مجله چغندر قند
سال بیست و یکم شماره 2 (پاییز و زمستان 1384)

Development of resistant variety to powdery mildew (PM) is necessary. Therefore, during past years some of the sugar beet genotypes were screened to this disease in Kermanshah. One of the genotypes named 14442 showed resistance to PM disease. This genotype with two male sterile lines (MS261 and MS231) was used to determine the number of genes responsible for resistance to disease. Crosses between 14442, MS261 and MS231 were done and segregating generations were evaluated. Based on results, F2 plants in both crosses (14442*MS261 and 14442*MS231) could be divided in two phenotypic classes with ratio of 3:1. In back crosses two phenotypic classes with ratio of 1:1 were obtained. These results showed that PM disease was controlled with a single dominant gene.

Pathogenicity of 4 isolates of Erysiphe betae from 4 different geographical zones of Iran on 5 genotypes of beet, with different levels of resistance to powdery mildew, was investigated. Eight-week old plants were inoculated by conidia from 4 isolates separately. Indices for infection were estimation of leaf infection and number of produced conidia on the leaf surface 3 weeks after inoculation. Results indicated that there was no significant difference on the virulence level of 4 isolates but the genotypes showed significant difference in susceptibility to fungal isolates. The genotype 7233 indicated the highest susceptibility and two genotypes 10417 and 14442 showed highly resistance to powdery mildew. The genotype “Leaf Beet” which in the field experiments in Germany had proved resistance to the disease, in our greenhouse studies showed susceptible response. Conclusive results indicated that different isolates of E. betae belonging to different geographical zones were similar in pathogenicity and also greenhouse experiments can be an appropriate manner for screening sugar beet genotypes against E. betae.

The main purpose of this study was to measure the level of technical efficiency of sugar beet producers and determination of factors affecting it. A sample of 144 producers in the main sugar beet growing areas of Hamedan, Nahavand, Malayer and Asadabad were selected by two stage cluster sampling method. Data were collected through interviews during farming year of 2001-2002.Technical efficiency of sugar beet producers were estimated using Cobb-Douglas statistics frontier production functions. Also, the effects of various social and economical factors on the level of producers technical efficiency were studied. According to the results of this study, average technical efficiency for sugar beet growers of Hamedan and Malayer was estimated 0.73 and 0.70, respectively. There were much discrepancies between technical efficiency of the best sugar beet producers with that of the others. The production can be increased up to 27 and 30 percent in mentioned regions without any major change in technology and available resources, and only by decreasing the discrepancy between the best and the other producers. Age, experience and literacy of farmers, extension classes, visit of extension farms, and date of planting, planting method, seed kind and number of land units under sugar beet cultivation were the main social-economic factors affecting the technical efficiency of sugar beet producers.

In order to study the effects of planting date and sugar beet cultivars on infection to curly top virus, vector population, damping off, root rot, and sugar yield, an experiment was conducted in Mobarakeh region during 1999-2000 in a split plot design. The main factor was three planting dates and sub factor was six sugar beet cultivars: IC1 as a susceptible cultivar to beet curly top, T41R, 7233, H5505, PP8 and Attila with 4 replications. The results indicated that delaying in planting date until June, caused decrease of leafhopper population density. The populations of vectors (Circulifer tenellus and C. opacippennis) were the same in all sugar beet cultivars but their population in first planting were higher than the other planting dates and showed significant difference with them. The most infection to BCTV was observed in IC1 in first planting date, and showed significant difference with T41R and Attila at p<0.01 and p<0.05 respectively. In second and third planting dates infection to curly top decreased and there were not significant difference among cultivars. Infection of damping off and root rots decreased severely in 2nd and 3rd planting dates, Cultivars 7233 and Attila showed the highest infection to damping off and root rots in first planting date respectively. The least infection to damping off and root rots were observed in T41R. Delaying in planting dates until early July caused decrease of root and sugar yields, and significant differences were observed between third and other planting dates. T41R with 36.95 T/h had the highest root yield among cultivars and showed significant difference with Attila and 7233 at P<0.01 and P<0.05 respectively.

Sugar beet is an essentially self-sterile plant for which the vegetative propagation is used to obtain identical sister plants. Sugar beet micropropagation is initiated by meristematic cuttings. Sugar beet meristematic flower stalk explants were established in sterile cultures and used for shoot propagation. Two PGoB medium with different hormonal combinations: 1) BA/NAA/IBA at 1, 0.1 and 0.1 and 2) BA/NAA/GA3 at 0.5, 0.1 and 1 mg/l were compared for rate of shoot induction in three genotypes: IR428, IR445 and IR463 at 10 - 20 and 30 days after culture and at the time of transfer for root initiation. Experiment was conducted in a factorial design with time as the main plot, media and genotypes as sub plots, with eight replications each unit consisting of one shoot/culture vessel. Duncan's multiple range test was performed for mean comparison. ANOVA results showed that all factors (time, medium, genotype), had significant effects on micropropagation. More shoots were produced in the second medium as compared to the first. Mean no. of shoots varied among genotypes and increased with days after culture. In the first medium, genotypes were classified in three groups according to their mean no. of shoots but the two best (IR428 and IR463) appeared in one group in the second medium. Paclobutrazol treatment (0.2%) applied on microplants foliage and utilization of a water culture device, designed to support microplants to gain photoautotrophic growth.

In this study, recently produced fungicide Opus was compared with current fungicides Dinocap, Sulfur and Calyxin for controlling powdery mildew disease of sugar beet in completely randomized block field experiments conducted in Kermanshah and West Azarbaijan provinces. Fungicides were applied according to the recommended field dosages. There were five treatments (four fungicides plus a water-spray control) each with four replicates. Disease incidence was evaluated 15 days after the last application based on infection index on sugar beet leaves collected from different treatments. Infection index varied from 1 (no infection) to 6 (81-100% infection). Analysis of the results indicated that in Miandoab experiment for both years there were significant differences among different treatments in disease incidence and the fungicide Opus was the most effective in reducing infection. In the first year of Mahidasht experiment there were no significant differences among different treatments due to very low occurrence of the disease in the field. In contrast, in the second year significant differences were observed in different treatments. Despite higher root yield and sugar content in fungicide treatments, compared to the control, these differences were not significant.

This experiment carried out to evaluate replacing effects of Oyster shell (OS) with filter cake (FC) of sugar beet industry on performance and quantity and quality of egg in laying hens. In this trial the filter cake in two physical forms of powder and pellet in five levels of 0, 25, 50, 75, and 100% replaced for oyster shell. Each treatment had 3 replications. The experiment lasted 3 periods of 28 days. Feed intake and egg weight were measured every week and egg quality was recorded every month. Results indicated that replacing OS with FC up to 50% level in the form of powder, had no significant effect on feed intake, egg weight, egg mass production, laying rate and feed conversion ratio (P>0.05). Replacing powder FC more than 50% caused significant reduction in egg mass production, laying rate and feed efficiency (P<0.05). However, using pellet FC at all levels had no significant effects on these traits. Replacing OS with FC had no significant effect on egg quantity and quality characteristics. It is concluded that the best and suitable level of replacing FC in powder or pellet form is 50 percent in laying hens nutrition.

At the present time 33 sugar beet and 7 sugar cane industrial units are active in the country. In 2004, the national sugar production was about 1192 thousand tons, that 55 percent of it was produced from the sugar beet and the rest from the sugar cane. In this investigation the status of sugar beet root and sugar production during last 4 years is discussed. The theoretical capacity of 33 sugar industrial units is 67650 tons sugar beet root per day. With attention to 100 working days, the total consumption capacity of sugar beet root is about 6.75 million tons per year. Unfortunately, because of many reasons sugar beet production and consumption capacity have not reached to the optimum levels. The average sugar beet root production in last 10 years is 49830000 tons. Based on the published statistics by the association of sugar industrial units the ratio of purchased sugar beet root to the official capacity of the sugar industrial units is about 81 percent and the ratio of consumed sugar beet root to the official capacity of the sugar industrial units is about 67 percent. These facts show that although some problems exist in industry and agricultural sections however no clear solutions have been proposed. During agricultural year 2004 about 4913000 tons sugar beet root with 17.32 percent sugar content have been produced in 156000 hectares by 95000 farmers. Where, the total produced sugar was 659000 tons. In table 1 the average production of root and sugar during 4 years was demonstrated. Results of some investigations show that the yield of 30 tons per hectare is the border line to profit or loss. It is clear that cultivation of varieties with root production capacity less than 30 ton per hectare should not be recommended. Maybe over estimating of the land under sugar beet cultivation leads to wrong conclusion. So, real estimation of the land under sugar beet cultivation needs scientific method. In spite of existing suitable ecological and environmental condition for sugar beet cultivation in most regions because of using inaccurate method of soil management, ignorance of agronomical requirement aspects and lack of extinction to transfer the results of research to the farmers, the potential production has not been achieved yet. Evaluation of the data of the Iranian sugar industrial units shows considerable difference between their performances. The reasons could be insufficient payments at appropriate time to buy sugar beet root or other requirement of industrial sectors and old technology and production line. So, under this condition most of sugar industrial units could not achieve their theoretical capacity. In addition, about 4 percent of sugar beet root deteriorate in sugar industrial unit. Transporting sugar beet root from one area to the other area is another problem that sugar industries are put up with.