Journal of Sugar Beet
Year:2010 | Volume:26 | Issue:1|Papers Count:9

Understanding the relationship between root yield and other traits in sugar beet may be a crucial step towards successful breeding of this important crop. Path analysis provides a useful method in analyzing the genetic and phenotypic coefficients of correlations. This method is able to effectively unveil direct and indirect effects among traits of interest. In this research, root yield, yield components, some morphological traits and their relationships were investigated. The study included 20 different sugar beet genotypes that were planted in field under normal (Ec=1.1) and salt stress (Ec=12 ds/m) conditions. Genotypes were also screened in greenhouse under similar conditions. Data analysis was done by calculating the coefficients of correlations between root yield and other evaluated traits. Then, using regression analysis a model including significant traits was developed. Finally, path analysis was used to dissect root yield with traits remained in the model into determine direct and indirect effects. Our findings indicated that under normal condition, traits including canopy cover and number of plants per m2 together accounted for 56 percen of the variation in root yield. However, under salt stress condition, four variables including canopy cover, number of plants per m2, Na and K content together accounted for up to 87 percentage of the variation in root yield. Using path analysis it was found that under normal condition, canopy cover had a considerable positive effect (P=0.5534) on root yield while under salt stress, in addition to canopy cover (P=0.5919) the K content (P=0.6591) also indicated a considerable positive effect on root yield. We concluded that traits including canopy cover and K+ content may be used to accelerate the selection process in breeding programs wherever a huge number of germplasm has to be evaluated.

In order to transfer rhizomania resistance genes to improved sugar beet lines, crosses were made between 11 commercial resistant varieties and two improved inbred O-type lines of sugar beet (231 and 261) at Agricultural Research Center of Khorasan Razavi and Jam sugar factory in 2007. O-types carried self fertile (Sf) genes and contained male sterile (MS) genotypes. Commercial varieties were used as pollinators and inbred lines as female parents. Males and females were examined for the amount of hybrid seeds production, yellowish color of leaves and infection index of rhizomania on the root. However, seeds were harvested from 299MS plants within O-types. Males and females were compared based on the amount of viable seeds produced on each plant. The results showed that females did not represent significant differences although the line 261 produced 54.2 percentages of hybrids with enough viable seeds when compared to the line 231 with 45.8 percentages. Pollinators were significantly different at 5 percentages probability level in respect of producing consequent hybrids with enough seeds. Scales of yellow color of leaves and resistance index of roots were statistically similar to the growth period of plants. The results displayed that crosses originated from various pollinators reacted differently (at 5% probability level) to yellow color change of leaves and root infection index to rhizomania during the growth period. The lowest percentage of green leaf belonged to the population No. 8 and the highest to No. 7 that figured about 0 and 80.8 percentages, respectively. The highest disease resistance index appeared for the No. 7 and the lowest for pollinators like numbers 2, 8, 10 and 11; but progenies of test crosses resulted from populations No. 3,4 and 5 were also ranked in the resistant group. Therefore, progenies obtained from later mentioned populations have higher potential than others in transferring resistance genes into sugar beet lines. The results displayed that crosses originated from various pollinators reacted differently (at 5% probability level) to yellow color change of leaves and root infection index, but females (231 and 261) did not represent significant differences.

Root and crown rot of sugar beet caused by Rhizoctonia solani AG2-2 is a destructive disease in the main sugar beet growing areas. Use of resistant cultivars is the most effective and environmentally safe way to control the disease. In order to find resistant genotypes, 70 sugar beet lines together with resistant and susceptible checks were evaluated against a highly virulent isolate of R.solani AG2-2 in the designed micro plots (1*1*2 meter) at Ekbatan Agricultural Research Station, Hamadan. Before seed sowing, manure and fertilizers were added to the micro plots, then disinfected by methyl bromide. The experimental design was a randomized complete block with 42 treatments and two replications. The fungal isolate was grown on corn kernels. Ten-week old plants were inoculated with 6-8 corn infected kernels in crown area. The micro plots were watered immediately after inoculation. Roots of sugar beet were harvested 80 days after inoculation and disease severity of individual roots were assessed according to a 1-9 scale where 1 represents the healthy plants and 9 represents the dead plants. Mean diseaseratings of plants in each plot was considered as disease index (DI). Results of two year mean comparisons and cluster analysis displayed that three lines with respect to disease resistance and 11 lines with respect to harvest index were superior to the resistant check (SB19) and other lines were at the same group as the resistant check. However, one of the lines had a higher disease index than the resistant check.

Spodoptera littoralis (Boisduval) is one of the major pests of sugar beet in southern parts of Iran and host plant resistance is an important component of its integrated management. Because of some problems in experimentation under natural field conditions, this study was conducted to evaluate the resistance of 4 sugar beet cultivars ("6/7232mu","Rasul 1","Shiran2","4/7112 Hybrid") using leaf discs and detached leaves under laboratory conditions. Host preference of neonate larvae was evaluated using leaf discs (15 mm diam) placed on a filter paper within a petri dish (10 cm diam) and replicated five times (20 larvae per replicate). Leaf damage was examined by detached leaves, embedded in 3 percentage agar-agar in a plastic jar (500 ml capacity) infested with 5 larvae, using a randomized complete block design with 4 replicates. The experiments terminated when the of the more than 90 percentages first leaf was damaged. Results showed that there was no significant difference among cultivars for host preference of neonate larvae while they differed for leaf damage significantly (P<0.05). The cultivars "6/7232 mn" and "4.7112 hybrid" with mean of 5.25 and "Shirin2" with mean of 8.5 showed the lowest and highest leaf damage, respectively. The cultivars did not show significant differences in larval survival and larval weight. Based on the results, sugar beet detached leaf assay can be used as a rapid, inexpensive technique to evaluate sugar beet germplasm.

Beet Necrotic Yellow Vein Virus (BNYVV) is the causal agent of sugar beet rhizomania, disease . In the present study which was conducted in 2005 in Shiraz, Iran, serological methods (including ELISA) were used for detection of disease and screening of disease tolerant germplasm in sugar beet breeding programs. For doing this, Iranian isolate of BNYVV was purified and a specific antiserum was prepared against it. The virus was propagated on Chenopodium quinoa leaves by mechanical inoculation of sap extracted from the infected sugar beet leaves. Purification of BNYVV from C. quinoa comprised of extraction of infected sap in phosphate buffer, primary clarification, high speed centrifugation through a cushion of 20% sucrose and sucrose density gradient centrifugation. The light-scattering band of virus particles was formed in centrifuge tubes with more densitymainly in three sections. For preparation of antiserum, the purified virus was injected subcutaneously into a New Zeland rabbit. DAS-ELISA system was developed after isolation of γ-globulin from absorbed antiserum and preparation of enzyme-antibody conjugate. This antiserum could be used in the related research at education and research organizations. The antiserum produced was of high quality and did not react with the healthy plant sap.

This study was conducted to determine the yield response factor (Ky) of sugar beet to deficit irrigation at different growth stages. A field experiment was conducted in Sharekord Agricultural Research Station over two growing crop seasons (1996 -1997) using a randomized complete block design with three replications. Plots were assigned to five levels of deficit irrigation treatments: E0 (Full Irrigation), E1 (85%), E2 (70%), E3 (55%) and E4 (30%) of actual evapotranspiration of sugar beet plant at three growth stages T1: leaf growth stage, T2: tuber growth stage and T3: sugar accumulation growth stage. Reference crop evapotranspiration and potential evapotranspiration of sugar beet was determined by drainage lysimeter using neutron meter. After maturity, root yield, yield components and yield response factor were measured. Results showed that yield was highest (49.500 t/ha) in E0 (Full irrigation) and lowest (24.6 t/ha) in E4T2. Actual evapotranspiration of sugar beet was 884mm. The values of yield response factor (ky) were 0.34- 1.38 at the first stage, 0.34- 1.33 at the second stage and 0.34- 1.39 at the third stage and the lowest evapotranspiration (625 mm) was obtained in E4T2.

An experiment was conducted to evaluate the effect of lime application on the mass and sugar losses reduction from 2004 to 2005 in Karaj. Four lime concentrations of 0, 3, 4 and 5 percent (factor A) and storage durations of 30 and 60 days (factor B) were arranged as factorial experiment in RCBD with four replications. The commercial variety of Shirin was drilled in early May and storage roots were harvested late November each year. Weight and technical quality of beet samples such as sugar content, reducing sugar, sodium, potassium, amino-nitrogen, modulus of elasticity and root rot percentage were determined before and after each storage period. Air temperature inside the pile recorded daily using a max- min thermometer. Mean air temperature of silo in the first and second 30 days storage in year 2004 was 0.75 and 0.50 ºC greater than that in 2005, respectively. The results of combined ANOVA showed that effect of year was significant for mass loss, amino-nitrogen, dry matter content, reducing sugar (P<0.01), modulus of elasticity and root rot (P<0.05). Sugar losses, sugar content and amino-nitrogen in dry weight, molasses sugar, dry matter content and modulus of elasticity were affected significantly (P<0.01) by storage duration. Lime concentration had significant effect on modulus of elasticity (P<0.05) and sugar content in dry weight of sugar beet (P<0.08). There was no interaction between lime concentration and storage duration for sugar beet traits. Spraying lime concentration of 3 percent on the beet reduced root dehydration by 2 percentages and consequently modulus of elasticity increased by 0.39 MN/m2 in comparison with the check treatment. Although, sugar losses were not affected by lime application but sugar content (in dry weight) was 1.5 percentage more than and mass loss due to spraying lime concentration of 3 percentage was significantly less than both 4 and 5 percent concentrations. In conclusion, pre-washing sugar beet and then spraying lime with the concentration of 3 percentage before storage may reduce root dehydration and improve modulus of elasticity during the storage in conditions similar to the Karaj region.

Most regions of Iran are confronted with inadequate supply and excessive demand of water in agriculture sector mainly resulting from a high difference between water providing cost and its price. Coping with such a challenge needs to determine the water price based on the economic principles and its value in agricultural production. The aim of this study was to determine the economic value of the water using production function analysis throughout the sugar beet growers of Marvdasht district. The data was obtained from 50 farmers in 2006 that were selected by a two stage cluster sampling method. The results of production function revealed that inputs water, labor and fertilizer had positive effect on the production. The coefficients showed that 10 percent increase in labor use will increase the production by 1.58 percent. The corresponding figures for water and fertilizer were 3 and 3.4 percent respectively. The final value obtained from each cubic meter of water was obtained 211.6 Rials. While the price paid by the producers was only 26.8 Rials per cubic meter. The results of the demand function also showed that water price doesn’t affect the water demand significantly while increased product price will raise the water demand.