YIELD AND TECHNOLOGICAL CHARACTERISTICS OF SOME SUGAR BEET CULTIVARS AS AFFECTED BY SOWING AND HARVESTING DATES

Two field experiments were conducted at Mallawi Agricultural Research Station, Minia Governorate in 2002/2003 and 2003/2004 seasons to Investigate the effect of sowing and harvesting dates on yield and technological characteristics of some sugar beet cultivars. Planting dates were15 September, 15 October and 15 November. The tested sugar beet cultivars were Gloira, Oscar poly, Allexa and Sofie and the harvesting dates were after 180, 195 and 210 days from sowing. Split-split plot design with three replicates was used in both seasons, where sowing dates were arranged in the main plots, harvesting dates occupied the subplots while the sub-sub plots were assigned for the tested sugar beet cultivars. The obtained results indicated significant differences in root, recoverable sugar and top yields as well as technological quality characteristics (pol. %, rendement, sugar loss %, quality index, and fiber %) as affected by the studied sugar beet cultivars, sowing and harvesting dates. The highest root and recoverable sugar yields as well as pol. %, rendement and quality index of sugar beet were achieved by sowing sugar beet on 15^th October followed by 15^th September and 15" November. Harvesting beets at age of 195 days recorded the highest values of the above mentioned traits followed by 210 and 180 days. Gloria cultivar gave the best values of the same traits followed by Oscar poly, Allexa and Sofie cultivar, respectively. Sowing Gloria and/or Oscar poly cultivars early on the 15°' of October/or September combined with harvesting sugar beet plants at age of 195 days is preferable and recommended for increasing sugar production and grower income under Middle Egypt conditions, Minia Governorate. Keywords: Sugar beet, planting date, harvesting date, cultivar, pol %, rendement and quality index.