Journal of Sugar Beet
Year:2007 | Volume:23 | Issue:1|Papers Count:12

Water use efficiency (WUE, the ratio of total dry matter to water use) became a breeding target only when it was found that carbon stable isotopes were inversely related to WUE. The current study conducted under well-watered and drought conditions in the field over two years at Broom’s Barn Research Station, UK, was undertaken to investigate the extent of genotypic differences for water use, yield, WUE, carbon isotope discrimination (Delta), and the associated traits. The results indicated that the varieties differed in WUE and sensitivity to water deficit stress at 5% probability level. However, this variation was not related to gas exchange characteristics. Variation in Delta as measured on leaf tissues was negatively correlated with WUE indicating that genetic variation in WUE could be indirectly exploited by measuring carbon isotope composition in plant organs, especially in leaf tissues. As variation in Delta and hence WUE may arise from variation in stomatal conductance, photosynthetic capacity or both, the traits theoretically associated with stomatal conductance (leaf ash content and canopy temperature) and photosynthetic capacity (chlorophyll content and specific leaf weight) were measured among which only specific leaf weight (leaf dry weight per unit area) was significantly associated with Delta (r= 0.77, P<0.01). This indicates that specific leaf weight could be used when there are not enough resources to use Delta directly and as an initial screening tool to cull the inferior genotypes in the early phases of breeding programmes aimed at improving WUE.

This study was carried out in order to identify the effects of soil water depletion (SWD) on monogerm sugar beet (cv. Shirin) seed growth trend at different growth stages. An experiment was conducted in randomized complete block design (RCBD) with three replications in Ardebil Agricultural Research Station. During 2002 and 2003 cropping seasons, nine treatments including control (irrigation after 50% SWD), irrigation after 70 and 90% SWD in bolting, early flowering, peak of flowering and seed growth stages were compared. Treatments of irrigation after 70 and 90% SWD led to the saving of water use by 1.8 and 18.3%, respectively compared with the control (3167 m3/ha). According to the results, SWD at different growth stages had no significant effect on crude, marketable and standard viable seed yield compared to the control treatment. However, the highest water productivity was obtained after eliminating one of the irrigation intervals, particularly at peak of flowering stage  which based on crude (1166 kg/ha), marketable (917 kg/ha) and standard viable (250 kg/ha) seed yield equates 0.450, 0.354 and 0.096 kg sugar beet seed/m3 of water use, respectively. Stress during seed growth period led to an increase in standard seed portion, which was due to a decrease in oversize seed portion. The depletion of 90% SWD at early and peak of flowering stages increased chaffy seed percentage from 7.55% (control) to 9.35 and 9.34%, respectively. The highest germination rate was obtained at early flowering stage (81.88%) in control and 90% SWD at early flowering stage, but stress at other growth stages of sugar beet seed-bearing plants decreased seed germination rate. On the other hand, stress at peak of flowering stage increased seed growth rate by 0.0534 mg/day, and irrigation after 70% SWD at early flowering stage had the highest effective grain filling period (38.73 days). The highest seed weight was obtained about 35 days after 50% flowering (1.971 mg/seed) in the treatment of the irrigation after 70% SWD, being 0.195 mg/seed heavier than the weight of seeds from control treatment.

In order to determine the effects of water deficit at different growth stages of sugar beet and optimal usage of water on quality and quantity characters of sugar beet, a factorial experiment based on randomized complete block design was conducted with 13 treatments and four replications in 2000 and 2001 in Agricultural Research Center of Hamadan. For the first factor, irrigation withheld in three growth stages consisting of S1,  foliar growth stage (8-10 leaf stage or about six weeks after planting), S2, root growth stage(after 8-10 leaf stage) and S3, stage of sugar accumulation (near the end of growth stage). The second factor included the number of irrigations withheld at different growth stages of sugar beet from one (I1) to four (I4) times. A control treatment was also included with no water deficit. Combined analysis of variance showed that there were significant differences among different growth stages sugar content, juice extraction of sugar and white sugar content. The growth stages were also significantly different with respect to Na+, K+, and the amount of molassed sugar. Significant differences were also observed among irrigation treatments for all characters except alkalinity. The interaction of growth stages with irrigation treatments was not significant. Maximum sugar content and white sugar content at final harvesting averaged over the two years was obtained from S1I1 (withholding irrigation for one time at foliar growing stage) and the minimum amounts obtained from S3I4 (withholding irrigation for four times at the stage of sugar accumulation). Withholding irrigation near the end of growth stage decreased sugar content, white sugar content and juice extraction of sugar. In general, water deficit at the end of sugar beet growth stage increased the impurities of root including K+, Na+, and consequently decreased juice extraction of sugar and increased the percentage of molassed sugar.

The main objective of this research was the measurement of soil characteristics, land evaluation and determination of potential yield of sugar beet in Yekanat plain of Marand. For doing this, firstly, yield potential of sugar beet was estimated by FAO method and secondly land evaluation of different soil units for sugar beet cultivation was determined by parametric method. Results showed that Marand region is not a suitable area for rainfed sugar beet cultivation because the growing period of this region is shorter than that of sugar beet. However, the region does restrict the production of irrigated sugar beet. Potential root yield of sugar beet was estimated about 77 ton/ha by applying FAO method. Evaluation of land units using parametric method showed that the whole studied area can be classified into 5.8% moderately suitable (S2), 26.75% suitable but low profitable (S3) and 52.9% unsuitable (N) classes. Strong correlation between parametrically calculated land index and observed yield (r2=0.86) indicated the high accuracy of this method for land evaluation. Soil salinity is the main limiting factor for sugar beet cultivation in this area. Topography, slope of lands, soil coarse fragments and weak field management can be mentioned as other factors in yield decrease

Beet necrotic yellow vein Benivirus (BNYVV) as one of the most important virues of sugar beet is the causal agent of rhizomania. BNYVV, as a type member of genus Benyvirus has four types A, B, P and J, that are restricted to specific geographic areas. Types A and B are similar in pathogenicity, but P and J types that have RNA5 are more aggressive. These types cannot be distinguished serologically. For detection of BNYVV types in Chenaran region, 28 samples of sugar beet roots showing the suspicious symptoms of rhizomania were collected from vicinity of Chenaran sugar factory during growing season in 2006. At first, BNYVV was detected in the samples by DAS-ELISA and RT-PCR. Virus type was determined in the infected plants by specific primers and RT-PCR from 28 examined samples, BNYVV was detected in 23 and 25 samples by ELISA and RT-PCR, respectively. RT-PCR using specific primers of virus type produced only a specific band sized 324 bp, therefore, only type A of BNYVV was detected in the infected samples.

Cover type of on–farm storages has an important role in reducing the freezing damage and respiration of beet roots in the pile. This experiment was conducted in 2006 in Karaj region in order to evaluate the effects of cover types of storage on the mass and sugar losses of both topped and untopped beets. The experimental design was a split plot factorial in RCBD with three replications. The main plots consisted of: a1- a layer of wheat straw with 10-15 cm depth, a2- a layer of sugar beet top with 10-15 cm depth, a3 - propylene cover with 0.55 mm diameter and a4- without cover as a check. The sub plots consisted of a combination of two storage durations: b1- 30 days and b2- 60 days with two types of beet topping: c1- topped and c2- untopped. The size of pile was 2 meters width, 1.5 meters height and 3 meters length in the N-S direction. Air temperature inside and outside the pile was recorded daily using a max- min thermometer. Weight and technical quality of beet samples were determined before and after storage. The results showed that mean air temperature under all covers were greater than uncovered treatments. Mass losses of sugar beet under covers were significantly less than those of uncovered treatment. Molassed sugar of beet under both straw and propylene covers were significantly less than other cover treatments. Mean sugar loss in the first 30 and 60 days were 489 and 279 g/t/d that may be related to greater respiration rate of sugar beet in 30- day storage. Sugar loss of untopped beet was 88 g/t/d less than that of topped beet. In conclusion, under conditions of this experiment, covering sugar beet with both propylene and straw covers under on-form storage had less molassed sugar and maybe considered as suitable pile covers. Sugar losses of untopped beets lacking any petiole were less than that of topped beets. Thus, untopped beets maybe recommended, for storing sugar beet in on-farm storage

For considering and evaluating the economic impacts of sugar beet research on the shift of sugar supply, we need to estimate the parameter of supply shift. Having developed an appropriate methodology and using the results of breeding research collected from the main stations of sugar beet research across Iran for the period of 1982-2003, the supply shift parameter for sugar was estimated.  This parameter indicates the percentage horizontal shift of the sugar supply curve.  The percentage of sugar yield shift averaged over the period of 1983-2003 was compared to the base year (1982) for each station and the difference was considered as the performance of the station. The highest performance was seen at Mashhad station (17.21%) and the lowest at Shiraz station (-4.84%). In addition, Karaj, Hamedan and Dezful stations demonstrated positive performance whereas Miandoab and Kermanshah stations had a negative performance. The 22-year average of the parameter was 7.18% through the country. It means that Iranian sugar beet R&D policy increased the nation's welfare by more than 7%.

Sugar beet is one of the main crops in Iran that provides primary materials for sugar industries and so, its economic aspects are very important. One of these aspects is employment; it has begged to draw policy maker attentions. Nevertheless, there hasnot been any survey study on this matter in Iran yet. In this study, the current value of labor use in sugar beet cultivation (direct employment) in Isfahan, Khorasan, Fars and Kermanshah provinces was identified. Data were collected through stratified random sampling and complete farm accounting questionnaire for different technologies levels. Then, the labors needed to transfer of sugar beet to sugar industries and produce the products (sugar, Molasses and so on) from sugar beet (forward employment) were calculated. Data for these steps were gathered by completion of the questionnaires for each step. Results showed that the average use of labor was 140.48 man-day per hectare. This value was 153.31, 144.85 and 133.81 man-day in traditional, mechanized and semi-mechanized, respectively. Maximum uses of labors were in thining and weeding (41.43%), harvesting (39.11%) and irrigation (34.28%) activities. Also, the average use of labor in all of studied provinces was 43.68 man-day per ton of gross sugar yield from which 31.03 man-day (71.04%) was used in production step, 3.322 man-day (8.08%) in transfer step and 9.119 man-day (20.87%) in conversion step. Furthermore, the average use of labor was 7.15 man-day per ton of gross sugar yield in all steps and provinces. Therefore, 253207 people have been employed in sugar beet industry of Iran.

Rhizomania (root madness) is caused by Beet Necrotic Yellow Vein Virus (BNYVV). This disease was first reported from Italy in 1959 and from Fars, Iran in 1996. During the recent years, it has been increasingly developing across the country so that most beet production areas such as Khorasan, Fars, West Azarbaijan, Isfahan and Kermanshah are now more or less affected by the disease. Typically, the taproot remains small and weak and becomes turgid. Also, a higher number of hairy roots appear at the end of or along the root. Yield reduction due to the disease can be significant. As the cultural practices have proved to be ineffective economically and environmentally, breeding the disease resistant varieties has been paid attention to control the disease and sustain the beet production. The first step in improving the disease resistant varieties is to find the resistant resources among the cultivated and wild germplasms of sugar beet. Breeding Rhizomania resistant varieties has become a breeding objective of high priority at Sugar Beet Seed Institute (SBSI), Karaj, Iran since 1998. Having studied the domestic and foreign germplasms of sugar beet during 1998-2000 at the infected fields of Zarghan Agricultural Research Station (Fars), SBSI found the resistant resources. A pollinator population was found to be of a higher resistance compared with the other resources evaluated under natural and artificial (glasshouse) infections. Therefore, by selecting resistant single plants from this population, the level of resistance increased to a greater extent and a new parent was derived which had, in addition to a high resistance, proper agronomic and technological characters. For this reason, it was selected as the pollinator parent. In 2000, 26 hybrids were derived from two breeding programs among which the above-mentioned tolerant pollinator as well as some other male parents was contained. The resulted hybrids were evaluated in multi-environment trials (MET) under diseased and disease-free conditions. In addition to disease resistance of the hybrids, some other traits such as root yield, sugar content and technological characters were also studied in the MET trials. The genetic combination of the new hybrid was found to be one of the most successful combinations. The hybrid was also studied in on-farm (Demo) trials of the sugar factories during 2004-2006.