Growing of sugar beet in the tropics and subtropics is rapidly increasing as an important component of the sugar industry. The present study was carried out at the Agricultural Research Farm of the Delta sugar Company, El-Hamoul, Kafr El-Sheikh, Egypt during the two successive growing seasons 2020/2021 and 2021/2022 to evaluate the response of sugar beet varieties to three sowing dates under four geometrical distribution-based planting densities.
The analysis of variance (ANOVA) revealed significant and highly significant effects of sowing dates, planting densities and varieties as well as their interactions on the yield and quality parameters of sugar beet, i.e., sucrose% (Pol%), Na%, K%, α-amino-N%, quality index (Qz)%, root yield (RY), recoverable sugar (RS)%, recoverable sugar yield (RSY), sugar loss (SL)% and sugar loss yield (SLY). The highest root and recoverable sugar yields were produced from the late cultivation of the variety Santoline on October 16. Early cultivation of the Steel variety on August 17 at a high planting density (80,000 plants fed-1) produced the highest values of sucrose content, RS% and Qz%, but the lowest values of Na%, K%, α-amino-N% and SL% in the two growing seasons. Whereas late sowing of the Santoline variety on October 16 at a moderate-low planting density of 53,300 plants fed-1 produced the highest RY and RSY in the two growing seasons. The results of the current study are crucial for sustainable and improved cultivation of sugar beet in Egypt.