مجله چغندر قند
سال بیست و ششم شماره 2 (پاییز و زمستان 1389)

In order to study the response of new sugar beet hybrids and cultivars to curly top disease in the field conditions, an experiment was carried out in a randomized complete block design with four replications and sixteen treatments in 2007 in Fasa. Each plot included a hybrid or cultivar planted in three rows with eight meter length and 50cm between- row spacing. After weeding and first thinning, percentages of the infected plants were calculated based on the morphological characteristics of the young plants. Disease index was also measured for each treatment. At the end of growth period, the quantity (root yield and white sugar yield) and quality (sugar content) of in all treatments were measured and compared. The results showed that there was a significant difference in the percentage of infected plants and disease index among the hybrids and cultivars (α=1%). Two hybrids 28957 and 28914, had the lowest infection percentage and disease index of 3.970, 1.175 and 3.940, 1.280 percentages respectively. Cultivars H2301, BRANCO and CHINOOK had the lowest infection percentage and severity to curly top. There was also a significant difference among the hybrids and cultivars regarding root yield, white sugar yield and sugar content (α=1%). The highest root yields(78.57, 77.98 and 71.90 tha-1) and white sugar yield(11.75, 12.27 and 11.55 tha-1) were recorded for H2301, BRANCO and CHINOOK cultivars, respectively. The hybrid 28957 with 9.30 tha-1 white sugar yield was superior to the other hybrids. The maximum sugar content obtained from the cultivar CHINOOK and hybrid 28910, 18.39% and 18.23%, respectively. Therefore the hybrid 28957 are recommended as two curly top tolerant hybrids for producing resistant cultivars.

Sugar beet cyst nematode (Heterodera schachtii Schmidt) is transferred to sugar factories along with the sugar beet root and its surrounding soil, so called depot soil. Because of high infestation and the possible transfer and distribution of this soil, disinfestations of the depot soil should be taken into considerations. In order to assess the possibility for disinfestations of the depot soils in Esfahan sugar factory, an experiment with four treatments including; solarization (using transparent polyethylene sheet of 30µ thickness), undecomposed farm manure, the combination of solarization and farm manure and control (no operations) were compared in three replications at four various depths (0-5, 5-30, 30-45 and 45-60 cm) for two continuous years. Before and after the experiment, the populations of eggs and second stage juveniles were measured. The results showed that the combination integrations of soil solarization and farm manure had the highest effect and significantly reduced the nematode population as compared with the other treatments, especially at the depth of 0-5 cm. The population reductions in the respective depths in the combination of solarization and farm manure were 99.85, 99.8, 98.5 and 96.8 percent and those in control were 8.4, 36.4, 5.97 and 49.06 respectively. The farm manure and solarization treatments were not significantly different, but they were different from the control.

The most problematic weed in summer crops in Alashthar town is ground cherry (Physalis divaricata). In this research, the emergence pattern of this weed in sugar beet and wheat crop was investigated during 006- 007. Seed dormancy was also studied from October to May in two depths 0 and 0 cm, based on a factorial experiment. The results indicated that the emergence of this weed starts late April and continues up to July and 70 percent of germination occurred in May and 45 percent in the first half of May. Emergence Growing of weed in wheat crop occurred early July (30 percent) and continued up to early September (45 percent) From October to May, the germination of seeds buried at two depths (0 and 0 cm) was more than 88 percent. This indicated the lack of seed dormancy for the majority of ground cherry population. Therefore, irrigation and plowing after wheat harvest is very important in controlling this weed.

Water stress is one of the main factors affecting the quantity and quality properties of sugar beet. The objective of this experiment was to study the effect of irrigation management on quality and quantity of sugar beet. The present research was conducted in Motahary Station of Sugar Beet Seed Institute, Karaj in two years, 005 and 006. The experiment was based on split plot design, in which eight irrigation regimes (non-stress, three levels of withholding irrigation at early growth stage, two levels of continuous drought stress and two levels of withholding irrigation in late season) were allocated to the main plots. Three sugar beet genotypes, 9, BPMashhad and BPKaraj, were assigned to in the sub plots. Sugar content (SC) was influenced by beet water content. In order to study the effect of irrigation managements on this trait, It is recommended to determine SC based on dry weight of roots. Sever early drought stress reduced sodium quantity as compared to the other irrigation levels. Nitrogen content was increased significantly by both levels of continuous drought as compared to the other irrigation levels. Generally, continuous drought (mild and serve) decreased alkalinity and increased the marc percentage. The maximum marc percent was observed in two levels of continuous drought. The lowest root and sugar yield were observed in two levels of continuous drought stress. White sugar yield in severe irrigation withhold in the early season was significantly higher than that of the mild stress during the season. Although, other low irrigation managements had less root yield than non-stress condition but the differences were not significant (P> 0.05). White sugar yield was decreased in two levels of continuous drought stress as compared to non-stress conditions. This important property was not affected significantly by other levels of irrigation treatment. The genotype 9 had more white sugar content and extraction coefficient of sugar, and less Na and alkalinity than the other genotypes. The interaction between genotypes and irrigation was in significant for all traits.

In most of the sugar beet cultivated areas including Kermanshah, Iran, late season irrigation is cut- off earlier than usual which causes drought stress in the crop. Since root yield still increses in Sept. and Oct. these areas, withholding irrigation in this period reduce root yield and quality of sugar beet. For this reason, an experimente was conducted during 004- 005 based on split plot design with four replications in Kermanshah. Withholding times (, 0, 0 Sept. and 0 Oct) were assigned to the main plot and three on- form silage period (0, 0 and 30 days) to the subplots.Withholding irrigation on 0th Sept had the lowest root yield(4.4 tha-) and that of 0th Oct. had the highest root yield (50.96 tha-) indicating that the later the irrigation cut- off, the higher the root yield is. Silage for 30 days decreased root yield about 8.5 percentage. Sugar content was not greatly affected by irrigation cut- off and silage treatments but sugar yield is an important character in sugar beet production. Because sugar yield was not significantly affected by irrigation treatments, in some water limited aren and irrigation cut- off in 0th or 0th Sept is recommended.

The research was carried out to study the effect of Controlled Deficit Irrigation (CDI) on quality and quantity of sugar beet in Bardsir region of Kerman and Karaj during 005- 006. In this experiment, irrigation treatments were studied in a randomized complete block design with three replicates. Crop water requirement was calculated in two- day periods. The treatments were implemented in different intervals (, 3, 4, and 5 days) at three growth stages (vegetative development, root swelling and ripening). The irrigation system used was tape. After harvest, quantity and quality of sugar beet were determined and combined analysis was carried out for two years and two locations. To illustrate the relationship between the volume of water used as an independent variable and the measured traits as dependent variables, correlation coefficients were calculated and regression analysis was conducted. Irrigation treatments had significant effects (P< 0.05) on all traits except potassium, sodium and α-amines. Considering the root and sugar yield, WUE, sugar content, and Industrial Quality Index (IQI), the treatments T9 (medium water stress in development and ripening stages) and T0 (severe and medium water stress in ripening stage) were recommended. Total consumed water in the two above treatments Bardsir were 6840, 6944 and in Karaj were 7758, 7849 (m3ha-) respectively which was about 3 percentage less than the water the applied. in T (control). These treatments were also the best in the combined analysis of each region. The results showed that water stress in root swelling stage was more effective on decrease of root yield than the other growth stages. The lowest WUE was observed for the treatments which had no water restriction or were exposed to the moderate deficit irrigation in different stages of plant growth (T, T, T3)

Plant analysis is successfully used in monitoring nutritional status, recommending fertilizer rates and types, and maximizing fertilizer efficiency in sugar beet. Diagnosis and recommendation integrated system (DRIS) is a comprehensive approach which does not have limitations of the critical value approach (CVA) and sufficiency range approach (SRA). Over- dose application of fertilizer increases root yield but decreases crop quality. In this investigation, the amount of nutrients in leaf samples and yields from 383 fields throughout Khuzestan province were determined for three years. Then, database containing 5500 data including yields and concentration of nutrients was made. According to the DRIS method, the whole sampled fields were divided into two low and high yielding populations based on root yield of 53 tha- and white sugar yield 6.3 tha. Then, all forms of expression were determined in each sub-population and the variance was calculated. In order to select the best reference norms, the largest variance ratio (SB/SA) was taken into account. Finally, 55 reference norms were selected. DRIS indices were calculated using Excel software. Mean concentration of NO3-N, N, P, K, S was 0.89, 3.98, 0.7, 3.6, 0.5 percentage and for Mn, Zn, Fe, Cu and B was 09, 34, 36, 6.5 and 40 mgkg-. In order to check the precision, accuracy and usefulness of the norms and indices, the results of two fertilizer experiment were evaluated. The results showed that these reference norms as well as the DRIS indices seems to be useful in determining nutritional status of sugar beet.

Soil compaction reduces growth of secondary roots, soil aeration and water and mineral uptake by plant, and decreases chlorophyll content as well as root yield and sugar content. Hence, the effect of soil compaction on sugar beet yield and sugar content farms determined by penetrometer using 40 plots of 00 m in 40 sugar beet field of Hamedan, Asadabad, Malayer and Bahar at the depth of 0-80 cm. At harvest, some traits such as root yield (RY), sugar content (SC), white sugar content (WSC), sugar yield (SY) and white sugar yield (WSY) were determined in an area of 4.4 m per plot. Linear multiple regression of yield and sugar content as depended variable, with the compaction of soil at the depth of 0- 80 cm, as in depended variables, showed that soil compaction at the depth of 4-60 cm (4. MPa) reduced root yield, sugar yield and white sugar yield dramatically, but these traits were not affected by soil compaction at the depth of -40 cm and were even increased by soil compaction at the depth of 0-0 cm. Therefore, soil compaction more than four MPa at the depth of 0-60cm reduces sugar beet yield and quality.