مجله چغندر قند
سال سی و هفتم شماره 1 (بهار و تابستان 1400)

Rhizoctonia root rot mainly caused by Rhizoctonia solani AG 2-2 and R. solani AG-4 is a sugar beet disease in Iran. In this study, the resistance of foreign and domestic commercial cultivars, available to farmers, against both pathogenic groups of AG 2-2 and AG 4 was evaluated in greenhouse and field conditions. Under greenhouse condition, 18 cultivars were planted in pots along with a control cultivar (Jolgeh) and after 8-weeks, seedlings were inoculated with corn seeds infected with R. solani AG 2-2 and R. solani AG 4 isolates. Six weeks after inoculation, the intensity of contamination on the roots of each plant was measured based on a nine-point scale (1 to 9). For field evaluation, cultivars were planted in a contaminated field in 50-m-long rows with three replications and the intensity of root infection was evaluated at harvest. Results showed that there was a significant difference between cultivars and susceptible control and also among cultivars in both greenhouse and field conditions. Also, the general response of cultivars to both pathogenic groups was similar. In total, Ekbatan, Iris, Aigrette, Novodoro, Ivano, Novella, Tourelle, Modex, Efesos and Cadet cultivars had the lowest infection under different trial conditions.

The aim of this study was to evaluate the effect of reducing nitrogen fertilizer application as well as foliar spray of zinc sulfat on the quality characteristics of two sugar beet cultivars in autumn cultivation. The study was conducted in a factorial design based on randomized complete block design with three replications at the Faculty of Agriculture in Lorestan University during two crop seasons (2017-19). The Experimental treatments included two autumn-sown sugar beet cultivars (Chimene and Rosagold) and four fertilizer levels including F1: 138 kg ha-1 nitrogen (control), F2: 124 kg ha-1 nitrogen and foliar spray of zinc sulfate, F3: application of 110 kg ha-1 nitrogen and foliar spray of zinc sulfate, F4: 96.6 kg ha-1 nitrogen and foliar spray of zinc sulfate at a rate of 5/1000. The highest root yield (90.15 t ha-1) belonged to Rosagold cultivar and among the treatments, the highest root yield was related to F2 treatment. The highest sugar content (16.15%) was obtained in 20% reduction in nitrogen application and foliar spray of zinc sulfate. Also, the highest white sugar content (15.57%) was obtained from Rosagold cultivar in 20% reduction in N fertilizer application and foliar spray of zinc sulfate, which showed 26.17% increase compared with control treatment (F1). The highest molasses sugar and Na, K and α- N as 2.7, 2.61, 7.90 and 2.90 meq 100 gr beet-1, respectively was observed in Chimene. Also, the highest bolting percentage was obtained in Chimene and the application of 300 kg ha-1 nitrogen. According to the results of this study, it can be concluded that autumn cultivation of sugar beet using Rosagold cultivar is possible in Khorramabad region and foliar spray of zinc sulfate can compensate the reduction of nitrogen consumption by 20% without reducing the quantity and quality of autumn sugar beet.

Two separate trials were conducted as a factorial design based on randomized complete block design with three replications at the Shahid Moghbeli Agricultural Research Center in Jiroft, Iran in two cropping seasons (2016-17 and 2017-18). In the first trial, the effects of planting method including direct planting and transplanting on different sugar beet cultivars including Palma, Sharif, and Merak were evaluated, and then in the second trial, among studied cultivars, a high yield cultivar (Merak) was selected. Also, the effect of irrigation time (based on 50, 70, and 90% of water requirement) and planting methods on its quantitative and qualitative yield were evaluated. In the first trial, the highest root dry matter, extraction coefficient of sugar, sugar content, root weight, root length, fresh leaf weight, root yield and sugar yield were obtained for Merak cultivar and transplanting. The result of the second trial showed that the irrigation time based on 70% of water requirement led to the highest root and sugar yield along with a significant improvement in water use efficiency. In addition, as transplanting improved root yield and sugar yield, therefore, transplanting method with irrigation at the time of 70% of water requirement is recommended to obtain optimal root yield and sugar yield.

Decreasing of water consumption, chemical inputs, production cost and risk are among the most important advantages of transplanting method. The aim of this study was to compare the transplanting and direct seeding methods in sugar beet. For this purpose, root transplanting along with direct seeding were performed in the farmer’s field in Hamedan in 2018. Sugar beet transplants were prepared in planting stock in April and transplanted to the main field in June. Direct seeding of sugar beet was performed in the main field in mid of May. During the growing season, necessary notes were taken and at the end of the season, root sampling was performed. After harvest, two planting systems were evaluated in terms of quantitative, qualitative and economic characteristics. Root transplanting system caused an increase in root yield and sugar yield by 15 and 47%, respectively compared with direct seeding system. Water consumption under root transplanting was 10080 m3 ha-1 which was about 18% less than direct seeding. In terms of water use efficiency, root transplanting method with an efficiency of 9.66 kg root m-3 was about 40% more than direct seeding method (6.90 kg root m-3). The economic evaluation of two planting methods also showed that the increase in net income by changing planting pattern from conventional to root transplanting system was higher. In general, results showed that root transplanting system had higher quantitative and qualitative yield and economical income compared with direct seeding method.

In this study, the effects of plastic mulch and paclobutrazol on bolting, yield and quality of autumn-sown sugar beet was studied in a split plot design based on randomized complete block design with four replications in Mashhad during two cropping seasons (2018-19 and 2019-20). Planting dates at three levels (10th, 20th and 30th of October) were allocated to main plots and bolting control at four levels (control, plastic mulch, paclobutrazol, and simultaneous application of paclobutrazol and plastic mulch) to subplots. The average reduction of bolting in plastic mulch, paclobutrazol, and simultaneous application of paclobutrazole and plastic mulch compared with control was 69.06, 32.98 and 91.88%, respectively. The treatments of plastic mulch, paclobutrazol, and simultaneous application of paclobutrazol and plastic mulch increased white sugar yield by 1.11, 1.93, and 1.19 t ha-1, respectively. There was no significant difference between different planting dates in terms of white sugar yield which could be due to the bolting occurrence in early planting and as a result reduction of sugar content and also the decrease in yield in late planting. In bolting control treatments, plastic mulch increased the yield by reducing about 70% of bolting on the second planting date compared with the first planting date. Results showed that the use of paclobutrazol and the simultaneous use of paclobutrazol and plastic mulch had a significant reduction in white sugar yield. On the other hand, due to the significant effect of the simultaneous application of paclobutrazol and plastic mulch on bolting reduction, it is necessary to conduct more studies regarding the amount and timing of paclobutrazol application to eliminate the negative effects on yield.

To evaluate the effect of zinc nano-chelate and mycorrhizae on the biochemical properties of leaf and root yield under different irrigation levels, a split-plot design based on randomized complete block design with three replications was conducted in 2019. Irrigation treatments including irrigation after 60-, 90-, and 120-mm of evaporation from class A pan were allocated to the main plots and fertilizer treatments (control, inoculation with mycorrhiza, zinc nano-chelate, and zinc nano-chelate + mycorrhiza) to the sub-plots. In this study, irrigation after 120 mm of evaporation reduced the amount of chlorophyll a (17.01%), chlorophyll b (8.09%), carotenoid content (28.78%) and superoxide enzyme inhibition (31.14%), and increased leaf flavonoid content (25.47%), compared with irrigation after 60 mm of evaporation. Among the fertilizer treatments, zinc nano-chelate + mycorrhiza treatment had the highest chlorophyll-a (9.30 mg/g fresh weight), chlorophyll b (3.84 mg/g), carotenoid content (3.94 mg/g), superoxide enzyme inhibition (33.53 percent). The interaction effect of irrigation and fertilizer in irrigation after 60 mm of evaporation along with nano-chelate zinc + mycorrhiza fertilizer treatment had the highest nitric acid radical inhibition (23.45 percent) and root yield (82.62 t/ha), and the lowest leaf proline content (0.49 mg/g), as well as leaf phenol content (34.19 mg of gallic acid/ g dry weight). In this study, application of mycorrhiza, especially under water deficit conditions, through improving biochemical properties and regulation of antioxidant enzymes activity, was able to moderate the effect of water stress on root yield and also increase root yield compared with control.

Predicting crop yield is an important factor for efficient planning and management. In the present study, a simple mathematical model is developed for predicting the yield of autumn-sown sugar beet in Khuzestan region. In this model, the logistic function was used, in which the root yield and white sugar yield is defined as a function of irrigation, rainfall and evaporation from the pan. In order to evaluate the model, data of two-year trials conducted under five treatments of drip irrigation water based on percentage of water requirement (25, 50, 75, 100 and 125%) at Safiabad Agricultural Research and Education and Natural Resources Center, Dezful, were used. Results showed that the model was able to estimate root yield and white sugar yield with good accuracy so that the normalized root mean squares error (NRMSE) for estimating root yield in the calibration and validation stage were 9.4 and 13.0%, respectively. Also, the value of NRMSE for estimating white sugar yield in both calibration and validation years was less than 10% and equal to 6.8 and 9.8%, respectively. The model is able to have good accuracy during the growing season and estimate the values of root yield and sugar yield during different days after planting (DAP) with an error of less than 20%. Considering that the model presented in the current study is an experimental model, it is recommended to first recalibrate the model, and then use it in regions with different climatic conditions.

In this study, two different methods were used to evaluate the resistance to rhizomania disease in the root and leaf of sugar beet cultivars Sharif, Dorotea, Aria, Sina, Isabella, Pirola, Ludwina and Brigitta under greenhouse condition. The cultivars' seeds were planted in both sterile (to rub-inoculation leaves) and infection soil (to evaluate infected roots). Results of analysis of variance of greenhouse and laboratory data showed a significant difference between cultivars in terms of virus concentration (based on ELISA test) and percentage of seedling root infection among cultivars; so that the susceptible cultivar Sharif with the average contamination (70.59%) had the highest virus concentration (0.93) and on the other hand, the two cultivars Pirola and Isabella with the average contamination (21.47%) had the lowest virus concentration (0.2). Mechanical inoculation of the virus on the leaves of cultivar seedlings (method 2) showed symptoms of chlorosis and necrosis on the leaves of all cultivars in 10 days post inoculation and there was no difference between resistant and susceptible cultivars. Mechanical inoculation of sugar beet leaves resulted in local symptoms independent of genotype, and it was not possible to distinguish susceptible and resistant genotypes. Therefore, the most appropriate method is to determine the concentration of this virus in the plants’ root after two months.

Determining the relative advantage of producing agricultural products in different regions is one of the important aspects of agricultural policy and planning, based on which an appropriate pattern of production and cultivation can be achieved in different regions according to the existing conditions in each region. The present study aimed to prioritize the sugar beet producing provinces in the country based on the indices of physical advantage of production and their fluctuation coefficient within the period of 1983-2019 using numerical taxonomy method. Results showed that during a period of 36 years, the provinces of South Khorasan, Khorasan Razavi and West Azerbaijan had the highest average of scale advantage index (SAI), and the highest average of efficiency advantage index (EAI) was achieved in the provinces of Kurdistan, Kermanshah and Ardabil as 2.90, 2.20, and 1.80, respectively. Based on the results of collective advantage (AAI), the provinces of West Azerbaijan, Khorasan Razavi and Isfahan with 0.10, 0.22 and 0.33 had the lowest coefficient of fluctuation of the collective index and with 1.93, 14.14 and 1.74, respectively had the highest average of collective advantage among all the provinces of the country.