Trials for alleviating the problems of poor setting, uneven colouration of berries and fruit quality impaired of crimson seedless grapevines

الملخص EN

This study was carried out during 2011 and 2012 seasons to examine the effect of spraying ethrel at 300 ppm either alone or in combinations with potassin at 0.1 %, orthophosphoric acid at 0.1 %, magnesium sulphate at 0.1 %, boric acid at 0.05 % and potassium silicate (Si) at 0.05 % on alleviating yield decline, uneven berries colouration and impaired fruit quality problems in Crimson seedless grapevines grown under Minia region conditions.

Using ethrel alone had no effect on berry setting %, yield, cluster weight as well as berry weight and dimensions, while it was very effective in enhancing red berries %, T.S.S %, total sugars %, T.S.S/ acid and berries peel content of anthocyanins in relative to the check treatment.

Maturation date was also greatly advanced with ethrel treatments.

Total acidity %, percentages of pink and green berries, chlorophylls a & b and total carotenoids in the peels tended to reduce with ethrel application.

Using K, P, Mg, B or Si fertilizers along with ethrel effectively enhanced yield, berries colouration as well as physical and chemical characteristics of the berries comparing with using ethrel alone.

The promoting effect of these nutrients on yield and quality could be arranged as follows in ascending order K, P, Mg, B and Si.

Four sprays of a mixture containing potassin at 0.1 %, orthophosphoric acid at 0.1 %, magnesium sulphate at 0.1 %, boric acid at 0.05 % and potassium silicate at 0.05 % in addition to one spray of ethrel at 300 ppm applied only with the fourth spray of nutrients was responsible for improving yield quantitively and qualitatively and at the same time for reducing the problems of poor setting and uneven colouration of berries of Crimson seedless grapevines.