Abstract

Background and purpose: Autumn cultivation of sugar beet is important in terms of the optimal use of rainfall and increasing the efficiency of water consumption; besides, it is economically more useful than the spring cultivation. But due to various reasons, including climatic conditions, its autumn cultivation is faced with limitations  in Iran and many regions of the world. Therefore, to know new areas proper for autumn sugar beet cultivation would be necessary for the sustainable supply of sugar. In the arid regions of the country, it is necessary to identify new areas proper for autumn cultivation of this crop. Therefore, the aim of this research is to investigate the possibility of delayed autumn sowing of three types of sugar beet cultivars in Bushehr province and its innovation, to verify the sustainability goals and agronomic management, and to determine the sowing date and suitable cultivar for Bushehr province in the sugar supply chain.
Materials and Methods: This experiment was carried out in two private farms with different soil and water characteristics as representatives of the agricultural lands of Bushehr province. The experimental treatments include the location of the field independently on two levels (Farm No. 1 and 2) and each farm with two cultivar treatments on three levels (Palma, SBSI 061 and Sharif) and different sowing dates on two levels (November 11 and 19) as the first and second sowing dates, which were performed in 3 replications. On April 29, that is about 170 days after the first sowing date, and 162 days after the second sowing date, sampling and harvesting operations were carried out in both fields. Quantitative and qualitative yield components of sugar beet, after data normalization, were evaluated with multivariate statistical analysis and least significant pairwise comparisons using Xlstat2020 software.
Findings and discussion: The findings of the research showed that the triple interaction effects of cultivar, sowing date and the field on all components of sugar beet yield are significant. The highest root yield and white sugar yield with 111350 and 9127, kg/ha, respectively, was obtained in (Palma cultivar, sowing date  of November 11, in farm 1) and (Palma cultivar, sowing date of November11, in farm 2), and the lowest root yield and white sugar yield in the order was obtained with 47450 and 3044 kg/ha in (SBSI 061 cultivar, sowing date 11 November in field 2) and (Sharif cultivar, sowing date of  November19, in field 1). Furthermore, the highest sugar content, white sugar content and extraction coefficient of sugar were obtained respectively with (19.1, 16.9 and 88.5%) in (Palma cultivar, sowing date of November19 in field 2). The lowest amount of root impurities, including sodium and potassium, respectively 0.87 and 4.34 milliequivalents per 100 grams of root pulp, and the lowest amount of molasses sugar (1.61%) in (Palma cultivar, sowing date of November 19, in farm 2) was obtained, and the lowest amount of harmful nitrogen (0.80 milliequivalents per 100 grams of root pulp) was obtained in (Palma cultivar, sowing date of November 11, in field 2).
Conclusion: The results showed that farm No. 1, which had a type of soil and water with a suitable texture and high electrical conductivity, had a Quantitative performance, and Farm No. 2, which had a type of soil and water with lower electrical conductivity and less texture suitability, had superior quality characteristics. Despite the significance of the effect of sowing date on some investigated traits, it is not possible to state in general which sowing date is superior; thus, both sowing dates are recommended. The average yield components of the palma cultivar are justified at the soil quality levels, and the adverse phenomenon of bolting and other challenges of autumn cultivation were observed in none of them. Therefore, delayed autumn cultivation of sugar beet with a short growing period of 162 and 170 days has the possibility of being entered into the agricultural ecosystem of Bushehr province and has the potentiallity of environmental sustainability.