Hasat öncesi maleik hidrazit ve ethephon uygulamalarının havucun muhafaza süresine etkisi
Özet
ABSTRACT Ph.D. Thesis THE EFFECT OF PREHARVEST FOLIAR SPRAYS OF MALEIC HYDRAZroE AND ETHEPHONE ONPOSTHARVEST STORAGE LIFE OF CARROTS. Rezzan KASIM Ankara University Graduate School of Natural and Applied Sciences Department of Horticulture Supervisor: Prof.Dr. Nilgün HALLORAN This study was carried out to determine the effects of preharvest sprays of maleic hydrazide (MH) and ethephone on postharvest storage life of carrot cv. Nanco Fi. In. addition residue levels of MH and the effects of MH on endogenous ethylene and abscisic acid (ABA) changes were also determined. Preharvest application of 1000, 2000, 3000 and 4000 ppm MH and 2000 and 4000 ppm ethephone were performed as at foliar spraying 15 days before harvest, 30 days before harvest and either 15 or 30 days before harvest while 500 and 1000 ppm ethephone were applied only. 15 days before harvest Harvested carrots were packed in 5 kg sized perforated, polyethylene bags and than placed into cold room set at 5°C temperature and 85 to 90% relative humidity. Weight loss (%), respiration rate (ml CO^lcgh), total soluble solids (%), sprouting degree, sprouting ratio (%), rooting degree, rooting ratio (%), endogenous and exogenous ethylene production (ppm and ml C2H4/kgh), isocoumarin formation (mg/100 g), sensory quality, MH residue level (ug/g fresh weight) and endogenous abscisic acid content (ng/g fresh weight) were determined during experiments at monthly intervals. Results showed that ethephon shouldn't be used as a sprouting and rooting inhibitor. for carrots because it reduced marketing quality. Meanwhile MH which applied 15 and 30 at 2000 ppm, 15 and 30 at 3000 ppm were found to be effective treatments for controlling rooting and partially effective in reducing sprouting. In addition, this doses of MH also reduced weight losses compared with the other treatments, but. they increased the residue over tolerable levels so that they should be carefully when they used as a sprouting and rooting inhibitor for carrots. On the other hand, it was found that preharvest foliar spray of MH had effect on endogenous ABA content and also correlations between endogenous ABA and endogenous ethylene levels in carrots 2001, 132p KeyWords: earrot, storage, maleic hydrazide, ethephone, rooting, sprouting, ABA