citrus grandis (L.) Osbeck cv. 'Yongjaizaoxiangyou' production in the thesis. Critical techniques for 'Yongjaizaoxiangyou' were improved and then extended to deal with severe problems such as low yield, juice sac cracking and granulation, low fruit quality, poor production standardization, etc.Biological and agricultural characteristics of 'Yongjaizaoxiangyou' fruit growth and development were studied. Shoots with a length of 10-20 cm are in the best qualtity for fruit-bearing, however, those of less than 10 cm are most common, and those of longer than 20 cm can be fruit-bearing shoots only occasionally. Four developmental stages for a fruit were observed: (1) cell division stage for both peel and juice sac (0-60 d after full blossom); (2) rapid peel growth and slow juice sac development stage (60-90 d after full blossom); (3) rapid juice sac development stage, without growth of peel and with a thinnest albedo (90-145 d after Ml blossom); (4) fruit maturation stage (145-170 d after full blossom).Critical techniques for 'Yongjaizaoxiangyou' production were improved on the basis of knowledges on biological and agricultural characteristics of this plant. The main improved techniques are as following. (1) Technique of girdling on main branches and the stem to balance vegetative growth and flower and fruit development. All main branches beared flowers when gridled, while control is only 28.5 % of branches flowered. The yield per plant was about 70 kg for gridled, which is about 10 times more of control. (2) Technique of hand cross pollination to control juice sac cracking. 'Shijiyou' or 'Yuhuanwendan' pummelo was found to be most suitalbe pollen donors, and hand cross pollination of these pollens to 'Yongjaizaoxiangyou' significantly reduced the rate of juice sac cracking, and meanwhile, improved fruit set and fruit quality as well. The technique, when applied in combination with the technique of improving water supply, reduced the percentage of juice sac cracking to 4 %...