Saccharomyces cetsvisiee mutants selectee after EMS treatments WAre
evaluated for their efficiency In improving growth, nutritional status of Irees, praoarvest
frull drop percentage, yield and quality 01 Valencia orange fruits. Mutants were
selected according to their proline accumulation 3nd osrnotorerance in the presence of
a solution of high osmolarity (1 M NaCI). Two mutants, which were more
osmotoleranl and had approximately 10 tlrnas more proline than the original strain,
wet« selected for foliar spraying of vatencia orange trees al 0 concentration of I ml (4
X 10^' cells)/L. The experimental trtals were conducted three Umes during 2001/2002
and 200212003 in a private farm In ouwesoa. EI·Menofey8 Govemorate, Egypt
Results showed a remarkable Improvemenl In leal area, leaves minerat content,
preharvest fruit drop percentage and yield. Physical and chemical propl:)rti~s of Iruits
were also enhanced in both harvest dales, Quality 01 (lull espectauv vita min C and
amino acid contents were also Increased, II could be recommended for foliar spraying
by yeast mutants especially for exporting vstencra orange fruits.