Study of Correlation between Green-head Symptom and Nitrogen Fertilizer on ''Irwin'' Mango (Mangifera indica L. cv. Irwin) Fruit

• Main Authors: Ching Chuang, 莊淨
• Other Authors: Ching-Chang Shiesh
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/59770043167353839581

碩士 === 國立中興大學 === 園藝學系所 === 102 === In Taiwan, Mangifera indica L. cv. Irwin encounters some problems when exporting to other countries. The most serious one in marketing is the appearance of mango fruit. In recent years, ‘Irwin’ had found some trouble in turning red after maturity. The syndrome includes green fruit peel at the fruit shoulder and the pulp fails to ripe. The objectives of this study are to compare some basic maturity characters in normal mango fruit (CK) and ‘green head’ fruit (GH). In firmness test, the shoulder of GH fruit was significantly harder than CK fruit. The CK fruit showed a higher total soluble solid content compared with GH fruit. Using colorimeter to analyze fruit shoulder peel fragments. Indicated that the a* value of GH fruit is significantly lower than CK fruit, representing the fruit peel is more green. Analysis of ethylene release rate showed that GH fruit had a lower rate than CK fruit, and no significant difference in respiration rate can be observed between CK and GH fruit. In order to investigate the cause of green head, urea was used to induce this symptom. During the fruit development period, urea was sprayed and fertilized once a week with 1000 ppm on the whole mango tree and 5 kg for each tree for three weeks. At the fourth week and fruits matured, samples were taken and analyzed. Results indicated that firmness and total soluble sugar are significantly decrease between treatment and control groups. And the color at fruit shoulder did not appear greening in treatment group. As well as the nitrogen element did not show difference between treatment and control groups. Thus we can inferred that nitrogen overdose may not be the reason causing “Green-head” in mango fruit.