Study of the possibility of winter sowing of sugar beet (Beta vulgaris L.) early cultivars in Moghan region, Iran

Shortage of irrigation water is the most important limiting factor in sugar beet production, therefore, winter sowing can be a suitable strategy to increase water produvtivity and production of this crop. For this purpose, 11 sugar beet early cultivars were sown in the first half of February and were studied on two different harvest dates (early and late July) at Moghan Agricultural Research Station (Iran) during three cropping seasons (2019, 2020 and 2021). Since bolting percentage in all studied sugare beet cultivars was zero, therefore, this trait was not included in the analyses. Combined analysis of variance showed that the effects of year and cultivar were significant (P≤0.01) on all the studied traits: root yield, sugar content, Na+, K+, alpha amino N, sugar yield, molasses sugar content, white sugar content, white sugar yield and extraction coefficient of sugar. The harvest time and year interaction effect was significant (P≤0.01) on all traits. Cultivar and year interaction had significant effect on all traits except root yield and molasses sugar content. Cultivar and harvest time interaction effect was only significant on K+ and white sugar yield. Mean comparisons indicated that the highest white sugar yield obtained in the second (12.60 ton.ha-1) and first (12.18 ton.ha-1) harvest time of 2021cropping season, respectively. Cv. FDIR19B3021 (14.38 ton.ha-1), cv. Dravus (14.26 ton.ha-1) and cv. SVZB2019 (14.18 ton.ha-1) had the highest white sugar yield in 2021 cropping season, respectively. Cv. FDIR19B3021 (10 ton.ha-1) and cv. Dravus (9.70 ton.ha-1) had the highest white sugar yield in the second harvest time, respectively. Considering the results of this experiment, cv. FDIR19B3021 and cv. Dravus can be recommended for winter sowing in Moghan region should the crop is harvested in late July.