The Effects of Harvest Stage and Cold Storage Duration on Fruit Bud Quality of ''Shinko'' Pear Scion in Taiwan
Date Issued
2009
Date
2009
Author(s)
Tsai, Shih-Tsung
Abstract
‘Hsinko’ pear scions were collected from Lishan (2000 m in altitude) every two week since Oct. 19th, 2007 for two experiments, the first was flower development and variation of nutrient content in ‘Hsinko’ pear branches from Lishan and the second were the effect of harvest date on cold storage duration and quality of Hsinko’ pear scions from Lishan. Bud burst rate were near or over 90% after sufficient cold storage, which is not significantly different from those imported from Japan. Blooming date was advanced, number of flowers and rate of fruit set was promoted as delayed action of harvest date, but scions harvested on Jan. 25th, 2008 did not perform as expected. Scions harvested later than mid Dec. performed as well as those imported from Japan, and scions harvested at early and mid Jan. performed better than Japanese scions. Carbohydrates of pear branches were majorly composed of 80% ethanol soluble solid and with starch as minor during sampling period. 80% ethanol soluble solid raised from 114.33 mg/g DW of branches harvested on Oct. 19, 2007 to 168.73 mg/g DW of branches harvested on Nov. 30, 2007, it decreased later on but with a level over 130 mg/g DW, and branches harvested on Jan. 25th, 2008 performed as those harvested on Oct. 19th, 2007. Content of starch kept low without big fluctuation at about 20 mg/g DW, therefore, fluctuation tendency of total carbohydrates mainly followed tendency of 80% ethanol soluble solid. Nitrogen was raised from 9.3 mg/g DW to 12.0 mg/g DW and decreased slightly to 10-11 mg/g DW in branches. Pear leaves in Lishan fall off completely during early Dec. Total carbohydrates of leaves sampled on Oct. 19, 2007 was 57.71 mg/g DW, but decreased to 43.9 mg/g DW two weeks later and kept at this level until defoliation. Nitrogen content was about 18 mg/g DW for the first three sampling of leaves and decreased to 14 mg/g DW on Nov. 30, 2007, which indicated degradation of nitrogen and preparation of defoliation. Carbohydrate content of pear scions might be the major reason for variation of the results. Harvest date of ‘Hsinko’ pear scions should be between Dec. to mid Jan. according to performance of bud burst, blooming, fruit set and plant nutrient analysis.he rate and uniformity of bud burst of ‘Hsinko’ pear scions from Lishan were enhanced as delayed action of harvest. After cold storage in 5℃, rate and uniformity of bud burst were greatly improved, so were the number of flowers and rate of fruit set after grafting. Based on the performance of rate and uniformity of bud burst, rate of flowering, number of flowers and rate of fruit set, ‘Hsinko’ pear scions from Lishan harvested on Nov. should be cold stored in 5℃ for over 4 weeks, those harvested on Dec. should be cold stored for 3 weeks, those harvested on early Jan. should be cold stored for 2 weeks, and those harvested on late Jan. should be cold stored for 1 week. Excess cold storage, however, would deteriorate performance of scions after grafting. On account of the above results, cold storage period of pear scions produced from high elevation areas in Taiwan could be shortened as delay action of harvest date. Appropriate harvest date should be between Dec. to mid Jan. Cold storage was of necessity, as the earlier the date of harvest, the longer the period of cold storage. Domestic pear scions perform as well as those imported from Japan if harvested at suitable time and cold stored for an optimal period.
Subjects
pear scion
top-grafting
Type
thesis
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