مجله چغندر قند
سال بیست و هشتم شماره 2 (پاییز و زمستان 1391)

For continues production if field crops in arid and semi arid regions of the world, such as Iran, beside of using of drought resistant varieties, water management must also be considered. In this context, the use of tape drip irrigation system could reduce the amount of irrigation water consumption. This study, was conducted to determine the best sowing pattern of sugar beet under type drip irrigation system, at Motahari station of Sugar beet seed institute(SBSI), Karaj, Iran during 2009 and 2010. Experiment was carried out in a randomized complete block design with three replications and seven treatments including sowing patterns with row distances of 45, 50, 60, 40-50 and 60- 40 cm and placing tapes every other rows and two sowing patterns with row distances of 50 and 60 cm and placing tapes on all seeding rows. The amounts of water applied in all of the treatments were almost same. Results showed that row distances of 60 cm with placing tapes every other row led to the lowest and highest number of roots and amount of root potassium, respectively, as compared with the other treatments. The highest sugar and white sugar yields and also water use efficiency for white sugar yield were achieved in sowing patterns with row distances of 60-40 cm and placing tapes every other rows and row distances of 50 cm and placing tapes on all seeding rows. High initial cost of tape drip irrigation is the most important factor preventing this system from spreading. Since the amount of applied tapes in the first sowing pattern, 40-60 cm, is less than the second sowing pattern, its costs are less. Therefore, sowing patterns with row seeding distances of 60-40 cm and placing tapes every other rows is recommend for cropping under tape irrigation system.

The aim of this study was to investigate the effect of tillage methods to obtain suitable seedbed for monogerm seed. Therefore, a split plot experiment based on a randomized complete block design (RCBD) with three replicatians was conducted at Darab station of Fars province. The main plot was seedbed prepration at two levels including fall and spring season. Subplot included 1) Moldboard plow at depth of 30-35 cm + Disk; 2) Moldboard plow at depth of 30-35 cm + Rototiller; 3) Chisel plow at depth of 30-35 cm + Disk; 4) Chisel plow at depth of 30-35 cm + Rototiller; 5) Subsoiler at depth of 30-35 cm + Moldboard plow at depth of 25-30 cm + Disk; 6) Subsoiler at depth 30-35 cm + Moldboard plow at depth of 25-30 cm + Rototiller. Parameters such as soil bulk density, soil cone index, percentage of germination, germination rate index, and yield and quality were measured. The results indicated that the effect of using tillage implement in fall season on bulk density and cone index was significantly different from that of spring season. Percentage of germination, germination rate index and yield increased by using the tillage implements in fall compared with spring season. Results indicated that three factors including application time, tillage implements and depth can be effective on the measured parameters. Moldboard plow at depth of 30-35 cm in fall season along with rototiller produced higher percentage of germination (94.42%), germination rate index(4.93%), purity (82.68%), root yield (81.81 tha-1) and while sugar beet.

One of the most important goals of sugar beet cultivation is to achieve high seedling emergence and establishment under water deficit conditions. In this experiment irrigation of the seed bearing plants was cutoff in four periods of 750, 1000, 1250 and 1500 GDD after schtechlings were planted and the seeds were formed and grown under water stress. The experiment was carried out as a randomized complete block design with four replications. All treatments were harvested simultaneously and seed yield and seed physical quality characters were determined. In the second step, germination qualities of treatments were determined under 0 and -12 bar osmotic potential in four replicates. Results showed that seed yield of the last irrigation cutoff (1500 GDD) was 7 times more than that yield of the first irrigation cutoff (750 GDD). Standard seed size and germination were increased by postponing irrigation cutoff. Root length was affected more than stem length by the irrigation cutoff time so that, postponing irrigation cutoff up to days before harvest root and stem length 13 and 50%, respectively.

Beet cyst nematode (Heterodera schachtii Schmidt). Spreads extensively in different regions of sugar beet cultivation, and therefore many efforts are accomplished to prevent decrease of sugar and root yield caused by the disease. The most appropriate control method of this disease is improvement of resistant varieties. Wild species of procumbentes in Beta are very important because they contain resistance genes against different diseases including beet cyst nematode. Ten-mer primers and specific sequences were selected to identify DNA molecular markers linked to beet cyst nematode resistance genes. For this purpose, at first, segregating populations for resistance genes were selected and after seed sowing in pots in greenhouse, seedlings were inoculated with 1000 nematode larva several times. Resistant plants (with lower than 10 cysts) and susceptible plants (with less than 10 cysts) were identified and divided to two groups. In the next step, RAPD-PCR, finger printing of the samples and comparison the DNA banding pattern of the two groups was done by using selected primers such as: OP-X-02, OP-X-15, OP-G-02, OP-D-13, OP-B-11, OP-Y-10 and Sat-121 specific primers and the oligonncleotides TGAACACCTTTCAAAT (forward) and CGTAAGAGACTATGA (Reverse) and one hundred primers from the operon kits. After calculating of correlation between resistance plants and the presence of special DNA band, OP-D-13 and Sat-121 molecular markers were identified to be linked to resistant genes against beet cyst nematode. In conclusion, these two molecular markers can be used for screening of resistant plants in laboratory conditions.

In order to study the impacts of mechanical (using cultivation), chemical (using herbicides) methods and their integration in controlling broadleaf weeds in sugar beet fields, this experiment was carried out as a randomized complete block design with 4 replications in Mahidasht-Kermanshah in 2006. In this experiment, 9 different treatments consisting a mixture of post-emergence herbicides phenmedipham + desmedipham + Ethofumesate and Triflusulfuron Methyl with Sittogate combined with cultivation and 2 check treatments with and without control of the weeds were investigated. The results indicated that cultivation treatment accompanied by Triflusulfuron Methyl reduced dry weight of weeds by 54.91% and showed 100% control of Amaranthus spp. In comparison with control treatment. Cultivation treatment combined with a mixture of phenmedipham+desmedipham+Ethofumesate and Triflusulfuron Methyl with Sittogate increased the sugar beet root dry weight by 159.89% and caused 100% control of the density of Conringia orientalis. Phenmedipham+desmedipham+Ethofumesate plus Triflusulfuron Methyl with sittogate treatment increased root yield by 121.86% compared to the check. In conclusion, the highest root yield was obtained in the cultivation treatment combined with phenmedipham + desmedipham+Ethofumesate, a mixture of phenmedipham + desmedipham + Ethofumesate and Triflusulfuron Methyl with Sittogate and cultivation treatments in sugar beet.

A field experiment was conducted to study the spatial relationships between weed seed bank and population and their distribution models in sugar beet crop (Beta vulgaris) in 2009 at Motahari Agricultural Research Station of Karaj. Sampling from seed bank before sugar beet drilling and weed population in three stages during the growing season were done using square (50*50 cm) and rectangle (25*100 cm) frameworks. Seed and plant frequency of each weed species were recorded in the both frameworks. Geostatistics technique was used to investigate the local structure of the weeds and dynamic of the spots. Amaranth, lambsquarter and narrow-leaf weeds were the prevalent weed species in the field. Semi-variogram analysis showed a range of influence from 0.24 to 141.9 m depending on weed species and sampling stage. The highest range of influence belonged to amaranth, especially in the second stage of seedling sampling. Lambsquarter had a lowest range of influence between all weeds. The highest nugget effect (1.671 and 1.308) was observed for amaranth (at second sampling from seedlings) and narrow leaf-weeds (at the first sampling from seedlings), respectively. This led to weak local correlation for amaranth and narrow-leaf weeds. Strong local correlation was recorded for seed and seedling of lambsquarter at all sampling stages. Spot distribution of weeds was confirmed by local distribution maps. Spots structure changed during the growing season. Results suggested that weed local distribution could improve management decisions and comprehension of dynamic of weeds populations.

The sugar beet moth, Scrobipalpa ocellatella Boyd. (Lep.: Gelechidae(is the specific pest of beet. The aim of the present study was to identify the Parasitoids of the moth. In this regard, sampling was conducted in Fields of Khorasan-e-Razavi Province during 2010 from early July until October. Larvae and pupa were collected along with tubers of sugar beet and then were reared under controlled conditions, 25±2°C, 65±5% Rh and 14L:10D until the emergence of parasitoid adults. Tubers were investigated daily and emerged parasitoids were collected. These parasitoids were put in alcohol 75°. In this study two species of larval parasitoids were collected and identified including Bracon intercessor Nees and Microchelonus subcontractus Abdinbekova and both of them belong to family Braconidae. B. intercessor is larval parasitoid and M. subcontractus is larva-pupal parasitoid. Paratype samples of the collected parasitoids are maintained in Laboratory of Entomology, Shahed University

Production is hard to achieve by increasing cropping area due to limited water resources. So, increased yield per unit area may be the solution to increase production. Investigating productivity of production factors is very important in this context. The objective of this study is to measure the productivity of production factors in sugar beet production in Fars province. The data needed for the study was gathered by completing questionnaires among 65 sugar beet growers of Fars province in growing season of 2008. The polynomial production function of order three was used to estimate the applied inputs productivity. The results showed that marginal productivity of the inputs including irrigation times, hired labor, animal manure, phosphate fertilizer, poison and cropping area are 385, -28, -0.4, 14, 2574, and -1253, respectively. It was also found that 97.1 percent of the farmers have overused animal manure and the corresponding figure for water was 61.8 percent. Reduction in labor and animal manure use is recommended.

Sugar beet as an industrial crop plays a main role in satisfying domestic demand of sugar. Study on the production efficiency of sugar beet is important because this is a factor that influences production without additional cost. In this study, Data Envelopment Analysis approach (DEA), was implemented to calculate technical, administrative and scale efficiency of sugar beet production. Also optimum level of inputs was determined. Data was collected from 60 questionnaires filled by sugar beet producers in 2009-2010. Results indicated that average of technical, administrative and scale efficiency is equal to 89.6%, 70.5% and 79%, respectively. Also, fertilizer, labor and seed were used more than optimum level whereas herbicide and water were implemented less than optimum level