Response of Some Sugar Beet Varieties to Harvesting Dates and Foliar Application of Boron and Zinc in Sandy Soils

THE PRESENT investigation was carried out at the experimental farm, El-Khattara region, Fac. Agric. Zagazig University, Sharkia Governorate , Egypt during 2010/2011 and 2011/2012 seasons to investigate the effect of micronutrients (control, B , Zn and their combinations) on four sugar beet varieties (Panther and Des 9003) multigerm, also ( LP15 and Sibel ) monogerm under three harvesting dates (180, 195 and 210) days from sowing. A split-split plot design with three replications was used. Harvesting dates were allocated in the main plots, foliar applications of micronutrients were assigned in the sub plots while, sugar beet varieties were distributed in the sub- sub plots. The results revealed that delaying harvesting date from 180 to 195 and 210 days significantly increased quality parameters, i.e. sucrose, purity and extractability percentages as well as productivity traits (root and sugar yields) in the two growing seasons. The varieties significantly differed in all studieds traits in the two growing seasons. Foliar spray with B and Zn had significant effects on all studies traits in both seasons, except for root diameter (cm) in both seasons and juice purity% in 1^st season only. Sibel had the higher root yield in both seasons for all dates of harvest.This applied also to sugar exception of one of the dates of harvest in the second season. Delaying the harvesting date to 210 days after sowing compared to 180 days significantly increased yields of root and sugar (ton/ fed) in both seasons. The foliar application with B and Zn under the three harvesting dates insignificantly affected all traits studied.