مجله چغندر قند
سال بیست و پنجم شماره 1 (بهار و تابستان 1388)

The purpose of this study was to compare rooting methods in tissue culture regenerated-clones in sugar beet and their adaptation to environmental conditions and determine clones ploidy stability. Two kinds of explants including shoot apex of seedlings and inflorescence stem pieces were used for preparation and propagation of the clones in media. In the next step, three rooting and adaptation methods as main plots and four genotypes as sub plots were compared using a split plot experimental design. The methods were: 1. rooting clones in in vitro culture, 2. sink rootless shoot bases into hormonal powder and 3. inducing roots in water-culture device. The plantlets derived from each method were transferred to pots in the greenhouse for the growth and adaptation. Percentage of adapted clones from each treatment was analyzed by SAS program. The results showed no significant differences between methods 1and 2 and these two methods had advantages as compared to the third method. Therefore, method 2 does not need to root from shoots in in vitro and this is resulted in saving of money (personel, media and keeping place) and time (1 to 2 months). In the other experiment, chromosome counting of the clones was performed and genetic stability was observed at ploidy level. Adapted clones were vernalized in cold room and transplanted in the field. The plants in the field produced flowering stems and setting seeds as much as kilogram as a first report.

Resistance of 11 genotypes of sugar beet to cyst nematode was evaluated in two separate greenhouse experiments in completely randomized design. In each experiment, 50 seedlings of each genotype were inoculated with 1000 nematode larves in several times. After 9 weeks, the number of cysts on each plant was counted. Data were analyzed with SAS program. The results showed that the genotypes differed significantly in number of cysts on them in both experiments. Genotypes were classified into 3 groups: resistant, moderately susceptible and susceptible based on Duncan method at  = 0.01. W-1009,W-1010 and NEMAKIL were in resistant group, while Rasoul and some other hybrids were in susceptible group. Finally, it was found that greenhouse evaluation is a simple and efficient method for screening resistant genotypes and breeding lines and it can be used for 2-3 times in one year in greenhouse conditions.

In order to investigate the relationships of some morphological traits at the early stages of three sugar beet cultivars with final yield at varying levels of water regines, a field experiment was carried out in Karaj, and Mashhad, in 2001-2003. The objective of this study was to find the relation of some morphological traits of three sugar beet genotypes (7219-P.69, BP-Karaj and 7112) during the growing season with final yield traits such as root yield (RY), sugar content (SC) and white sugar yield (WSY) where plants were subjected to severe continuous water stress, moderate stress and nonstress conditions. The experimental design was split block with three replications. The continuous water stress gradient was applied from plant establishment onwards by using a line-source sprinkler irrigation system. Soil water content at the depth of 0-100 cm were determined by TDR and the amount of water received by each treatment recorded during the growing season. Morphological characteristics such as shoot dry weight (SDW), root dry weight (RDW), total dry weight (TDW) and SDW/ RDW ratio at three growth stages and yield and quality of sugar beet at final harvest were determined by destructive sampling. Total water used in nonstress, moderate stress and continuous stress conditions were 814, 635 and 363 mm, respectively. The results showed that RY reduced from 51 t ha-1 in normal irrigation by 24% and 57% in moderate and continuous water stresses, respectively. Similarly, WSY reduced from 6.73 t ha-1 in normal irrigation condition by 26% and 59% in moderate and continuous stresses, respectively. The response of RY and WSY of beet genotypes to water stress differed when the severity of water stress was changed. Thus, the intensity of water stress is a very important factor in the evaluation of sugar beet germplasm under drought stress conditions. There was a positive correlation (r= 0.91, P< 0.01) between the number of leaves and WSY and a negative correlation (r= -0.90, P< 0.01) between WSY and specific leaf weight. In terms of root characters, there were positive correlations (r= 0.86, P< 0.01) of root length and root diameter with WSY at final harvest. There was a negative correlation (r= -0.83, P< 0.01) between shoot: root ratio and final WSY. Thus, some morphological traits of sugar beet during the early growth stage may be useful for plant breeders to predict the genotypic productivity of sugar beet in a breeding program of drought tolerant variety. However, in order to obtain conclusive results additional studies with a larger number of genotypes are required.

In order to evaluate the effects of sub soiling and irrigation level treatments on yield of sugar beet and wheat in rotation, an experiment was conducted at agricultural research station of West Azerbaijan province. The plots were arranged as a strip plot experiment in randomized complete block design with three replications. Horizontal plot (sub soiling treatment) consisted of sub soiling depth of 45 cm and no-sub soiling, and vertical plot (irrigation level treatment) included 100, 80 and 60 percents of full irrigation. The yield of wheat and sugar beet was evaluated for three years (1379- 1380). The results showed that after 3 years, sub-soiling had no- significant effect on yield of sugar beet and wheat, but the effects of first year sub-soiling on wheat yield and first and second year sub-soiling on sugar beet yield were significant. The irrigation treatments influence on yields of wheat and sugar beet were significant (α=0.01). The sub soiling improved water productivity, general and made it possible to apply deficit irrigation without yield reduction.

In order to evaluate the effect of sugar beet sowing date, planting density and cultivar on solar radiation interception, a study was conducted in Kamal-Abad Agricultural Research Station of Sugar Beet Seed Institute (SBSI) in 2005 and 2006. The experimental design was split-split plots based on Randomized Complete Block Design (RCBD) with three replications with two sowing dates as the main plot (the earliest possible date including 04-April and 22-April in 2005 and 2006 and 40 days later including 23-May and 31-May in 2005 and 2006, respectively), four plant densities as the sub-plot (6.0, 7.5, 9.0 and 10.5 plants.m-2) and three sugar beet monogerm cultivars as the sub-sub-plot (Jolgah, Hybrid 428 and DS 4027). In terms of the effect of sowing date, it was shown that sugar beet sowing in Karadj at the earlist possible date (Mid-March) compared to the sowing date delayed for 40 days only led to an increase in intercepted radiation by 425 MJ.m-2; while radiation use efficiency (RUE) for producing dry matter which was in the range of 1.43-1.48 g.m-2 MJ-1 did not differ between the two sowing dates. The increase in plant density from 6.0 to 10.5 plants.m-2 led to a non-significant increase in intercepted radiation. RUE did not show a linear response to plant density, too; while the increase in plant density led to a decrease in radiation extinction coefficient and improvement of radiation distribution in canopy. The cultivar DS 4027 had better RUE than the cultivars Jolgah and Hybrid 428 (1.85 and 1.43 g.m-2.MJ-1, respectively). The main reason for this difference was the higher RUE of DS 4027 (1.54 g.m-2.MJ-1) in producing root system than the other two cultivars (1.10 g.m-2.MJ-1). In terms of RUE in producing shoot system, there was no significant difference between Jolgah and Hybrid 428 (0.34 g.m-2.MJ-1) and DS 4027 (0.32 g.m-2.MJ-1). According to the results, it can be conclude that improving the main drawback of domestic cultivars i.e. low R/S ratio should be given priority.

The objective of the present experiment was to study the root mass and sugar losses of sugar beet during the storing beets in two methods of on-farm storage. A factorial split plot experiment with nine replications based on a completely randomized design was conducted during 2005 in the experimental fields of Sugar Beet Seed Institute (SBSI) of Iran, in Karaj. Combination of two harvest dates (early October and November) and two on-farm storage methods (small pile in the field as a check- farmer method- and recommended pile close to the field) were arranged in the main plots. Four root storage intervals of 2, 4, 6 and 8 weeks were arranged in the sub plots. About 25 sugar beet roots were placed in a plastic net bag as an experimental unit. Quality and quantity traits of beet samples were determined in all treatments using standard methods. Sugar losses and mass loss of beet samples were determined relative to each harvest date, before storing sugar beet roots. The results showed that mass loss of sugar beet in the small pile was 2.6 times greater than that stored in the recommended pile method. Storing sugar beet in the small pile until eight weeks compared to storing beet in the recommended pile method resulted in an increase in sugar content by 2.48% (mostly due to 4.6% root dehydration). However, the concentration of sucrose on dry weight basis was reduced by 2.40%. Both sugar content and root dry matter content increased significantly by increasing the duration time of sugar beet storage until six weeks. During the two first weeks of storage, both root mass and sugar losses were significantly greater than that in the later weeks of storage. Sugar losses during the two first weeks were 40% more than that of the second two weeks of beet storage. The results of storage cost of sugar beet in the recommended pile was 50625 Rials per ton of sugar beet in terms of loading from field, transporting and keeping in the on-farm storage. However, sugar losses in this method were 1072 gt-1d-1, equivalent to 5896 Rials less than that in small pile in the field (farmer method). In conclusion, if farmers have to keep the harvested beet roots in the field more than nine days (equal to 27 Respiration Degree Days, RDD), it is economic to store the beet roots according to the recommended on-farm storage. From technical quality point of view, as the high quality of beet root as a row material may reduce the sugar losses of beet processing in the factory, the sugar factories are recommended to encourage the farmers to keep the harvested roots immediately in the recommended pile by paying some bonuses to the farmers.

The purpose of this study is determining the factors affecting timeliness of machine operation at different stages of sugar beet production. Farm-level data were collected from a sample of 227 sugar beet farmer located in three major districts of Fars province of Iran: Eghleed, Marvdasht and Fasa, selected by a random sampling method during 2006. For this purpose, the Probit model was used. The results indiated that, when the intensity of demand for using facilitites and machinery services of sugar beet factories in the studied area, the intensity of cultural practices of competitive crops, and on- time non-accessibility of sugar beet farmers to production inputs increase by 1 percent then the probability of delayed machine operation in sugar beet farms increases, respectively, by 0.413, 0.192 in Eghleed by 0.122, 0.425, 0.226 in Marvdasht and by 0.060 and 0.444, 0.158 and 0.097 in Fasa. However, if liquidity of sugar beet farmers for renting machineries increases by 1 percent, then the probability of delayed machine operation in sugar beet farms in Eghleed, Marvdasht and Fasa decreases by 0.273, 0.290 and 0.301, respectively.

Agricultural prices have a high fluctuation and forecasting may help decision making effectively. The aim of this study was to forecast the nominal and real prices of sugar beet and to recognize the appropriate forecasting model. Initially the stationary of the series was tested. In order to investigate whether the series are stochastic, the nonparametric test of Vald-Wulfowitz and parametric test of Durbin-Watson were then applied. The results indicated that the nominal price of sugar beet was non stochastic and predictable while the real price series were found to be stochastic. The study period covered 1971- 2005. The Autoregressive, Moving Average, ARIMA, Single and Double Exponential Smoothing, Harmonic and ARCH were applied to forecasting sugar beet prices. Based on the lowest forecasting error criterion, the Harmonic model was selected as the best model. The prices of sugar beet forecasted by different models were at the range of 344000-396000 and 398000-448504 Rials per ton for 2004 and 2005, respectively. The sugar beet actual price for 2004 and 2005 were 387200 and 447000 Rials per ton, respectively.