محمد عبداللهیان نوقابی

Drought stress is one of the main reasons for the reduction of quantitative and qualitative yield in sugar beet cultivation, on the other hand, the increasing reduction in available water, especially in arid and semi-arid regions, has made the worse situation. In this situation, the use of drought-resistant cultivars is an effective way to reduce production risk. For this purpose, experiments were conducted in the form of split plots in based of RCBD statistical design with the main factor of irrigation (90 and 180 mm) and sub-genotype factor (16 hybrids and 4 genotype control varieties) in the years 2016 and 2017 at Karaj Sugar Beet Research Institute. The results showed that there is a decreasing trend in the average root yield and white sugar yield in two years under stress conditions of 28.5 and 10.5%, respectively, compared to normal irrigation conditions. However, under stress conditions, sugar content had an increasing trend, and root impurity values (sodium and nitrogen) had a decreasing trend, which was accompanied by the highest values of the sugar extraction coefficient. Also, the reduction of water consumption in stressful conditions led to an increase in the efficiency of irrigation water in stressful conditions compared to normal. In the examination of genotypes, based on two indices of tolerance and resistance to drought stress and yield index, genotypes number 1, 3, 9, 12, and 16 were identified as promising genotypes.

Estimation of sucrose content in sugar beet through density determination is notable in terms of its non-destructiveness, inexpensive, speed and lack of destructive environmental effects compared with polarimetric method. The aim of this study was to evaluate the effect of sugar beet root weight on sucrose estimation by densitometry compared with polarimetry method. One hundred fifty healthy sugar beet roots cultivated in the field and harvested in Karaj, Iran were randomly selected. Each root was considered as an experimental sample. Brei was prepared from the root samples after weighing and density determination. Qualitative characteristics included sucrose, dry matter, marc, and soluble solids. Identification of outliers’ data was performed by standardization of residues. Samples were divided up into 13 weight classes in 100 g groups and then a linear relationship between density and sucrose was determined for each class. Statistical comparison between slope and intercept of linear relationships was performed in a stepwise manner from the smallest to the highest weight class and if there was no significant difference (P> 0.05) data were placed in a statistical group. Results showed that average sugar content, dry matter, marc, and purity of the samples were 15.10, 23.46, 4.06, and 73.84%, respectively. The coefficient of determination (R2) obtained from the linear relationship between density and sucrose in weight classes decreased with increasing root weight so that R2 = 0.997 for roots smaller than 350 g and R2 = 0.67 for roots larger than 1450 g was obtained. Statistical comparison of slope and intercept width regression coefficients from the origin of linear relationships between density (x) and sucrose (y) in weight classes resulting in three classes with a weight range of <350-750 g (small) including linear relationship y = 43.38x-32.557 and R2 = 0.92, medium weight class with weight range of 751 to 950 g (average) with linear relationship y = 51.55x-41.38 and R2 = 0.89 and weight class of 951 to roots larger than 1450 g (large) with linear relationship y = 58.05 x-48.014 and R2 = 0.77. Therefore, considering the root weight, the linear relationships obtained by density determination can be used instead of polarimetric method to accelerate the estimation of sucrose content.

In order to evaluate quantitative and qualitative properties of three sugar beet cultivars (HI1059, Palma and Merac), an experiment was conducted as randomized complete block design with four replications at Agricultural Research Center Safiabad in 2011-2012 and 2012-2013 growing seasons. The analysis of simple variance examined showed that in first year among varieties for the bolting, sugar content, alkalinity and white sugar content traits there significant difference, whereas in the second year of potassium, molasses sugar and white sugar content traits were significant differences. The result of the compound analysis in both years the effect year on bolting, sodium, potassium, amino-nitrogen, molasses sugar, white sugar content and extraction coefficient of sugar traits was significant. The result mean bolting (%) in the first year showed that in the HI1059 and Palma cultivars were 32.6% and 51.4%, respectively and in cultivar Merac, did not bolting happen, Whereas in the second year due to the weather moderation and absence of long cold any of the cultivars did not bolt. HI1059 cultivar of the most traits was higher than other cultivars. Depending on the climatic conditions experiment and the cultivation of sugar beet cultivar, there was differences in the number of plants bolting and the degree of their impact on formation and sugar molasses.

In this research, the ability of the reflectance near-infrared (NIR) spectrometry was investigated for non-destructive assessment of the sugar content of sugar beet roots. To this end, spectrometry of 120 samples of sugar beet was performed in the interactance measurement mode within the spectral range of 350-2500 nm using a contact probe. Spectral data obtained from the spectrophotometer included unwanted information and noise in addition to the information about the samples. In order to arrive at accurate analytical models, pre-processing of the spectral data was required prior to regression model simulation. For this purpose, multivariate calibration models of partial least squares (PLS) were developed based on the reference measurements and the information of the preprocessed spectra. A combination of different methods for assessment and prediction of sugar content was employed: smoothing, normalizing as well as increasing the spectral resolution. Prediction of the sugar content of intact samples with the PLS model based on SG D2, had the best discrimination ability. Thus, SG preprocessing (R_C^2=0.973, RMSEC = 0.306, R_P^2= 0.977, RMSEP = 0.265) is suitable for predicting beet root sugar content with high accuracy (SDR= 6.660).

To evaluate the effect of heat stress on three commercial sugar beet cultivars (Aria, Rosaflor and Paya), two experiments were conducted in laboratory (20-44°C; at germination stage) and greenhouse (30°C; at seedling establishment stage) in factorial layout, based on completely randomized design in Sugar Beet Seed Institute, Karaj, Iran, in 2015 and 2016. Severe loss of germination of sugar beet cultivars was obtained at 32°C, and at 38°C, no any normal germination observed. The maximum germination percentage of Rosaflor and Aria cultivars obtained at 20°C, while that of Paya obtained at 26°C. Paya and Aria cultivars had the lowest (41%) and the highest (65%) decrease in germination at 32°C, respectively, in comparison to their maximum germinations. In greenhouse experiment, principal component analysis showed that Rosaflor performed better than other cultivars regarding to; photochemical efficiency of PSII (Fv/Fm), total dry weight, SPAD value and seedling emergence, while Paya cultivar was superior regarding to; leaf area, total fresh weight, stomatal conductance, leaf area ratio (LAR), specific leaf area (SLA) and leaf temperature depression. No significant difference was observed among sugar beet cultivars in leaf area and photochemical efficiency of PSII (Fv/Fm) traits. Paya cultivar had higher fresh weight, leaf area and stomatal conductance which led to more decline in leaf temperature through higher transpiration rate. The highest dry weight belonged to Rosaflor cultivar. According to results of laboratory and greenhouse experiments, it seems that Rosaflor and Paya cultivars were more tolerant to heat stress at early growth stage compared to Aria cultivar.

In order to evaluate the role of mulch of cover crop (barley) in two systems of, seedbed preparation in autumn and in spring, on weed biomass and qualitative and quantitative yield of sugar beet, a strip split plot experiment based on randomized complete block design with four replications was conducted in Karaj (2012-13 & 2013-14). The treatments consisted of five different seedbed preparation and barley mulch including sole cropping in autumn (b1), barley mulch applied in furrow in autumn-sowing (b2) and both in furrow and hill (b3), sole cropping in spring (b4), and barley mulch applied in furrow in spring-sown sugar beet cropping. Individual plots included 8 rows with a length and width of 25 and 4 m, respectively. Each row was divided into three parts comprising sole cropping at the beginning (hand weeding, w1), weed infested control at the middle (no weed control over the growing season, w2), and chemical control at the end (using selective herbicides). Green and cover crop biomass in autumn seedbed preparation were immediately dried by Paraquat herbicide application and were incorporated to the soil, but for spring seedbed treatments, selective herbicide was used. The results of combined analysis traits showed that the competition of natural weeds of the field significantly affected root yield, sugar yield and white sugar yield. The reduction of more than 50% of root yield (32.12 t/ha), sugar yield (4.75 t/ha) and white sugar yield (3.63 t/ha) in the infested weed control treatment compared to the weed free showed a high potential damage of weeds in sugar beet fields. In the seedbed system in autumn, which sugar beet seed was drilled directly in spring, the addition of barley to become mulch reduced root yield by 13% in the fall row method and 19% in the fall method compared to the control treatment preparation of seed bed in autumn without barley (with root yield 57.55 t / ha). Considering no significant difference between sole cropping in spring (spring control) with low tillage of sole cropping in autumn (autumn control) for quantitive and qualitative yield of sugar beet suggests that by preparing the seedbed in the autumn, it is possible for early drilling sugar beet and make optimal use of the potential of the area.

To study the possibility of integrated chemical and non-chemical methods for weeds management in sugar beet, field experiments were conducted in research station of Iranian Research Institute of Plant Protection, Meshkindasht, Karaj, Iran, in 2009 and 2010. Split-split plot arrangement in randomized complete block design with four replications was used. Experimental treatments consisted of three sugar beet planting patterns (including: single rows evenly spaced 50 and 60 cm apart and twin rows spaced 60 cm apart) in main plots, mechanical weed removal stages (in 4-6, 10-12 and 14-16 sugar beet leaf stages) as sub plots and herbicides (including: application of Metamitron and Triflusulfuron-methyl) in sub-sub plots. Only experimental error of total weed biomass and sugar beet root yield were homegeniuos, therefore combined analysis of variance was performed for these two traits. Results showed that single rows spaced 50 cm apart and twin rows had similar weed biomass. The best time for mechanical weed control was 4-6 sugar beet leaf stages, and was more effective when Metamitron was applied in twin rows. Weed removal time had significant effect on sugar beet root yield and higher root yield (37.5 ton.ha-1) was obtained when weeds removed in 2-4 sugar beet leaf stages.

This experiment was conducted during 2009-2010 in Kangavar, Iran, to study the effect of seedbed preparation time and weed management method on sugar beet yield quality and weed population. The experimental design was split plot in the form of a randomized complete block design with four replications. The main factor was seedbed preparation time (A) in three levels (a1- Seedbed preparation in the fall with barley, a2- Seedbed preparation in the fall without barley and a3- Seedbed preparation in spring). The sub factors were weed management methods (B) in three levels (a1- Integrated weed management, a2- Chemical weed control and a3- Weedy check). The results showed that weed biomass was significantly affected by seedbed preparation time. Before sugar beet drilling, weed dry weight of seedbed preparation in spring was 2 fold of seedbed preparation in the fall. The seedbed preparation treatment in the fall with barley as mulch caused 28% reduction in weed biomass and consequently 16% increase in root yield of sugar beet. Integrated weed management was more affective (85%) than that of chemical weed control (70%). The analysis of variance (ANOVA) indicated that seedbed preparation time significantly affected root yield. The highest root yield (64 t ha-1) was achieved in the fall seedbed without barley and the lowest root yield (54 t ha-1) was recorded in spring seedbed preparation time. The ANOVA showed that main effect of weed management method was significant (P<0.01) for root, sugar and white sugar yield of sugar beet. The highest root yield (73 t ha-1) was achieved in the integrated weed management treatment and weed infested control had the lowest root yield (35 t ha-1). There was no significant difference between root yield of sugar beet in chemical weed control (71 t ha-1) and that of integrated weed management treatment. Therefore, preparing the seedbed fully in the fall and drilling sugar beet in the first possible time in spring, and applying the suitable weed management method, it is possible to increase yield and quality of sugar beet. In this system, soil water may be save due to reducing tillage and also there is a chance for early drilling sugar beet in the spring.

The objective of this experiment was to evaluate technological properties of two sugar beet cultivars (HI1059 and Palma) under conditions of bolted and non-bolted plants. The experimental design was randomized complete block design (RCBD) with four replications and was carried outat Safiabad Research Center, Dezful, Iran, in 2011-2012 growing seasons. At harvest, bolted and non-bolted plants of each plot were separated. Sugar content, concentration of impurities (potassium, sodium and amino-nitrogen), molasses sugar, root yield, sugar yield, cutting resistance of rootand vascular tissue to parenchyma tissue ratio traits were measured using standard methods. In general, mean bolting (%) in HI1059 and Palma cultivars were 33% and 51, respectively. Analysis of variance showed that the experimental treatments effect for yield and quality traits of sugar beet was not significant. Results of group comparison between bolted and non-boltedplants in both varieties showed that sugar content reduced from 16.1 to 15.6% on HI1059 variety and from 16.4 to 15.9% in Palma cultivar, respectively, due to bolting. Despite the slight decrease in root yield (5%), and sugar yield (7%) in bolted plants, these reductions were not significant. Similarly, despite a slight increase in concentration of impurities, molasses sugar, energy for cutting root andvascular tissue to parenchyma tissue ratio in bolted plants, differences were not-significant. Although bolting appeared about one month before harvesting in the two sugar beet cultivars, but it had no significant effect on yield and quality of sugar beet. However, bolting causes some disturbs sugar beet harvesting and creates physical and chemical problems in the process of sugar extraction in the factory. Further research of variety trails over growing seasons may provide more knowledge regarding theeffect of bolting on yield and technical quality of sugar beet.

Near infrared reflectance spectroscopy (NIRS) is a nondestructive and rapid technique applied increasingly for food quality evaluation in recent years. In this research optical method based on near-infrared spectroscopy (900-1600 nm) has been used to determine sugar content in sugar beet. A total of 120 samples were used for the modeling، whereas 80 samples were used for the calibration set and 40 samples were used for prediction set. Four pre-processing methods، including average smoothing، multiplicative scatter correction (MSC)، first and second derivatives، were applied to improve the predictive ability of the models. Then models were developed by partial least squares (PLS). The correlation coefficient (r) and root mean square error of prediction (RMSEP) were 0. 84 and 1. 8 for SC، whereas 0. 95 and 1. 7 for SSC، respectively. The results show that NIR can be used as a rapid method to determine soluble solid content and sucrose in sugar beet.

This study aimed to modify the current purchase formula of sugar beet into a formula with different coefficients with respect to sugar percentage of autumn sugar beet. Ahvaz sugar factory was selected as an autumn sowing factory in Iran and 163 samples were randomly taken at different delivery times in 2007 (28th April to 27th June). From each truck, one sample was taken and sugar content, water content, marc, brix, reducing sugar, sodium, potassium, amino nitrogen, molasses sugars, and extraction coefficient of sugar were determined. Simultaneouly, results of all 4084 delivery samples during the campaign of the factory including 68801 tons beet belonging to three agro-industry companies and two contractors as well as Safiabad Agriculture Research Center, were statistically analyzed for sugar content (SC), soil tare, sugar beet price per tone and the paid price per vehicle. Results showed that average sugar content for all delivery vehicles was 12.84% (in the range of 10 to 15.20%) with standard deviation (SD) of 0.847. Average sugar content of Ahvaz factory was 3 units lower than the base price (16%) and 5.5 units lower than the average SC of the country in 2007 (18.29%). Average soil tare of the delivery vehicles (estimated visually) was 11.92% (in the range of 2 to 50%) with SD of 6.613. The average soil tare of Ahvaz factory was nine units greater than the country’s average in 2007 (about 3% for 4,282,805 tones of beets). Quality analysis, results showed that the average moisture content of delivery beets from autumn sowing in Khozestan province was 79% which was 4% higher than normal beet (75% moisture content or 25% dry matter). According to the results of this research and considering the potential of the region and with the aim at increasing the sugar content of the autum sowing sugar beet in Khoozestan, new formula for purchase price with three different coefficients was introduced for SC in the range of 10 to 24%. In this formula, the purchase price for each ton can be calculated by the following equations: a) SC of 10 to 15% {base price × (((SC×12) – 80))/100}, b) higher than 15 and equal to 20% {base price × ((SC×0.065) + 0.025)} and c) SC greater than 20% {base price × 1.325} and compared and analysed with the current formula assuming two units increase in sugar content. Application of the new formula with different coefficients with respect to SC is an important step in purchasing sugar beet based on quality, increasing the average SC of the region and consequently increasing the efficiency of the factory. So, this will support the farmers who are looking for the high quality sugar beet.

Crossing of pollinators and single crosses carrying RZ1 gene resulted in 44 sugar beet hybrids which were evaluated in infected fields in Fars and Khorasan. The seed of six diploid resistant pollinators and seven single crosses were first planted as parents in stekling field. After vernalization، parents were crossed in isolate tents، and hybrid seeds were harvested from female plants. The new hybrids along with resistant and susceptible checks were evaluated in infected condition during 2008-2009. According to the cluster analysis of the two year evaluation for yield، quality and disease severity index، the hybrids (7112*sb36) * 26388، (231*SB36) *26388، (436*SB36) *26388، (419*SB36) *27645، (231*SB36) *27645) and (419*SB36) *26388 were grouped with resistant checks. It seems that selection in the pollinators 26388 and 27645 will result in better hybrids.

In process of sucrose determination in sugar beet، pulp analysis by polarometric method is done on the basis of fresh root weight. The volume of the juice of 26 grams of the pulp is considered 23 ml that with 177 ml of clarifying agent would be 200 ml. Drought stress and dehydrated root reduce. The volume of the pulp extract of 23 ml. The objective of this experiment was to determine the proper method for juice extraction from beet roots grown under drought، salinity and normal conditions in the procedure of sugar content measurement. Sugar beet roots produced under various conditions were subjected to dehydration after harvest. Three levels of dehydration [(A) including fresh beet with 76±1 percent moisture (a1)، dehydrated roots up to 70± 1 (a2) and 63± 1 (a3) percent water content] and three juice extraction methods [(traditional cold digestion (b1)، hot digestion (b2) and improved French method (b3)] were arranged in a factorial experiment (3*3) in CRD with 12 replications. Sugar content، dry matter، marc، brix and juice electrical conductivity were determined for all treatments. The results showed that beet dehydration from 76 to 68 percent increased both dry matter and marc contents from 24 to 32 and from 4. 7 to 7. 1 percent، respectively. In normal roots there was no significant difference in terms of sugar content determination by various extraction methods. However، sugar content of beet roots grown under semi-salinity (P)

A field experiment was conducted to study the spatial relationships between weed seed bank and population and their distribution models in sugar beet crop (Beta vulgaris) in 2009 at Motahari Agricultural Research Station of Karaj. Sampling from seed bank before sugar beet drilling and weed population in three stages during the growing season were done using square (50*50 cm) and rectangle (25*100 cm) frameworks. Seed and plant frequency of each weed species were recorded in the both frameworks. Geostatistics technique was used to investigate the local structure of the weeds and dynamic of the spots. Amaranth, lambsquarter and narrow-leaf weeds were the prevalent weed species in the field. Semi-variogram analysis showed a range of influence from 0.24 to 141.9 m depending on weed species and sampling stage. The highest range of influence belonged to amaranth, especially in the second stage of seedling sampling. Lambsquarter had a lowest range of influence between all weeds. The highest nugget effect (1.671 and 1.308) was observed for amaranth (at second sampling from seedlings) and narrow leaf-weeds (at the first sampling from seedlings), respectively. This led to weak local correlation for amaranth and narrow-leaf weeds. Strong local correlation was recorded for seed and seedling of lambsquarter at all sampling stages. Spot distribution of weeds was confirmed by local distribution maps. Spots structure changed during the growing season. Results suggested that weed local distribution could improve management decisions and comprehension of dynamic of weeds populations.

In order to evaluate efficiency of nitrogen fertilizers consumption in a sugar beet monogerm hybrid variety of Zarghan, a field experiment was conducted in a loamy soil during 2007 in the research farm of Sugar Beet Seed Institute located in Karaj. Five levels of nitrogen fertilizers including 0 (check), 120, 160, 200 and 240 Kg/ha of net nitrogen from urea fertilizer (46 percent of pure nitrogen) and three levels of phosphor including 0 (check), 50 and 100 Kg of P2O5 per hectare from the triple super phosphate were arranged in a factorial experiment (5×3) in a randomized complete block design with four replications. The results showed that the effect of nitrogen application was significant for nitrogen uptake of both top and root parts of sugar beet, and also for nitrogen uptake efficiency of whole crop. However, nitrogen uptake of sugar beet was not affected by phosphor fertilizer and by the interaction of nitrogen × phosphor application. The highest nitrogen uptake by whole crop in this experiment was equal to 447 Kg ha-1 from the treatment of 240 Kg ha-1 nitrogen application. In the check treatment, nitrogen uptake by whole crop was 250 Kg ha-1. In Zarghan sugar beet variety, for one t ha-1 beet root production about 4 Kg nitrogen was used and from the total nitrogen uptake by whole crop, 44% was allocated in the top part and 56% in the storage root of sugar beet. There was no significant difference between the treatments for nitrogen uptake efficiency, whereas nitrogen utilization efficiency for sugar yield in the treatment of N0P0 was 35% greater than that in the treatment of 240 Kg ha-1 nitrogen application. On average, nitrogen utilization efficiency was equal to 40 Kg sugar for each Kg of N uptake by the crop. Thus, for the production of sugar beet close to actual yield potential it is necessary to consider 5 Kg of N for each t of beet root. Consequently, in order to prevent the environmental pollution, improve nitrogen efficiency, and taking into account the best quality and quantity of sugar beet yield, nitrogen application must be recommended based on the soil analysis and expected root yield and quality of sugar beet.

Prediction of seasonal weed seedling emergence patterns is useful in weed management programs. This study was carried out in research fields of Islamic Azad University – Karaj Branch in 2009-2010. Five crop fields were chosen including: barley, sugar beet and three wheat fields and in each fields between 3 to 5 sites selected randomly. Three quadrates were fixed in each sites for studying weeds emergence. Weeds emergence was weekly measured during growth season. Three models including logistic, gompertz, and weibull, were used to describe weed seedling emergence against thermal time. Gompertz model showed the best fit to data. Flix weed emergence in barely field started after receiving 5 GDD and reached maximum emergence after 190 GDD. Also in wheat fields with similar canopy, weed seedling emergence started in the same time. Although weed seedling emergence in these fields was started in 60 GDD and reached maximum emergence after 260 GDD, however weed seedling emergence of common Lambs quartes in wheat fields didn’t show similar patterns. In conclusion, growth rate of common lambs quartes increased to the maximum rate with receiving less GDD in compare to flixweed. This phenomenon may be related to their different phonological characteristics of two weeds.

In order to use chlorophyll meter (SPAD) to recognize nitrogen deficiency in sugar beet plants and used to predict the appropriate timing for fertilizer top-dressing in sugar beet a research was conducted using various levels of nitrogen fertilizer during different growth stages of sugar beet plants in the research farm of Sugar Beet Seed Institute located in Karaj during 2007, using a split plot design in time based on Randomized Complete Blocks in four replications. Five level of pre-sowing nitrogen from the source of urea was applied in amounts of 0(as control), 120, 160, 200 and 240 kg/h considered as main plots and plant growth stages as sub plots. Chlorophyll concentration in 5th leaf blade was measured by chlorophyll meter (SPAD) at five growth stages based on the number of leaves on sugar beet plants including (GS1:3-6, GS2: 6-12, GS3:12-15, GS4:15-18, GS5:18-20) leaves of each plot. In the same leaves, concentrations of nitrogen (by Kjeldahl method) and chlorophyll a, b and a (by Spectrophotometer) were measured. Results from regression analysis on the leaf number 5 showed that there was higest significant correlation between chlorophyll reading and nitrogen on a leaf area basis and on a dry-weight basis, and total nitrogen and concentration of chlorophyll (a, ab) in 12- 15 leave stage. Also results of this experiment showed that the chlorophyll meter reading were influenced by the growth stage and sampling time and the level of used nitrogen fertilizer. Nitrogen fertilizer and different growth stage had significant effect on the chlorophyll meter reading. The least number read from SPAD was 34 in 3-6 leaf stage, which associated with no-applied nitrogen treatment. Threshhold of chlorophyll meter was estimated 39/1 in this study in 12-15 leave stage, this threshold can be used as a criteria to compare. According to the obtained results, chlorophyll meter can be used as a simple, rapid and non-destructive instrument to determin chlorophyll concentrations in a leaf during 12-15 leaf stage and to recognize nitrogen deficiency in sugar beet plants and can be used to predict the appropriate timing for fertilizer top-dressing after of calibiration for region in sugar beet.

Effect of split application of nitrogen fertilizer and harvest ime on the root yield and quality characteristics of sugar beet cv 7233 was studied under sprinkler irrigation system in Juvein Plain, Sbzavar, Iran. Five levels of split applications of nitrogen (N1: 25% at planting + 75% at thinning time, N2: 50% at planting + 50% at thinning time, N3: 25% at planting + 50% at thinning time + 25% at 20 days after thinning, N4: 100% at thinning time, and N5: 50% at thinning time + 50% at 20 days after thinning) were assigned to the main plots. Four harvest times (from late August to late November with one-month intervals) were randomized in sub plots as split plot arrangement in randomized complete block design with four replications in three years (1998-2000). Combined ANOVA showed that the effect of split application of nitrogen on root yield and quality characteristics of sugar beet was not significant. Harvest time had significant effect on all sugar beet traits, except root impurities. There was no significant effect of split application of nitrogen×harvest time on plant characteristics. Delay in harvest time increased root yield and white sugar yield from 40 and 3.9 t ha-1 in the first harvest (late August) to 68 and 8.27 t ha-1, in last harvest (late November), respectively. Sugar content also increased from 12.8% in the first harvest to 15.2% in last harvest. In conclusion, it may be suggested that sugar beet in the Juvein region is harvested from late October and whole nitrogen fertilizer is applied after sugar beet thinning at 4-6 leaf stage under sprinkler irrigation system.

Cellulose is a raw material which is extensively used in the manufacture of paints, papers, textiles, agricultural products and cosmetics. The waste of sugar beet pulp after titration is a source of cellulose. The current study was carried out to study the possibility of cellulose production from sugar beet pulp waste at titration stage as a 3×3×2 factorial study on the basis of a Randomized Complete Block Design with three replications. So, firstly the waste of titrated sugar beet pulp was collected, washed, dried and ground. Then, the ground sample was hydrolyzed by hydrochloride acid 0.6 N at 45°C for 48 hours and was mixed with water at 70°C for one hour in order to isolate dissolved pectin and pectic compounds. Then, the remaining waste was washed, dried and treated with soda solution with the ratio of 1 g waste:100 ml soda solution at three levels with the concentrations of 2.5, 5 and 7.5% (w/v) at three lengths of soda impact including 8, 10 and 12 hours and two levels of temperature of soda impact including 24 and 45°C in order to isolate the basic medium-dissolved polysaccharides from cellulose. The measured traits included relative purity, viscosity and cellulose molecular mass. Results showed that the effect of soda concentration and stirring length as well as their interaction was significant on relative purity at 5% probability level. In addition, it was revealed that out of the studied treatments, the cellulose extracted through treating with 5% soda stirred for 12 hours at 45°C had significantly higher quality given that it enjoyed 95.2% relative purity, 15.9 mPa.s-1 viscosity and 255000 kg.mol-1 molecular mass which were significantly higher than those of other treatments. Therefore, this method allows extracting cellulose with 95.2% relative purity from sugar beet waste.

The current study was carried out to examine sugar beet growth pattern in climatic conditions of Hamedan, Iran and to recognize the factors affecting its quantity and quality as well as the physiological indices. Two sowing date experiments were conducted on the basis of a Randomized Complete Block Design with four replications and 11 harvests. The plots were destructively sampled and the growth was analyzed by regression method on the basis of the variations of leaf area index, leaf dry weight and total dry weight which are the basis of growth analysis. Results revealed that the maximum crop growth rate of the earlier sowing date reached to 20.2 and 23.3 g.m-2.d-1 90 days after planting in 2002 and 2003, respectively. In the second sowing date, maximum crop growth rate reached to 29.5 and 25.0 g.m-2.d-1 110 and 96 days after planting in 2002 and 2003, respectively. Maximum leaf area index of the earlier sowing date was obtained about three months after planting approximately concurrent with the realization of maximum crop growth rate and reached to 2.5 in 2002 and to 2.6 in 2003, but it started to slowly decrease at later growth period. Relative growth rate was the highest at the early growth period and linearly decreased during growth period. Net assimilation rate firstly increased slowly, but as the leaves grew and shaded each other, it started to decrease. The highest root growth rate in the earlier sowing date reached to 10.1 and 20.0 g.m-2.d-1 94 and 92 days after planting in 2002 and 2003, respectively. The highest root growth rate in the second sowing date reached to 14.0 and 17.3 g.m-2.d-1 108 and 95 days after planting in 2002 and 2003, respectively. In total, root potential yield was considerably higher in the earlier than in the delayed sowing date under climatic conditions of Hamedan in both years. The sugar beet growth pattern-related physiological indices were greatly consistent with crop yield potential during growing season. Therefore, given the climate changes and global warming, sugar beet sowing in the earliest possible date in Hamedan is recommended in terms of physiological indices and yield.

In order to study the reason for the prominent increase of the average of sugar content in sugar beet produced in Iran in 2007 and finding the relation of this increase with climatic parameters, Chenaran sugar factory district was chosen. Due to precise and reliable statistical data of sugar factory during the campaign and weather data, Chenaran sugar factory was chosen for this investigation. The most important climatic parameters affecting the sugar content of sugar beet (temperature, precipitation, relative humidity, sunshine hours and wind speed) as well as their changes in 2007 in comparison with the previous years were investigated. Regression analysis on the final number representing the sugar content of sugar beet produced in the factory during 2001- 2007 as dependent variable and monthly climatic parameters as the independent variables was conducted. Furthermore, the effect of climatic parameters on soil tare and sugar content of sugar beet during the campaign was analyzed. The daily data of soil tare and sugar content in Darzab district during the campaign of the sugar factory in 2007 were arranged in the form of 10-day averages which were fitted against the 10-day averages of sugar beet soil tare and sugar content and subsequently linear correlation coefficients were calculated. By using the stepwise method, the most important factors were determined. The results showed that among the climatic parameters, the most significant factor affecting sugar content was the minimum temperature in August. The decrease of minimum temperature on August is justifiable by considering the plant physiological changes. The number of days with a temperature of -4°C or less (freezing days) and relative humidity, respectively, had the highest correlation with the soil tare and sugar content in 2007. Therefore, the climatic parameters, especially the minimum temperature in August and in case of the severe increase of temperature, proper and well-timed irrigation has significant effect on sugar content. Proper planning of harvesting and delivering the sugar beet during Autumn regarding to meteorological forecasting in each zone can play a substantial role in decreasing the soil tare and increasing the sugar content of sugar beet.

This research was conducted in order to evaluate genetic diversity, and screening the tolerant genotypes of sugar beet subjected to continuous and severe water stress in the experimental farm of Sugar Beet Seed Institute (SBSI) in Karaj in 2008. The experimental design was a randomized complete block with 6 replications. Fifteen O-Types which were tolerant to drought plus 5 (check) genotypes were evaluated. Permanent and severe drought stress started by stop of irrigation after plant establishment continued to the end of growth season. The soil water suction reached to about 4 MPa in the horizon of 0-30 cm at the end of growth period. The results of ANOVA showed that the effect of genotypes on the root yield, shoot dry weight, total dry weight, root dry weight, root dry weight/ shoot dry weight ratio, sugar yield, achievable sugar yield, sugar percentage, harmful nitrogen and sugar percentage were significant (P<0.01). Genetic diversity among the new surveyed genotypes showed drought tolerance of sugar beet genotypes. The results confirmed that under the situation of permanent and severe water stress the genotypes of G8 (O-Type 7617) and G4 (O-Type 9590) were distinguished as tolerant O-Types and may be used in the breeding program for drought stress species. In the correlation analysis, white sugar yield with total dry weight and root dry weight showed the most positive correlation coefficients. Step wise liner regression analysis was carried out, showing sugar yield, white sugar content, sugar content and root yield, as independent variables, had significant effects on white sugar yield. With respect to yield and its components, the latter 4-mentioned characteristics showed high correlation among each other. The principal component analysis (PCA) showed that five components accounted for 82.08% of total variations. The UPGMA phonogram constructed on the basis of morphological data distance shows four clusters.

In the present experiment, the effects of nitrogen and phosphor fertilizer application in two methods of furrow and trickle irrigation on the yield and quality of sugar beet seed cultivar 7233 were studied. The experiment was conducted as a split factorial in a completely randomized block design with three replications during 2003 and 2004 in Hamedan province. Main plots were allocated to irrigation methods (furrow and trickle irrigation systems) and sub plots to four nitrogen levels (0, 60, 120, 180 kg/ha) and three phosphor levels (0, 30, 60 kg/ha). Yield, quality and technological particular of sugar beet seed were evaluatged. The results of combined analysis showed that total consumed water in trickle irrigation system relative to furrow irrigation decreased about 50%, however, water use efficiency in trickle irrigation was 0.59 kg/m3 and twice as much as furrow method. By increasing nitrogen in trickle irrigation relative to furrow irrigation, the highest sugar beet seed yield and sugar beet seed yield standard was achieved. In trickle irrigation, nitrogen application did not reduce significantly germination percentage of sugar beet seed. However, by increasing nitrogen level in furrow irrigation method no significant difference for germination percentage was detected. Yield seed was affected by nitrogen and also by the interaction of nitrogen × year and irrigation × phosphor × year interaction. The interaction between irrigation systems with nitrogen levels and interaction effect of irrigation × phosphor × year were significant. Seed phosphor concentration was not affected by any treatment. Seed potassium concentrations were affected by nitrogen levels and the interaction effect of phosphor and year. Sodium content of sugar beet seeds were affected by irrigation method, interaction of irrigation × year and the interaction of irrigation × nitrogen × phosphor × year. In conclusion, to produce maximum standard sugar beet seed with good germination percentage under high water use efficiency, trickle irrigation systems with application of 120 kg/ha, nitrogen fertilizer may suggest for similar conditions.

In order to study of cover crops effects on weed suppression in sugar beet, an experiment was performed in Iranian Research Institute of Plant Protection (Karaj Station), in 2007. The experiment was arranged as completely Randomized Blocks Design with four replications and seven treatments. The treatments were different cover crops (including: Wheat, barley, triticale and rye) that planted between rows. Chemical weed control, weedy and weed free plots were also used as controls. Cover crops were removed by herbicide application (paraquat at 400 g ai ha-1). Phenmedipham+ desmedipham+ethofumesat (Betanal Progress A.M, EC 27.4%) was also used in the four-leaf stage of sugar beet. Results indicated that cover crop treatments suppressed major weeds (Amaranthus retroflexus L. and Chenopodium album L.) and were similar to recommended chemical control (application of herbicide). In addition, total of weed biomass was decreased in barley, rye and control treatments. The minimum biomass of total weeds belonged to the barley+herbicide treatment. Because of synergism effects, barley+herbicide had maximum of the root and sugar yield (29.83 and 4.47 T ha-1, respectively), that was significant with other treatments. In overall, barely cover crop had the most effects on sugar concent. Therefre, sowing winter cover crops between rows for seedbed prepared in autumn (barley, rye, wheat and tritical, respectively) will suppress the dominant weeds and increase the quality and yield of sugar beet.

To investigate the effect of sugar beet leaf age and position on nitrogen content and chlorophyll meter readings (SPAD value) using chlorophyll meter in sugar beet, a field experiment was conducted in the experimental field of Sugar Beet Seed Institute (SBSI) in 2007 cropping serason, using a split-spli plot in time arrangement in RCBD with four replications. Five levels of pre-sowing nitrogen in the form of urea 0 (as control), 120, 160, 200 and 240 kg.ha-1 were assigned to main plots and five plant growth stages considred as sub plots. Chlorophyll meter readings of sugar beet leaf blade number 5, 10 and 15 were determined by chlorophyll meter (SPAD-502) at five growth stages based on the number of leaves including 3-6, 6-12, 12-15, 15-18 and 18-20 leaves of each plant. In the same leaves, concentrations of nitrogen content (Kjeldahl method) and chlorophyll a & b were measured. Analysis of variance showed that main effect of nitrogen fertilizer was significant for SPAD value (P<0.01) and nitrogen content(P<0.05). The main effect of growth stage was also significant for nitrogen content (P<0.05) and specific leaf weight (P<0.01). All measured sugar beet traits were affected by the main effect of plant growth stage. The interaction between nitrogen fertilizer × growth stage was only significant (P<0.05) for leaf nitrogen content. However, the interaction between growth stage × leaf number was significant for all measured traits of sugar beet. There was significant correlation between the SPAD value and nitrogen content of leaf, based on dry weight, in leaf nuber 5, while there was no significant correlation between the SPAD value and nitrogen content of leaf in the leaf number 10 and 15. In conclusion, chlorophyll meter reading and nitrogen content of sugar beet leaves were influenced by leaf age and position. Thus, fully expanded leaf number five may be used for chlorophyll meter reading and determination of nitrogen content in sugar beet in 12-15 leaves stages.