مجله چغندر قند
سال بیست و یکم شماره 1 (بهار و تابستان 1384)

For determination of water stress effects in different growth stages of sugar beet and optimum water usage on quantity and quality of sugar beet, this study was performed using randomized complete blocks design in factorial experiment with 12 treatments and 4 replications from 1999 to 2001 in Agricultural Research Center of Hamadan. The first factor was non-irrigation in 3 stages of growth (S1-S3) and the second was non- irrigation with 4 levels (I1-I4). Experiment was performed with 12 treatments and a control without drought stress. The combined analysis results showed that there was significant difference among root yield, sugar yield and white sugar yield in interaction of different growth stages and year levels. There was significant difference (P≤ %1) in interaction of treatments and year on relative water content and soil moisture percent. There was significant difference in interaction of different growth stages and year on water use efficiency for root yield, sugar yield and white sugar yield. Maximum water use efficiency obtained from S1I2 (not-irrigated for two times in the leaf growth stage) and the minimum obtained from S2I4 (not-irrigated for four times in the root growth stage).Non-irrigation for more than one time in sugar beet different grail stages cause damage on qualitative and quantitative characters. In general, drought stress in relation of the time and stress intensity decreased yield and quality of sugar beet. Reduction of root and sugar yield root growth and sugar accumulation stages was more severe.

Interspecific or intergenus hybridization in sugarbeet (B. vulgaris L.) is usually failed due to non fertilization, embryo death or absence of connection between embryo and endosperm. Consequently invitro embryo rescue technique is of value to save hybrid embryos before annihilation. Sugar beet inter-specific crosses with wild species is impossible in classical breeding because of no chromosomal homology. In this research, the inter- specific crossing of beet was performed manually using tetraploid plant (B. vulgaris L.) as female and two wild species: B. webbiana Mog and B. procumbens Chr.Sm. as male parents. Artifical fertilization of female plant flowers was performed manually. Embryo growth observation was carried out using 1% tetrazolium chloride treatment. Fertilized flowers were collected 20 days after pollination and hybrid embryos were cultured in three experiments with different media composition invitro conditions and kept in darkness at 25°c.The third experiment with N6 medium containing GA3, AB, NAA and P.V.P. at 1, 0.2, 0.5 and 300 mg/l respectively and 3% sucrose, 1% active charcoal and 6% agar showed best results. Germinated embryos were transferred to N6 medium with 0.5 mg/ l BA and 1mg/l GA3 and placed in 16/8 photoperiod condition. The results showed that the percentage of germinated embryos and hybrid plantlets obtained from two mentioned crosses were 40% and 10% respectively.

The main objective of this study was to determine the economical level of inputs applied in production of sugar beet by Eglid region farmers. Therefore data set was obtained From 55 farmers through interview and completing questionnaire. The farmers were selected based on a two-stage random sampling method. Marginal productivity of inputs was studied using Cobb – Douglas and Transendental production functions. Transcendental production function was also used to determine the relative cost share of inputs. Based on findings, labor, machinery and seed are used more than their optimum levels, while chemical fertilizer was used less than its optimal amount. Selected farms are expected to get maximum profit by using reduced amount of labor, machinery and seed and increased amount of chemical fertilizer. The results showed that about 67.2 percent of farmers were in non-economic region of production. 85.5 percent of farmers have also been in the second stage of production in fertilizer consumption. Seed and machinery have been used higher than their optimal amounts by 100 and 58.2 percent of the farmers respectively. 56.4 percent of the farmers were in second stage (economic) of production in using pesticides. High coefficient of determination of 0.88, indicated that 88 percent of changes of dependent variable can be explained by independent variables. The results also indicated that the highest share of cost was related to labor and machinery and the profit will rise if their use is reduced.

In order to study the effects of Farm Yard Manure (FYM), Sulfate of Potassium (SOP) and boric acid on quality and quantity of sugar beet, an experiment was conducted in split plot factorial with four replications during 3 years (1999-2001) in Bardsir- Kerman. The FYM was the main plot in 3 levels: 0, 10 and 20 ton.ha-1. SOP was applied at levels, 0, 75 and 150 kg.ha-1 and boric acid at levels 0, 10 and 20 kg.ha-1 which treated in subplot. The results showed that the effect of FYM and SOP on root yield were significant, but boric acid did not have significant effect on increase of moelasses sugar and white sugar content. FYM and SOP application changed sugar beet yield significantly, so that using of 20 t ha-1 FYM and 150 kg.ha-1 potassium sulfate increased white sugar yield 10% and 6% in comparison to the check. Boric acid had no significant effect on white sugar yield. but it increased the white sugar yeild about 1.8% in comparison to the check.

Due to high antagonistic activity of Trichoderma harizanum, 5 isolates T.h.K, T.h.BI, T.h.Mo, Var33 and Torbat VI were selected and their efficacy was studied for controlling sugar beet damping-off caused by Rhizoctonia solani, under in vitro and in vivo conditions. Antagonistic ability of T. harzianum isolates was investigated as dual culture on PDA in concomitant and sequential cultures, 48 and 96 hours after R. solani culturing. It was found that all T. harzianum isolates colonized R. solani colony, stopped its mycelial growth and sporulated on it. In all 3 experiments, the isolate T.h.K, colonized R.solani colony in a shorter time compared to other isolates. Microscopic observations showed that these isolates coiled around, penetrated and degenerated hypha of R.solani, stopped its growth and finally lysed it. Volatile metabolites of T. harzianum isolates had significant inhibitory effect on mycelial growth of the pathogen, among which T.h.BI isolate with inhibition percent of 89.63% had the best effect. In investigation of inhibitory effect of 5 concentrations (% 10-% 15-% 20-% 25-% 30) of culture filtrates of T. harzianum isolates in reduction of R. solani mycelial growth, it was found that none of the isolates at the above concentrations had any effect on R. solani mycelial growth. In greenhouse experiments, it was cleared found that seed coating or soil drenching by antagonistic agents had significant effect in reduction of seedling mortality, 30 days after sowing in comparison with infected control and there were significant differences among the isolates. Isolates T.h.K and Var33 in soil drenching method, had the best effect in controlling of the disease.

In order to reduce herbicide utilization, a 3-year field experiment was carried out with integration of mechanical and chemical weed control methods; in mechanical method, three types of blades (curred- bed knife, square- turn knife and sweep) were used. Chemical control was done with Chloridazon (WP 80%) and Desmedipham (EC 15.7%) in two spraying sheme: Once band sparying with 2 L h-1 & twice band sparying with 1 L h-1 of herbicides with 10 days interval. Combinations of chemical and mechanical control treatments were compared with conventional control methods including hand hoeing and overall field spraying with 6 L h-1 of herbicides. The results indicated that the best method of weeds control was the combination of cultivation with square-turn knif and once band spraying with 2 L h-1 of herbicides. Generally, our results showed that band spraying and cultivation, can reduce herbicides usage about 66% that is important from economical and environmental point of views.

Sensivity of seed germination stage to saline soil is the main obstacle to proper field establishment of sugar beet crop. In previous studies different tissues of sugar beet showed high tolerance to salt stress by of increasing sodium chloride levels in in vitro condition. An experiment was by to study the response of sugar beet zygotic embryos to salt stress in in vitro conditions. Sterile perfect seeds and naked embryos from salt sensitive (9597-67) and salt tolerant (7233) lines were cultured in PGoB medium and four levels of salinity: 0, 100, 150 and 250 mM NaCl, with three replications and 10 explants/Petri dish. Dishes were kept at 25º ± 2º C and 2000 Lx for a period of four weeks. A factorial design was used in statistical analysis. Mean values were compared using DMRT and F test. Naked embryos of both lines sprouted in both stress levels whereas their perfect seeds did not. There were significant differences between the plant material, salt levels and their interaction. Furthermore seed advancement experiment with an eight hours Thiram, (0.2%) treatment and gradual decrease of seed moisture content at 25º C was performed. This treatment included 25 seeds /dish of three sugar beet lines and the same salt levels in water agar medium with 4 replications. Treated seeds of all three lines germinated in stress conditions. Results showed that lines, stress levels and their interaction were significantly different. The line 7233 was the most tolerant genotype followed by 9597-67 and 261. The benefit of 'seed Advancement ' treatment for tolerance to salt stress conditions was demonstrated.

Many fungi cause sugar beet root rot during various stages of the plant growth. Among them Rhizoctonia spp. induce crown rot, dry rot and violet root rot on sugar beet (Whitney and Duffos,1986). Root rot caused by Phytophthora drechsleri has been observed in fields with excessive moisture (Habibi,1975). Pythium aphanidermatum has been recognized as one of the causal agents of sugar beet, damping-off, root rot and seed deterioration (Ahmadinejad and Okhovat, 1976). Rhizopus arrhizus has been also reported as one of the fungi involved in crown rot of sugar beet (Habibi,1977). In order to determine pathogenic fungi involved in sugar beet root rot and their distribution in Kermanshah province, this investigation was carried out during 1998-1999. Forty-one fields in different parts of the province were surveyed. At every field some information about previous crop in rotation, method of irrigation, source of irrigation water and disease severity was recorded. From each field, 2-5 root samples showing root rot symptoms were collected and transferred to laboratory. A soil sample was also collected and analyzed in the laboratory. Ninty eight isolates belong to Fusarium spp., Rhizoctonia solani, Binucleate Rhizoctonia, Phytophthora drechsleri, Pythium aphanidermatum, Rhizopus arrhizus, Rhizopus stolonifer, Macrophomina phaseolina, Phoma betae, Mucor spp. and Geotrichum sp. were isolated. In this study, although the majority of the isolates belonged to Fusarium spp., they could not induce root rot symptoms in pathogenicity tests. The most severe symptoms of root rot were induced by R. solani, P. drechsleri, P. aphanidermatum and R. arrhizus. Among soil specifications, only soil saturation percent had a weak relationship with disease severity and other factors showed no distinct relation with disease symptoms. Figure 1 shows distribution of the fungi involved in sugar beet root rot in Kermanshah province.