Journal of Sugar Beet
Year:2004 | Volume:19 | Issue:2|Papers Count:11

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 pathogens 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.

To determine the role of Fusarium species associated with sugar beet root and crown rot, diseased samples were collected from different fields of sugar beet in Iran including Khorasan, Khuzestan West Azarbayejan, Qazvin, Tehran, Kermanshah ,Kerman,Lorestan ,Hamedan,Charmahal Va Bachtiary provinces during growing seasons 1999-2002. In total, 94 isolates of Fusarium were obtained. Based on morphological characters , six species including: F. solani, F. oxysporum, F. equseti, F .nygamai, F. proliferatum and F. culmorum were identified. The pathogenicity of isolates was determined through inoculation of sugar beet slices of main root using agar disc inoculum and seedling inoculation in greenhouse conditions using sterilized soil and wheat seed Inocula. Disease symptoms including root and crown rot , seedling damping-off and wilting in the greenhouse conditions, and rotting of slices of main root were evaluated. Results revealed that except one isolate of F. solani the rest were pathogenic on both seedling and root slice and produced one of the two types of Fusarial disease symptoms (wilting or root rot). Some isolates of F.solani were more aggressive than the others.

Phenotypic coefficient correlation is a relation criteria for traits. This coefficient can be used to differentiate insignificant traits of varieties in selection programs. This survey was carried out with 10 breeding populations and susceptible controls in normal and stress conditions. The drought field was irrigated when plants reached wilting point. Traits such as leaf length and width, petiole length, root yield and length, white sugar yield, N, K, Na/K, root dry weight and shoot wet and dry weight were studied in stress and non stress conditions. The data were analyzed and correlation coefficients were determined using, Pearson's method. The results showed that in normal condition correlation between RY and WSY, K, Na/K and RDW was significant. The relation between RY and WSY, RDW and SDW was significant in drought conditions. The correlation between RY and WSY, RDW and SDW was significant in saline conditions. The results also showed that the morphological traits measured in this survey were very important, particularly in stress conditions. In drought stress conditions, selection for small and few number of leaves and in saline conditions, the low amount of storage of sodium in root is very important for breeding programs.

A field experiment was carried out during 2001 in the experimental fields of Sugar Beet Seed Institute in Karaj. The objective of this study was to determine the response of some quantitative and qualitative traits of three sugar beet lines subjected to continuous water stress and normal conditions. Three sugar beet lines 7219-P.69, BP-Karaj and 7112 as tolerant, semi tolerant and sensitive to water stress , respectively, were subjected to continuous water stress gradient using a line-source irrigation system. Three irrigation treatments (full irrigation, slight and severe stress) were applied after complete plant establishment. That these treatments received 1274, 1133 and 740 mm of water and produced root yield of 58.6, 45.8 and 34.7 t/ha, respectively. In severe water stress, the concentration of k+ and α-amino-N increased, but the concentration of Na+ decreased. Thus, in the stress conditions white sugar yield (WSY) was reduced. The comparison between sugar beet lines showed that the line 7112 had greater WSY under both stress and non-stress conditions. However, the WSY loss of the sugar beet lines due to water stress was 36, 32 and 24% for BP-Karaj, 7112 and 7219-P.69, respectively. In conclusion, the line 7219-P.69 demonstrated the less WSY loss when subjected to continuous water stress conditions. This phenomenon is an indication of different responses of sugar beet lines to type and severity of induced drought stress and possibly it is due to complexity of plant tolerance to drought stress.

This research was carried at The University of Reading in 1999. The aim was to estimate the effects of 18 hd-1 (long-day, LD) and 12 hd-1 (short-day, SD) light exposure duration of plants before bolting or flowering on time to bolt and flower in two bolting susceptible (BSG, IC1) and bolting resistant (BRG, SAXON) genotypes of sugar beet. So, two experiments were conducted. The experiments were carried in a glasshouse containing two compartments. The photoperiod in compartments one and two was adjusted to 18 hd-1 and 12 hd-1, respectively. In the experiment one, the aim was to determine duration from root replanting to bolting and flowering. So, plants were exchanged from LD to SD and vice versa at 0, 8, 21, 33, 40, and 47 days after root replanting. In the experiment two, the aim was to determine the duration from bolting to flowering. So, at first step we let all the plants bolt in the LD and then they were reciprocally exchanged from LD to SD and vice versa at 0, 8, 16, 24, 40, and 30 days after bolting. Results showed that BSG responded to LD from root replanting whereas BRG had a longer photoperiod-insensitive pre-inductive phase. The resistant genotype plants did not bolt even after 180 days. When BSG plants were exposed to SD after bolting all of them eventually flowered. This results indicated that by the time of bolting, photoperiod requirement for flowering was also fulfilled, whereas BRG needed further inductive photoperiod after bolting to flower. Therefore, bolting and flowering are two independent phenomena and they require different LD cycles. BSG is a quantitative LD plant in which bolting and flowering occur sooner in LD than in SD. However, very resistant genotypes (e.g. Saxon) showed a more or less obligate requirement for LD and did not bolt in 12 h photoperiod within 180 days after root planting. So, it is suggested that sensitivity to day-length seems to be a good selection tool to reduce the tendency for bolting in plant populations.

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 questionnaires 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.

There are a number of methods (protocols) used in different laboratories for extraction of genomic DNA from plant and fungus sources, dependening on the quantity and quality of the required DNA. However, the basic principals of DNA extraction procedures are the same in most of them (2, 4-6). Regarding researches based on molecular marker conducted at the biotechnology laboratory of Sugar Beet Seed Institute, There seems to be a simple, low cost and efficient method needed for genomic DNA extraction from plant or fungus materials. The extracted DNAs are prerequisite to accomplish PCR-based molecular analysis. Therefore, some DNA extraction protocols were compared (1-6) and a simple and repeatable method useful for plant and fungus materials was obtained. Finally, the protocol was applied and the extracted DNAs from two sources of fungus and plant were considered as template DNAs in specific PCR and RAPD analysis after quantification and qualification. DNA banding patterns showed that the DNA extraction protocol was efficient for both sources (Fig. 1). This DNA extraction method takes less than three hours and compared to the most commonly used methods in molecular biology laboratories it has been proved to have lower cost.