جهانشاه بساطی

Powdery mildew of sugar beet is a common disease in many sugar beet growing areas causing root yield and sugar content reduction. The aim of this study was to evaluate the effects of different irrigation methods on powdery mildew severity in sugar beet. Eight susceptible and resistant commercial cultivars were evaluated under sprinkler and furrow irrigation systems in a randomized complete block design with four replications for two years at Mahidasht station, Kermanshah, Iran. The combined analysis results showed that the infection index in furrow and sprinkler irrigation systems was 49.1 and 5.9%, respectively. Sprinkler irrigation had significant effect on the control of powdery mildew. The highest and the lowest rates of infection were observed in SBSI004 (36.6%) and Brigita (10.62%) cultivars, respectively. Furrow irrigation yielded 0.7 t/ha higher root yield than sprinkle irrigation, although it was not statistically significant. The highest root yield (65.13 t/ha) was noted in cultivar Brigita. The effect of irrigation on sugar content was significant with 15.04% in furrow irrigation and 13.59% in sprinkler system, respectively Therefore furrow irrigation resulted in 1.45% increase in sugar content and also lower accumulation of sodium and amino nitrogen in roots.

In order to study fruit quality changes in apple cultivar Gala, related to ripening stage and storage time, an experiment was conducted in a split plot arrangement in Randomized Complete Block Design with four replicationsin the area of Damavand– Jaban for three years. Five levels of sampling times in storage were assigned to main plots, and three levels of harvesting times were randomized in sub plots. Flowering time was recorded for six selected trees. Fruit was harvested during ripening process, every week, based on the starch index (1-5). The samples were tested for total soluble solids content (TSS), titratable acidity (TA), weight decrease, fruit firmness, flavor and acceptability. Harvested fruits were stored in storage under 0 ± 1°C temperature and 85 ± 5% relative humidity, for five months. The optimal fruit quality was achieved when the fruits harvested in 110 days after full-blooming with 2.0-2.5 starch index.

Water and soil salinity in some regions of Isfahan, East Azerbaijan, and West Azerbaijan provinces and also other parts of the Iran are the main hindrance for crop planting. Seeds of the tolerant crops to salinity such as cotton and sugar beet may have optimal germination and give acceptable performance if they become far from salt accumulation areas. To evaluate the effects of different planting methods on the quantity and quality of sugar beet in areas with salinity restriction, an experiment was carried out in a split split plot design in three replications in 2004-05, in Research Station of Rudasht, Isfahan. Irrigation with two salinity levels including 8 ds/m and 12 ds/m were allocated to the main plot, two planting dates to the subplots, and three planting methods including two rows under water mark, rows in flat plot, and on ridge to the subplots. Results showed that irrigation with 12 ds/m salinity level compared with 8 ds/m caused 17 and 18 % reduction in root yield and sugar content, respectively. Root yield was highly influenced by water salinity. Delay in planting, caused 31, 46 and 30% reduction in root yield, sugar content and sugar yield, respectively. Reduction in both white sugar yield and sugar yield was owing to root yield reduction. No significant difference was found among three planting methods. White sugar yield and sugar yield were higher in two- row planting method compared with two other methods. Delay in planting caused a significant decrease in sugar yield which is not recommended. Two- row planting method is recommended owing to more simplicity in irrigation, mechanized planting and also a decrease in production cost compared with two other methods.

Powdery mildew disease caused quality and quantity losses of sugar beet production. Therefore, five spraying treatments and three sugar beet variety were conducted in split plot design with four reapplications during consecutive two years in Kermanshah and Mashhad regions. In order to control of disease, tridimorph fungicide was used. Spraying treatments were in main plot and variety in the sub plot. Combine analysis showed that severity index less in sprayed treatments. With increasing number of spraying, severity index (SI) was decreased. Four times spraying had less SI (22.42 %). Treatment without spraying had the highest level of SI (43.39 %). Treatment with four times spraying had the highest root yield by about 69.3 t ha-1. One time spraying caused increase 2.8 t ha-1 root yield. Four times spraying than control treatment (without spraying) had 5.8 t ha-1. Sugar content was not affected by spraying with fungicide.

For development of pollinator parent resistant to powdery mildew disease of sugar beet، relatively resistant 14442 population was used. Based on resistance index، 50 resisitant plants were selected to produce half sib family (H. S. F). After random pollination between these 50 plants، seed of H. S. F was harvesed. From these 50 plants، only 39 plants had produced enough seed. Next year these H. S. F were planted in one raw plots with six replications and evaluated for disease resistance. After evaluation، 3 H. S. Fs (H. S. F13، H. S. F24 and H. S. F35) with high level of resistance were selected. From those 3 families، 150 roots were selected to produce new half sib families (N. H. S. F). Between these 150 families only 88 roots produced enough seed. In the next cycle، 88 N. H. S. F were evaluated for disease resistance and 3 N. H. S. F (H. S. F5، H. S. F17 and H. S. F22) with high level of resistance were selected. From each N. H. S. F، 35 roots were selected to produces. In the cage، from 105 roots only 13 plants produced enough seed. In the next year 13، S1 again evaluated again for disease resistance. Low level of infection (12. 9 %) was observed in the S1 lines. Therefore، selection in the 14442 population for powdery mildew resistance was very effective، and plants selected in this method showed 72. 6 % selection progress. Because of the good resisitance of the S1 lines، they could be used to develop powdery mildew resistance varieties.

Sugar is important from the point of both energy source and food security for Iranian householders. The considerable part of internal consumption is imported. Sugar beet is one of the most important sources of sugar, as a raw material in the world and also in Iran. For food security and self sufficiency programs, considering comparative advantages of sugar beet cultivation is one of the most important aspects of economic planning and economic incentives of producers is important for the goals of government planning. In this study, sugar beet comparative advantage was determined by applying Domestic Resource Cost (DRC) and Social Benefit Cost ratio (SCB) criteria to data of 2004-05 farming year with two levels of exchange rates in Kermanshah provinces. The protective policies of the government were analyzed by Matrix Analysis of Policy (MAP). Based on findings of this study, Kermanshah has high comparative advantage on this crop under competitive and real price condition, but under existing condition producer receive negatives economic incentives and pay implicit tax to government.

In order to further understand the emergence and germination of sugar beet monogerm cultivars under moisture stress, the current study was carried out at three stages. At the first stage, the quality of germination of three monogerm cultivars (Rizofort, Rasoul and Zarghan) were studied under five moisture stress levels (0, -2, -4, -6 and -8 bars) in germinator at 15°C by between-paper method. At this stage, after the onset of the germination, the number of germinated seeds was daily counted and at the end, germination percentage and rate was determined. The second stage was similar to the first one with the difference that at this stage, the percentage of normal and abnormal seedlings was determined 14 days after sowing and then, radicle length, coleoptile length and their ratio as well as radicle and coleoptile dry weight and their ratio were measured for each treatment. At the third stage, the studied cultivars were evaluated in clay soil in growth chamber under moisture stress of 17.5, 20, 22.5 and 25% (control) of soil volumetric moisture. At this stage, when emergence started, the number of emerged seeds was daily counted and then, emergence rate, days to 50% emergence and final emergence percentage were determined for each cultivar and treatment. The statistical design of all stages was a two-factor factorial (the levels of the factors were different at each stage depending on the number of treatments) based on a Randomized Complete Block Design with four replications. The studies were carried out in the laboratories of Agricultural and Natural Resources Research Center of Kermanshah, Iran. Results of the first study showed that moisture stress significantly impacted germination percentage and days to 50% germination, so that as moisture stress was intensified, germination percentage decreased. Also, results revealed that germination percentage of cv. Rizofort was higher than that of Rasoul and Zarghan. Results of the second study indicated that moisture stress significantly affected normal seedlings and ungerminated seeds at 1% probability level. According to the results of the third study too, moisture stress significantly influenced emergence percentage, emergence rate and days to 50% emergence. Results showed that the emergence of sugar beet seeds dramatically decreased at soil volumetric moisture level of lower than 17.5% (-6 bars soil tension) and the emergence percentage of sugar beet seeds did not significantly change with the increase in clay soil volumetric moisture level from 20 to 25% (soil tension of -3 to -0.3 bars).

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.

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.

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.

In order to study effective factors in sugar beet production using two stage cluster sampling, totally one hundred producers were selected from kermanshah and Islamabad cities in kermanshah province. Data were collected through interviews and filling out questionnairs for crop season 1999-2000. Evaluation of technical efficiency of sugar beet producers and its effective factors was carried out using cob-Douglas productions functions and Maximum likelihood Method. Results showed that average rate of technical efficiency of farmers was 82 percent in kermanshah and 77 percent in Islamabad. The effects of the number of fields, previous year culture, fertilizer usage based on soil analysis, time of the last irrigation, culture method and reading extension materials were evident on sugar beet producer technical efficiency.

To study the effect of powdery mildew on sugar beet yield and percentage of sugar losses sugar percent losses, ten genotypes were compared in a factorial experiment based on randomized complete block design with 3 replications and two factors. The first factor was spraying treatment with two levels and the second were genotypes. Inoculation was carried out using the pathogen's conidial suspension. Disease severity index was calculated based on the Wang's scale 6 weeks after inoculation. Data showed that fungicidal application increased root yield(16.5 %). However the positive response of the genotypes to chemical control of powdery mildew was variable. Increase in root yield varied from 0.5 tons/ha in Bulk 7233 to 19.7 tons/ha in the genotype 7233 p.107 Response of genotypes was also different in sugar percent and in the sprayed treatment sugar percent increased. Maximum sugar increase (2.2 %) was obtained in the genotype 7233 p.107.

Sugar is very important role in humanbeing feed. for sugar Beet production in tropical area detemine sowing and harvesting date is very important. For this reason three sowing date (1 sep, 20 sep and 10 oct) and three harvesting date (15 Apr, 15 may and 15 jun) in complete Blouck design as factorial with three replication in two year in Sarpol area condoucted. Results showed that the first sowing date has highest bolting and third sowing date has lowest bolting. Thirs harvest date has highest level of bolting. Root yield in the first sowing date more than the other. Interaction between two factors showed that 1 Sep sowing date * 15 May harvesting date for root yield was very better than the other interaction factors. The best date of sowing in this area was until 20 Sep and for date harvest was 15 May. For development of sugar beet caltivated in this area need to more investigation.

One of the biggest barriers for agricultural production in Iran is water deficit. However, certain optimum approaches for water application can solve this problem. Deficit irrigation technique is an approach that could have a better and economic use of water in agriculture. In this regard, a research with three factors including two irrigation intervals of 8 and 12 days, two nitrogen fertilizer levels based on soil analysis result and 2/3 use of it, and four levels of irrigation, 100, 80, 60, & 50 percent of crop water requirement, was performed on sugar beet during 1998-1999 in Mahidasht agricultural research station, Kermanshah province. The experimental design was a Factorial Split Plot with Randomized Complete Block arrangement and three replications, in which irrigation intervals represented the main plot and nitrogen fertilizer along with irrigation levels represented the sub plots. Furrow irrigation method was used and the amount of applied water was measured with a flowmeter. The combined analysis of data showed that the amount of water had a very significant effect on root yield, white and gross sugar yield. Root yields of 52.5 and 48.2 t/ha were obtained from 100 and 80 percent of crop water requirement, respectively. However, from the economic point of view, the 80 percent water requirement treatment had the highest net benefit. The irrigation intervals of 8 and 12 days had no significant effects on sugar beet yield components. Therefore, the 12 days irrigation interval was recommended. Finally, the nitrogen fertilizer treatment did not show any significant effect. There was no significant difference between the nitrogen fertilizer treatments.