کیوان فتوحی

Sugar beet cultivars, candidate to enter the Iranian trade market, must pass the value cultivation and use (VCU) test successfully. For this purpose, 29 candidate cultivars from different companies were subjected to product comparison in the form of two experiments with the same control cultivars in 2018 and 2019. The experiments were conducted in two separate experiments of 16 and 17 cultivars in four replications in the provinces of West Azarbaijan, Khorasan Razavi, Hamedan and Fars under natural infection conditions. According to the results of the tests, among the new genotypes, 7 cultivars including BTS 7715, BTS 2015 N, BTS 1930 RHC, Annamira, Annemartha, Joker and BTS 3645 RHC were introduced as superior cultivars. These cultivars had higher sugar yield and also, they had better yield stability and disease resistance compared to the other candidate cultivars.

To assess root and white sugar yield stability of 11 spring sugar beet genotypes together with three check cultivars, a field experiment was carried out using randomized complete block design with four replications in six agricultural research stations; Toroq (Mashhad), Zarghan, Khoy, Kermanshah Miandoab, and Karaj, Iran, in 2020 and 2021. Combined analysis of variance showed that genotype × environment interaction was significant (P < 0.01), and genotypes had different performance in different environmental conditions. Based on regression coefficient, deviation from regression, Shukla’s stability variance, Wrick's ecovalence, and coefficient of determination, GB-6 and GB-10 genotypes were identified with high root and white sugar yield and yield stability. Although the number of genotypes with yield stability increased by using superiority measure and coefficient of variation, three genotypes including; GB-11, GB-10, and GB-2 showed the highest yield stability for root and white sugar yield, respectively. Using GGE biplot method, GB-11, GB-10, GB-2 and GB-6 were identified with higher root and white sugar yield, than average of all genotypes, and higher yield stability, respectively. Considering the results of this research, GB-6, GB-11, GB-2, and GB-10 were identified as high-yielding genotypes with high yield stability.

Sugar beet (Beta vulgaris L.) is one of the important commercial crops that supply approximately 35% of the world’s sugar and is widely cultivated in arid and semi-arid regions. Drought is one of the most important growth restricting environmental factors for crop species in arid and semi-arid regions of the world. Crop losses resulting from abiotic stresses such as drought or salinity can reduce crop yield by as much as 50%.

to investigate the evaluation of different genotypes of sugar beet (Beta vulgaris l.) in terms of biochemical and antioxidant properties under normal conditions and water deficit conditions excrement was conducted in split-plot design based on complete random blocks with three replications in Miandoab Agricultural and Natural Resources Research Station at 2017-18 Crop seasons. Irrigation regimes at two levels, (normal Irrigation after 90 mm of evaporation and drought stress after the 10-leaf stage of sugar beet based on 200 mm of evaporation from the Class A evaporation pan) signed to the main plot, and 18 sugar beet genotypes were assigned to sub-plots. In this research root yield, coefficient of sugar extraction, Guaiacol peroxidase, Polyphenol oxidase, Superoxide dismutase, and proline content were measured. After collecting the data, the data were analyzed using SAS software version 9.1 and the comparison of the average of the studied characteristics was performed using LSD test at the probability level of five percent.

In the present study, the effect of the irrigation regime on all studied traits was significant except for the sugar extraction coefficient at the level of probability of 1%. Among the genotypes studied significant difference was observed in terms of all the studied traits, at the probability level of 1% Interaction of irrigation regime with genotypes on root yield, sugar extraction coefficient, guaiacol peroxidase, polyphenol oxidase, and proline content at 1% probability level and superoxide dismutase at 5% probability level was significant. The results showed that water deficit stress reduced root yield by 17.38% compared to normal irrigation conditions, while the content of glycol peroxidase, polyphenol oxidase, superoxide dismutase, and proline under water deficit conditions was an increase compared to normal irrigation conditions by 118.86, 82.1, 103.61 and 113.92 percent respectively. genotypes Mean comparison in terms of root yield showed that genotype No. 10 with an average of 85.77 t / ha under normal irrigation and 72.14 t / ha under water deficit stress had the highest root yield. Under normal irrigation conditions, the highest guaiacol peroxidase, polyphenol oxidase, superoxide dismutase activity, and proline content were belonged to genotypes 21, 15, 4, and 13, respectively. While underwater stress conditions, the highest values of these traits were recorded in cultivars 10, 20, 19, and 3, respectively. Based on the results of regression analysis under normal irrigation conditions, the Sugar Extraction Coefficient and proline content with the explanation of 80 percent of root yield variation were identified as the most important traits. Based on the results of path analysis, the two traits, directly and indirectly, showed a positive effect on root yield. Underwater deficit stress proline content, guaiacol peroxidase, and superoxide dismutase with 66.3% explanation of changes in root yield Were identified as the most effective traits on root yield. Besides, the mentioned traits had a positive effect on root yield based on the results of path analysis both directly and indirectly.

Among the studied genotypes, cultivar F-20851 had the highest root yield in both irrigation conditions compared to other cultivars, so it can be concluded that the genotype has a high genetic potential for root yield production in different environmental conditions. Among Iranian cultivars, except for Paya cultivar, other cultivars had low ranks of root yield in both environmental conditions. It can be concluded that in addition to root yield, other enzymatic and biochemical properties of Iranian cultivars should be worked on to be competitive with foreign cultivars. In this study, proline content had a positive effect on root yield in both environmental conditions, so improving proline content could be a way to increase root yield in different environmental conditions.

Salt stress is one of the most important abiotic stresses, which decreases crop yields and limits the land use. Three hectares of agricultural land are being destroyed in each minute by salinity In Iran, salinity is one of the most important factors which limit the agriculture. Salt stress studies were very important in the most sugar beet planting regions of Iran based on sugar beet experts and farmers opinions producing sugar beet salt tolerant varieties, improving planting methods, irrigation and fertilizer use are the most Sugar Beet Seed Institute (SBSI) strategies for optimizing the production in saline lands.

In order to investigate the effect of salinity stress on quantitative and qualitative characteristics of sugar beet genotypes in normal and salinity stress conditions an experiment was conducted in a completely randomized block design with three replications in Miandoab Agricultural and Natural Resources Research Station at 2016-17 Crop seasons. In this research, 16 sugar beet genotypes were tested under two normal conditions and saline conditions with salinity of 12.1 dS/m. In this research, root yield, sugar content, white sugar content, sugar yield, the amount of sodium, nitrogen, and potassium of root, white sugar yield percent of sugar extraction was measured.Data was analyzed by using SAS 9.2 software.

The results showed that the effect of the environment on all studied traits wasn’t significant. Differences between genotypes were significant for all traits except for white sugar content, also the interaction of genotype in environment on all traits except the white sugar content was significant. Results showed that the highest root yield, white sugar yield and sugar yield in normal and salinity conditions were allocated to genotypes 14 and 15. Based on the results of correlation analysis in both environmental conditions, white sugar yield had positively and significantly correlated with root yield, white sugar content and sugar yield. Based on the results of stepwise regression analysis, root yield, percent of sugar extraction and sugar yield in normal conditions with justified 93 percent of white sugar yield variation and in salt stress condition with justified 84 percent of the total white sugar yield variation were identified as the most effective traits on white sugar yield.

In the present study, there was no significant difference between two years in term of studied traits. It can be concluded that climate conditions in the two years studied did not have a significant difference in terms of effect on the studied traits. In the present study, there wasn’t significant difference between normal and salinity stress conditions in terms of all traits and salinity Therefore, it can be said that sugar beet genotypes were resistant to salinity. In both environmental conditions, genotypes number 14 and 15 had the highest root yield, white sugar yield and sugar yield, Selection of these genotypes is recommended for future breeding programs. In both normal and salinity conditions root yield, percent of sugar extraction and sugar yield recommended as Criteria for selecting high-yielding genotypes.

Rhizoctonia root rot disease is considered as one of the important diseases in sugar beet. Using resistant cultivars decreses production costs, especially application of fungicides and increases the efficiency in controlling of root rot disease. Therefore, growing of resistant cultivars is considered the best approach for disease control. To achieve this goal and to determine yield potential of new sugar beet hybrids resistant to Rhizoctonia root rot disease, 92 hybrids as well as susceptible and resistant cultivars were evaluated in two experiments in research field of Ekbatan station of Hamedan, Iran in 2016. Considering the experimental results and with respect to the average effect of pollinators and single crosses, 20 hybrids were selected and evaluated in Karaj, Hamedan, Ghazvin, Torbate Jam and Shiraz regions in 2017. Evaluation of hybrids in term of resistance to rhizoctonia was simultaneously performed under micro-plot conditions in Hamedan. In both years (2015 and 2016), the experiment was conducted in randomized complete block design with six replications. The results of resistance evaluation under micro-plot conditions reavealed that five hybrids consisting; 9, 13, 16, 4 and 18 were more resistant than cv. Ekbatan for resistance to rhizoctonia root rot disease. Yield potential evaluation in different locations showed that new hybrids had desirable level of yield potential and most of them had no significant difference with cv. Ekbatan.Considering the results of resistance to rhizochtonia disease and yield potential evaluation, three hybrids no. 4 (SC(P.395*P.90)*P.165), no. 9 (SC(P.395*P.90)*P.121) and no. 16 (SC(P.395*P.23)*P.165) that were more resistance with higher yield potential in comparison with cv. Ekbatan were identified as promising hybrids for being evaluated in Value for Cultivation and Use (VCU) test.

Over 50% of the sugar beet fields in Iran are infested by rhizomania and beet cyst nematode diseases. Using resistant varieties is a simple and efficient method of managing these diseases. In 2015, Shokofa was released as the second domestic monogerm variety, resistant to both rhizomania and beet cyst nematode. White sugar yield of this variety under infested field condition was 7.44 tha-1 which was in the same group as foreign control Ludwina (8.28 tha-1) and domestic control Tous (7.32 tha-1). In an experiment conducted in greenhouse, the resistance of Shokofa variety to cyst nematode was evaluated and results showed that the average number of cyst on Shokofa root was 30, while two foreign controls including Pauletta and Sanetta infested with 23 and 26 cysts respectively, and the susceptible control Jolge was infested with 114 cysts. Based on two on-farm experiments conducted in Khoy and Fariman Sugar Factories in 2014, the sugar yield of Shokofa was 9.23 tha-1 that was almost equal to sugar yield of Toukan cultivar (9.47 tha-1), a foreign sugar beet control. However, under rhizomania infected fields in Neishabor and Qazvin Sugar Factories, the sugar yield of Shokofa was 7.17 tha-1 which was higher than all domestic and foreign controls.

In order to evaluate the effect of biofertilizers (nitroxin and phosphate barvar2), vermicompost and chemical fertilizers on the quantity and quality traits of sugar beet (Beta vulgaris L.), an experiment was conducted in randomized complete block design (RCBD) with 13 treatments and three replications at Agricultural and Natural Resources Research Station of Miandoab, Iran in 2015. The treatments were 100% chemical fertilizer (350, 100 and 50 kg ha-1 urea, superphosphate triple and potassium solphate) as control (T1), 10 t ha-1 vermicompost (T2), 20 t ha-1 vermicompost (T3), 10 t ha-1 vermicompost + 50% chemical fertilizer (T4), 20 t ha-1 vermicompost + 50% chemical fertilizer (T5), nitroxin + phosphate barvar 2 (T6), 10 t ha-1 vermicompost + nitroxin + phosphate barvar2 (T7), 20 t ha-1 vermicompost + nitroxin + phosphate barvar2 (T8), nitroxin + phosphate barvar2+ 50% chemical fertilizer (T9), 10 t ha-1 vermicompost + chemical fertilizer (196 and 85 kg ha-1 urea and superphosphate triple) (T10), 20 t ha-1 vermicompost + chemical fertilizer (40 and 70 kg ha-1 urea and superphosphate triple) (T11), nitroxin + phosphate barvar 2 + 10 t ha-1 vermicompost + 50% chemical fertilizer (T12) and nitroxin + phosphate barvar2 + 20 t ha-1 vermicompost + 50% chemical fertilizer (T13). The highest (47.8) and lowest (39.2) chlorophyll indices were obtained in T13 and T2 treatments, respectively. Also, the highest root yield (66366 kg ha-1) was achieved in T13 treatment that was not significantly different from T12 and T11. Due to a combination of organic and biological amendments with chemical fertilizers, sugar yield was increased significantly in T13 treatment due to increases in root yield and sugar content. The sugar yield and white sugar yield in T13 treatment increased 16.7% and 23.5%, respectively compared with T1. Generally, based on root yield, white sugar yield and extraction coefficient of sugar, integrated application of nitroxin + phosphate barvar2 + 20 t ha-1 vermicompost + 50% chemical fertilizer can be recommended for sugar beet production in the Miandoab area.

Water deficit and Rhizomania disease are two major obstacles in reducing yields in the sugar beet fields of Iran. Each year, various commercial varieties which have different kinds of resistance to disease, especially Rhizomania, are distributed to the sugar beet growers. Due to complexity of drought tolerance, development of drought tolerant varieties takes time and the progress is very slowly, so the introduction and use of high yielding varieties among these current varieties under less water conditions can be effective in reducing water consumption. In order to reach this goal, the reaction of 30 commercial varieties to low irrigation and Rhizomania reaction, was investigated in 2016 and 2017 in non-infected (Karaj) and infected (Mashhad and Miandoab) fields using a randomized complete block design. The irrigation method was furrow and irrigation periods, after two initial water for germination, was based on evaporation of 180 mm from the class A evaporation pan. Color, wilting and leaf senescence scores were evaluated in the middle of the growth season as well as the severity of disease to Rhizomania at harvest time. Root yield and sugar content were analyzed at harvest time. Water use efficiency (WUE) and superiority index (Pi) were calculated and evaluated. In these experiments, about 30% of water consumption decreased compared to control farms (irrigation based on evaporation of 80 mm from the class A evaporation pan.) .Aanalysis of variance showed that variety effect on sugar yield and water use efficiency (WUE) was significant (P˂ 0.01). It was confirmed that, in sugar beet, variety differences for water use efficiency are mainly due to differences in potential yield. The results showed that the ranking of the varieties differed in terms of the amount of sugar yield in infected conditions with non-infected conditions. In case of infection, the leaf color score and the severity index of the disease with sugar yield had a significant positive (R2= 0.44) and negative (R2= 0.39) correlation (P˂ 0.01), respectively. In non-infected conditions, the wilting and senescence score had a negative and significant correlation with sugar yield (r= -0.45* and -0.42*, respectively). However, in infected conditions with the disease, the correlation of sugar yield with the wilting score and leaf aging was negative but respectively, was not significant (r= -0.20, P> 0.05) and significant (r= -0.52, P

In order to study and compare the correlation between the quantitative and qualitative traits of sugar beet genotypes, using multivariate methods under Rhizoctonia disease a trial was carried out at Miandoab Agricultural and Natural Resources Station in 2014.The experimental design was randomized complete block design with four replications. The experimental materials were sixteen sugar beet genotypes. Analysis of variance showed significant differences among the genotypes for all traits, except root sodium content. Based on stepwise regression analysis, gross sugar yield, molasses sugar content and gross sugar content by justifying %89.99 of changes in white sugar yield were considered as the most effective traits in justification of white sugar yield. Factor analysis identified five factors by justifying 81.62% of total data variances. Finally, the three groups were set up in the cluster analysis at similarity distance of 10. The cluster 2 was subjected to groups a (the highest rate) for yellowing score, uniformity score, growth score, healthy plant number, root yield, gross sugar yield, white sugar content, white sugar yield and extract percentage, and was placed in group b (the lowest rate) for root potassium content and alkalinity. Eventually, based on path analysis and regression analysis, the gross sugar yield was determined as the most effective trait on the white sugar yield and the genotypes in cluster 2 were identified suitable for cultivation under the conditions of Rhizoctonia infestation.

In order to evaluation macro, micro, and chemical fertilizers on the quality and yield of sugar beet (Beta vulgaris L.), an experiment was conducted in randomized complete block design with 10 treatments and 3 replications at Agricultural and Natural Resources Research Station of Miandoab, Iran in 2016. The treatments were 100% chemical fertilizer as control, full micro-chelate nanofertilizer, NPK nanofertilizer, NPK nanofertilizer + full micro-chelate nanofertilizer, NPK nanofertilizer + 50% chemical fertilizers, full micro-chelate nanofertilizer + 50% chemical fertilizers, NPK nanofertilizer + full micro-chelate nanofertilizer + 50% chemical fertilizers, Fe nano+ Zn nano, Fe nano+ Zn nano+ NPK nanofertilizer and Fe nano+ Zn nano+ 50% chemical fertilizers. The results demonstrated that the highest and the lowest root yield and chlorophyll index were obtained in NPK nanofertilizer + full micro-chelate nanofertilizer + 50% chemical fertilizers and Fe nano+ Zn nano, respectively. Also, the highest sugar yield and white sugar yield were achieved in NPK nanofertilizer + full micro-chelate nanofertilizer + 50% chemical fertilizers. The highest content of α-amino-N, Na, K and molasses sugar was recorded in application of 100% chemical fertilizer. In addition to, minimum values of the mentioned indices were obtained in NPK nanofertilizer and full micro-chelate. Generally, application of NPK nanofertilizer+ full micro-chelate nanofertilizer+ 50% chemical fertilizers suggested as superior treatment and replacement of chemical fertilizers based on root yield, white sugar yield and extraction coefficient of sugar.

In order to evaluate quantitative and qualitative characteristics of different genotypes of sugar beet to rhizomania disease in Miandoab conditions 16 sugar beet genotype were ovulated in Agriculture research center in Miandoab during the 2014-2015 seasons. Experiment design was randomize bloke with six replications. Genotypes were exposed to natural infection area. In this experiment trait such growth rate, uniformity of roots, yellowing score, infection rates, severity rates, root yield, sugar content, sodium, potassium and amino nitrogen roots, white sugar content, sugar yield, alkaline, coffenetic of sugar extractions, white sugar yield and molasses content were measured. The results showed that between genotypes for all traits except for sugar percentage, alkaline and molasses was a significant difference. Result of means compare revealed genotype number of 33538 and 33540 showed high infection percent compare with other genotypes by average of 39.26 and 39.16 percent, furthermore genotype of F-20680 showed lowest of infection. In this study, there was no significant difference between the resistant genotypes of F-20680 with 33533 and 33551 genotypes in terms of infection rates, root yield, sugar yield and white sugar content. Therefore these two genotypes are recommended for other disease-breeding programs. Finally white sugar yield had positive and significant correlation with root uniform, root yield and white sugar and cougar yield and had negative and significant correlation with Sodium and alpha-amine.

In order to evaluate the genetic variation of drought tolerance-related traits in sugar beet half-sib families, two experiments including 37 half-sib families were conducted under normal and drought stress conditions using a randomized complete block design with three replications at Agricultural Research Station of Miandoab, Iran in 2014. Based on the results, significant difference was observed between normal and drought conditions for root yield, white sugar yield, sugar yield, cell membrane stability (P

Rhizomania is one of the most important diseases of sugar beet causing dramatic reduction in yield and quality. Because of the rapid spread of rhizomania in sugar beet fields, successful production of the crop is not possible without the use of highly tolerant cultivars. The aim of this study was to compare some of the agronomic characteristics of rhizomania-resistant hybrids with domestic and foreign commercial varieties. The study was carried out in randomized complete block design with four replications in four regions including Karaj, Mashhad, Miandoab and Zarghan in 2013-14. Seven promising hybrids together with three domestic (one susceptible and two tolerant) and two foreign cultivars as checks were evaluated. Different characteristics such as infection rate, growth score, root length and diameter, and also single root weight were measured. Infection rate was measured based on Luterbacher’s 1-9 scale. At harvest, roots were weighed and sugar content was determined. Infection rate results showed that roots produced in Karaj in 2014 and Miandoab in 2015 were free from the symptoms and therefore, these two regions were considered as non-contaminated environments. The highest rate of infection was observed in Zarghan in both years. Overall, (7112×SB36)×SB27 was selected as the superior hybrid in terms of root yield, sugar content, growth and root uniformity.

In order to assessment of sugar beet varieties by using multivariate statistical methods in agro ecological conditions mentioned in normal and drought conditions a field study was conducted in Agriculture research center in Miandoab during year of 2014.Result of combine analysis showed environment had significant effect Root yield, sugar content, the amount of sodium root, white sugar content, sugar yield, alkaline extraction of sugar and molasses. Difference between genotypes for all traits, except for the amount of potassium was significant. The interaction between environment and genotype had significant on all pages except white sugar yield. In represent study in normal and drought conditions white sugar yield had positive and significant correlation root yield, root potassium concentration, sugar yield and extraction of sugar. Based on cluster analysis genotypes were classified in 4 clusters under normal conditions that genotypes in cluster 2 had highest amount of root yield, sugar yield, the percentage of sugar white and white sugar yield than the average of the whole clusters and lower amount of sodium, potassium, amino nitrogen and molasses than average of the whole clusters. in drought stress genotypes were classified in 4 clusters that group of 3 had highest value of root yield, sugar percentage, amino nitrogen, the percentage of white sugar, sugar yield, extraction of sugar and white sugar yield than the average and had lower amount of sodium, sugar molasses and alkaline than average. The results of factor analysis showed in normal and drought conditions 2-factor were identified that explained 97.77 and 94.85 per cent of the total variance in the two conditions respectively.

To evaluate sugar-beet genotypes for their trait associations, two separate RCBD experiments with three replications were conducted both under non-saline (normal) and saline conditions at the Agricultural Research of Miandoab. Analysis of variance of the data collected showed that there were significant differences among genotypes for all traits studied under non-saline condition. But, differences of genotypes under saline condition were significant only for root yield, root potassium content, sugar extraction coefficient, impure and pure (white) sugar yields. Salinity stress, in this study, reduced root potassium content, root yield, sugar extraction coefficient, impure and pure (white) sugar yields. Mean comparisons of genotypes indicated that root yield of all genotypes, under non-saline condition, were higher than those of under saline one. As whole, genotypes number 1 and 2 produced higher root yields, impure and pure sugar yields respectively, under both saline and non-saline conditions. Based on the results obtained it was revealed that regression coefficients for the traits under study were significant. Step-wise regression and path coefficient analyses also indicated that traits like root yield, pure sugar and root nitrogen contents highly affected white sugar yield under non-saline conditions.

In order to study the effects of seed pre-treatment with potassium nitrate (KNO3), gibberellic acid (GA3) and hydro-priming on growth and yield of two sugarbeet cultivars, an experiment was conducted at Miyandoab Agricultural and Natural Resources Research Station in 2009 growing season. The experimental design was a factorial based on randomized complete blocks design with three replications. Two sugarbeet cultivars (Jolgeh and 7233-P29) and priming treatments at five levels (P1: non-priming or control, P2: priming with 3% KNO3 solution, P3: priming with 200 mg/L GA3, P4: priming with 3% KNO3+ 200 mg/L GA3 and P5; hydro-priming) were considered. Root yield, shoot weight, impure sugar yield, pure sugar yield, impure sugar percent, pure sugar percent, coefficient of sugar extraction, alkality and molasses sugar content were measured and evaluated. Results showed that the effect of cultivar was significantly different for root yield, shoot weight and pure sugar yield. Also, priming treatment significantly affected root yield, pure sugar yield and impure sugar yield. But, the cultivar × priming interaction wasnt significant for none of the measured traits. Comparison of means showed that root weight and pure sugar content of 7233-P29 cultivar was 14% and shoot weight was 34% more than Jolgeh cultivar. Among the priming treatments, maximum root yield (63.2 ton/ha), impure sugar content (10.7 ton/ha) and pure sugar content (8.1 ton/ha) was obtained from hydro-priming treatment. Therefore, it seems that hydro-priming, as an easiest method of seed pretreatment, can be helpful in improving the qualitative and quantitative yield of sugarbeet.

To evaluate the effect of artificial defoliation intensity at different growth stages on the root yield and quality of sugar beet (Beta vulgaris L.) a field experiment was carried out at Miyandoab Agricultural Research and Natural Resources Field Station in 2007 growing season. Experimental treatments were arranged as factorial (4×5) in RCBD with three replications. Defoliation were practice at four growth stages (S) of sugar beetincluding: plant establishment to 10% ground cover (S1), from 10 up to 70% ground cover (S2), from the S2 to root maturity (S3), and from the S3 to harvest time (S4). Five levels of defoliation intensities (I) were: blade removal up to 25% (I1), 50% (I2), 75% (I3), 100% (I4) and no defoliation as check (I5). At final harvest, sugar beet roots were harvested and root yield, sugar content, white sugar content, white sugar yield and extraction coefficient of sugar were determined. Results showed that the main effect of growth stage was significant on quality traits of sugar beet such as sugar content, white sugar content and sugar extraction coefficient, however, its effect on agronomic traits such as root yield was not significant. However, different levels of defoliation affected both quality and quantitative traits of sugar beet. At the 100% defoliation level, root yield reduced by 36% as compared to no defoliation (47.49 t.ha-1). In the meantime the least root yield (23.90 t.ha-1) was recorded at S2 with 100% defoliation (S2I4). The interactions between defoliation intensity × growth stages were significant (P<0.01) for sugar content and white sugar content. At the 25% defoliation (I1) at final growth stage(S4), sugar content decreased by 4.65 units whic was 22% of no defoliation (sugar content of 21.50%). In conclusion, any defoliation during the growing season may increase sugar losses in the sugar factory.

Understanding the relationship between root yield and other traits in sugar beet may be a crucial step towards successful breeding of this important crop. Path analysis provides a useful method in analyzing the genetic and phenotypic coefficients of correlations. This method is able to effectively unveil direct and indirect effects among traits of interest. In this research, root yield, yield components, some morphological traits and their relationships were investigated. The study included 0 different sugar beet genotypes that were planted in field under normal (Ec=. ) and salt stress (Ec= ds/m) conditions. Genotypes were also screened in greenhouse under similar conditions. Data analysis was done by calculating the coefficients of correlations between root yield and other evaluated traits. Then, using regression analysis a model including significant traits was developed. Finally, path analysis was used to dissect root yield with traits remained in the model into determine direct and indirect effects. Our findings indicated that under normal condition, traits including canopy cover and number of plants per m together accounted for 56 percen of the variation in root yield. However, under salt stress condition, four variables including canopy cover, number of plants per m, Na and K content together accounted for up to 87 percentage of the variation in root yield. Using path analysis it was found that under normal condition, canopy cover had a considerable positive effect (P = 0.554) on root yield while under salt stress, in addition to canopy cover (P = 0.599) the K+ content (P = 0.659) also indicated a considerable positive effect on root yield. We concluded that traits including canopy cover and K+ content may be used to accelerate the selection process in breeding programs wherever a huge number of germplasm has to be evaluated.

The aim of applying water stresses are two fold: a) to enhance Water Use Efficiency (WUE) and, b) to reach optimum-agronomic objectives (including, enhancing certain qualitative parameters of the crop, preventing excessive growth of aerial shoots of crops like sugar beet, etc.). This study was performed to evaluate the effect of irrigation interrupting time and its influence on the quality and quantity of sugar beet. The experimental design used Completely Randomized Blocks (CRB) methodology with 5 treatments; one to five weeks irrigation interruption before harvesting. Each treatment was planted on 5 lines with a 7 m length. The row spacing was 60 cm and the plants were 20 cm apart. The results of simple and combined analysis of variance in twoyears for different traits (root yield, impure sugar yield and white sugar yield, sugar content) showed that there is no significant impact by varying the parameters within the 5% statistical variance. Also, results of mean comparison for white sugar yield in the combined analysis proved that the greatest yield belonged to the 4th and 5th treatments with 9.11 and 9.12 ton/ha, respectively. Therefore, there is no significant difference regarding characteristics studied in statistical group, though even in some cases water stress can improve quality and increase sugar content percentage. So, irrigation interruption 4-5 weeks before harvesting in October can be suggested.

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.

In order to evaluate salinity tolerance in 20 sugar bee genotypes, an experiment was conducted in two fields with salinity (EC= 12 ds/m, pH= 7.6) and non-salinity stress, in the form of RCBD at Miandoab Agricultural Research Station. Different morphological and physiological traits such as root yield, sugar percentage, white sugar percentage, Molasses, N, Na, K, syrup purity and green cover percentage were recorded in salinity and non-salinity conditions. Germination percentage, seed vigor and establishment percentage were measured separately in a greenhouse experiment in karaj, using a factorial experiment based on CRD with two factors A (20 genotypes and B(two levels of salinity of 16 and distilled water). Arcsin transformation was used to analyze the data obtained from the greenhouse experiment. Results of the experiments showed a high variability among the genotypes and origins. Salinity stress caused 77% and 36% decrease in root yield and white sugar yield, respectively. The Na/K ratio was identified as a suitable criterion for selection of the tolerant salinity genotypes in field condition. The index of tolerance to stress was calculated for all of the genotypes and showed that the genotypes C3.3 (Tetraploid Multigerm) with index of 0.3 and 25.48 ton/ha yield had a good tolerance under field salinity conditions.In the greenhouse condition, genotypes C3.3 (Tetraploid Multigerm), 19669-p5 had a good tolerance under farm salinity conditions.