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Sudan Journal of Agricultural Research
Degreening
of "Hamlin" oranges
Hamid Elnil, B. Garrayl, Abu Bakar A. Abu EI Goukh, Farouk H. E Tahir2
and Gamal EI Dien A. Hamid3
Abstract:
The effect of ethrel solution on degreening of mature green fruits of "Hamlin" oranges Citrus sinensis L. Osbeck was studied. Fruits were treated with 0, 1000 and 5000ppm ethrel mixed with 100ul/1 of surfactant x78 and then stored at I5o C and 25o C and 93-95 relative humidity for two weeks.Application of 5000ppm ethrel was highly effective in inhancing degreening of fruit stored at 25oC and 93-95% relative humidity. Application of 1000ppm and 5000ppm ethrel significantly reduced the level of chlorophyll a, b and the total chlorophyll (a+b), compared to untreated fruits stored at 15oC or 25oC with 93-95% relative humidity. The reduction in the level of chlorophyll was higher in fruits treated with 5000ppm ethrel than those treated with 1000ppm ethrel. On the other hand, the reduction in chlorophyll levels was found to be significantly higher in untreated fruit stored at I5oC than those stored at 25°C. Significantly higher values of a/b ratio were noted to be associated with fruits treated with 5000ppm ethrel and stored at 25oC compared with fruits treated with I000ppm ethrel or untreated fruits which resulted in lower values of alb ratio. Negative values of alb ratios were recorded in untreated fruits stored at 15oC or 25°C. However, storing untreated fruits at 15oC resulted in very low values of a!b ratio. Fruit lightness (L-values), values of chroma (saturation index) were higher in fruits treated with 5000ppm ethrel stored at 25oC than fruits treated with 1000ppm stored at 25oC or untreated fruits stored at 15oC or 25°C. However, fruits treated with 5000ppm and stored at 25oC showed a smaller hue angle (Tan-I b/a) compared to 1000ppm ethrel and untreated fruits. Significantly lower values of chroma (saturation index) were associated with untreated fruits stored at 15°C or 25oC than fruits treated with 1000 ppm or 5000ppm ethrel and stored at 25°C. The rate of ethylene production by fruits treated with 5000ppm ethrel and stored at 25oC was significantly higher than that produced by 1000ppm ethrel-treated fruits stored at 25oC or untreated fruits stored at l5oC or 25°C. The production of Co2 was not affected by ethrel treatments.
Keywords:
Sudan Journal of Agricultural Research Vol. 3(2000) PP. 59-64
