Journal of Sugar Beet
Year:2008 | Volume:24 | Issue:1|Papers Count:8

For optimum utilization of saline soil and water resources, various methods have been proposed. Application of best management practices and selection of salt tolerant cultivars are two important issues. Selection and breeding for salt tolerant cultivars require potential genetic materials, screening and evaluation of them in laboratory and field experiments. Starting in 2000, 80 sugar beet genetic genotypes(Iranian Sugar Beet Seed Institute) were evaluated for salt tolerance in the greenhouse and field conditions. Each year 20 genotypes consisting of multigerm, diploid, tetrapolid, Otype and monogerm genotypes were evaluated in the greenhouse condition using split plot based on randomized complet block design with two replications, treated with 8, 16 and 24 ds/m irrigation water. The germination- rate was determined after 4 to 5 weeks and the genotypes were classified for salt tolerance. In another experiment, the genotypes were evaluated in two separate randomized complete block design with four replications, in Roudasht Agricultural Salinity Station in the field condition using 8 and 12 ds/m water for irrigation in a soil with initial ECe of 8±1 and 12±1 ds/m, respectively. At the end of growing season, traits such as root yield, sugar content, and sugar yield were determined. At the end of four years, data were pooled and the genotypes were evaluated based on Salt Stress Tolerance Index. To minimize the effect of year and environment, the relative amounts were calculated for each year yield and some quality traits. The results of greenhouse trials showed that there were significant difference for germination rate among genotyes only in 2001. Based on field experiments, there were significant differences among genotypes for root yield, sugar content and white sugar content in 8 ds/m or 12ds/m or both levels. Results showed that the most proper level for evaluating genotypes in the field conditions was 12ds/m. On the basis of STI, genotypes 9671-P.11, 9597-P.1 and OTYPE 231 for gemination, and 9669-P.24, BP KARADJ, 9671-P.10, BP MASHAD and 9597-P3 for white sugar content were evaluated as tolerant. Among them, BP MASHAD with the highest STI was the best genotype.

In order to evaluate the effects of sugar beet sowing date, planting density and cultivar on solar radiation interception, the present study was conducted in Kamal-Abad Agricultural Research Station of Sugar Beet Seed Institute (SBSI) in 2005 and 2006. The experiment arranged was in split-split plots based on Randomized Complete Block Design (RCBD) with three replications. The sowing date, planting density and cultivar were assigned to main, sub and sub-sub-plots, respectively. Results showed that the photosynthetically active radiation (PAR) rised from 8 MJ.m-2.day-1 during late April and after reaching the maximum amount (17.61-17.75 MJ.m-2.day-1) during June started to gradually decrease through growing season. Total intercepted PAR (iPAR) had significance differed significantly (P<0.01) between studied years and iPAR in 2005 (1817.04 MJ.m-2) was about 8.15% greater than that in 2004 (1680.22 MJ.m-2). The relationship between radiation interception (fi) and leaf area index (LAI) was significant in 2005 (r2=0.82**) and 2006 (r2=0.64**) indicating that increase in LAI caused the increase in iPAR. The highest fi was observed in mid-October and LAI equaled to 2.5-3.5 in Karaj. Sowing date had a significant effect (P<0.01) on fi and sowing the sugar beet in the earliest possible date increased the iPAR by 29.67%. The effect of planting density on fi was non-significant and linear correlation coefficient was positive and non-significant. Average radiation extinction coefficient (K) was estimated to be 0.605. The effect of sowng date on K was not significant. The increase in planting density from 6.0 plants.m-2 (K=0.717) to 7.5, 9.0 and 10.5 plants.m-2 reduced the K by 11.2, 18.6 and 32.9%, respectively. The significant effect of cultivar on K in 2006 showed that the K of cultivar 428 (0.373) was less than that of cultivars Jolgeh and DS4027 by 54.1 and 72.9%, respectively.

Water is one of the most important restrictive factors in crop production. Therefore, optimum use of water resources in line with sustainable agriculture is mandatory. In this research the effects of different amounts of allowed soil water depletion at various growth stages of root sugar beet and its effect on qualitative and quantitative characters of the crop were studied. The experimental design was randomized complete blocks in a factorial arrangement with 2 factors and 4 replications. The trial was conducted at Miyandoab Agricultural and Natural Resources Research Station, West Azarbaijan for 2 years (2004-2005). Growth stages of sugar beet (factor A) at four levels included the first (S1), second (S2), third (S3) and fourth (S4) growth stages. Allowed soil water depletion (factor B) at 3 levels 65-70% (I1), 85-90% water depletion (I2) and 45-50% of water depletion (Control, I3) were applied at all growth stages. Different quantitative and qualitative traits of sugar beet and the amount of the water used for each treatment were measured and recorded. The results showed that generally the different growth stages influenced qualitative characteristics of root with less effect on root yield, while water stress (different levels of water depletion) influenced qualitative both and quantitative characteristics of root. Although, water depletion caused low root yield but in some cases due to improvement of qualitative root characteristics and sugar extract, it recompensated for root yield reduction. The greatest WUE, based on root yield, and the lowest WUE belonged to S3I1 (5.42 kgm-3) and S1I2 (3.88 kgm-3) treatments, respectively. The greatest WUE, based on white sugare content, and the lowest WUE belonged to S2I3 (0.64 kg/m3) and S4I2 (0.33 kgm-3), respectively.

Sugar beet roots and attached soil are usually transferred to sugar factories for processing, then the roots are washed by pressurized water. Muddy water as waste flows in canal and is used to irrigate fields. The possibility of occurrence and fluctuations of the pathogenic organisms in waste were studied in 2005. The samples were collected from waste water once a week. Isolation of pathogens was done by a) citrus leaf baiting method and on PARPH selective medium, and common culture media such as PDA, CMA, MA, NA and WA, b) irrigation of sugar beet seedlings with waste water, c) bioassay with healthy sugar beet roots and d) cysts of nematode extracted from waste by sieves. Different pathogens were isolated from waste such as Fusarium oxysporum, Fusarium sp., Rhizopus stolonifer, Penicillium spp., Aspergillus spp., Pythium aphanidermatum Pythium sp., Phytophthora cryptogea, Ph.drechsleri, Mucor sp. Rhizoctonia solani,Geotrichum sp., Erwinia carotovora and cysts of Heterodera schachtii. Pathogencity tests were done for each pathogen. At early periods of processing, recovered populations of Pythiaceae and Erwinia carotovora were high, and in the last weeks of processing period population of Penicillium spp., Aspergillus spp., Mucor sp. and Geotrichum sp. were in high levels. Populations of Alternaria alternata، Rhizoctonia solani and Fusarium spp. were stable and cysts of Heterodera schachtii were variable during processing period. These pathogens were also isolated from fields of sugar beet irrigated with waste water.

Diseased samples with root rot symptoms were collected from different sugar beet growing areas. From rotted roots, 20 fungal isolates were identified as Fusarium solani based on morphological characteristics. Pathogenecity of the isolates was studied in in vitro condition on sugar beet roots. The results showed pathogenic variability among the isolates. Cluster analysis divided the isolates into three pathogenic, moderate pathogenic and non-pathogenic groups. In pathogenicity test on 14 week old sugar beet plants no symptoms was observed in greenhouse conditions but the symptoms appeared on exposed roots .Genetic diversity of the isolates was studied using ITS4 and ITS5 primers through PCR-RFLP. Banding patterns of the isolates divided them into three groups including isolates with a single band (550 or 600 bp.), double band (550 and 600 bp.) and triple band (500, 550, and 600). PCR products of the isolates were digested with Msp1, EcoR1 and BamH1 restriction endonucleases. The results showed that BamH1 enzyme had no restriction site. DNA patterns of the isolates digested by EcoR1 were the same among all isolates and produced double monomorphic fragments for all isolates. Digestion with Msp1 showed intraspecific genetic diversity among different isolates of F.solani. The results didn’t show any relation among pathogenecity test, geographic location and ITS-rDNA analysis of the fungal isolates.

Flea beetles of Chaetocnema tibialis (Col:, Chrysomelidae) are important pests on sugar beet in Iran. In some cases, the damages caused by this pest are so high that some part of the field should be replanted. Since most of crop losses occur from cotyledon stage until 4-leaf stage, monitoring of the population of this pest could play an important role in decreasing damage of the pest. Sticky-colored traps are used for the pest population monitoring. To study the effects of sticky traps of different colors, an experiment was conducted in a split plot design with four replications in Esfahan’ during 2002-2003. Main plot was traps color in seven levels (green, yellow, orange, red, blue, black and white) and subplot was height of traps instalation in 4 levels (0.25, 0.5, 0.75 and 1 meter). Traps’ surfaces were coated with a thin layer of insect adhesive (tangle trap) and replaced in the margin of the field in weekly intervals. In the second year of experiment, two types of yellow (lemon and saturn) were also evaluated. Data were analyzed by MSTATC statistical software and means were compared with Duncan’s multiple range test (DMRT). Results showed that more individuals were significantly captured by lemon yellow tapes installed at the height of 0.25 meter so that the condition can be used for monitoring the population of this pest.

Sugar beet is an important crop from the point of production and consumption. In this case, Fars province is one of the largest producers in Iran. The purpose of this study was to determine the effective factors on sugar beet supply. Accordingly, time series information of the crop was collected from 1990 to 2004 in Fars province and were analyzed through Nerlove partially adjustment model that is an established method to estimate supply function for agricultural products. Results indicated that the all variables were significant except sugar beet supply in the last year. Independent variables could explain 71 percent of variation of dependent variables (supply). Therefore, elasticities of function showed that elasticity of land (0.94) was more sensitive than others. According to elasticity of product price (0.52), guaranteed price policies are not just sufficient for increasing sugar beet supply. Consequently, government is able to support sugar beet producers by adapting supportive policies at macro level and investing in sugar production.

Sowing and harvesting date are the most important agronomic factors that we should pay attention to proper date selection for sowing date in order to achieve good crop establishment and to harvest date in order to achieve the best time for crop quantities and qualities ripening. Farmers intend to germinate sugar beet seed at minimum environmental temperature. Sowing date affects crop canopy development (leaf number, size and age) in relation to absorbed radiation during growing season. Sugar beet can get optimum leaf area and use solar radiation effectively and will have more yields if it is planted as soon as possible. Cold condition in spring sowing may limit germination and establishment and cause bolting. Wet soil in this sowing may prevent on time sowing and crop couldn’t use solar radiation properly in this way. Early sowing may also decrease sugar content in most regions. On the other hand, delayed sowing till May will decrease germination because of soil dehydration and crusting during seedbed preparation. So, attention to selection of proper sowing date is necessary. Results of spring sugar beet sowing experiments show that we can sow at first possible time after hard winter coldness when soil mean temperature is about 3-5 oC. Freezing damage risk will decrease in this case and also irrigation isn’t necessary because of soil moisture and first season rains but we should irrigate land for better crop establishment at the first possible time if raining doesn’t happen. Early sowing will also increase white sugar yield in most experiments and insect damages will decrease because crop is at a growth stage which is not affected by initial insect attack. Some diseases such as Curly top and Rhizomania will decrease in early sowing. Some researches showed maximum Curly top damage in early season, while white sugar yield was high. The best sowing time is between March and last April in different areas in order to achieve the highest root and white sugar yields. Sugar beet can be harvested 180-210 days after sowing in most areas of Iran. The best harvest time based on research is between last October and first November for maximum white sugar yield. The best sowing date is between September and first October for warm and autumn sowing areas in the country. In spite of bolting decrease in delayed sowing, white sugar yield decreases significantly. The best harvesting time is between May and first June in which root yield and sugar content are high but bolted varieties increase also. So, we can use bolting resistant varieties and sow them in October and harvest them at June in Khuzestan.