JWSS - Journal of Water and Soil Science

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Due to the need for new fumigants to control insects that attack food commodities, the toxicity of acetone was determined on some species of stored pest insects in Urmia University in the year 2000. In empty space tests, the LC₅₀ values of acetone for Oryzaephilus surinamensis (L.), Callosobruchus maculatus (F.), Tribolium confusum (Duv.) and Sitophilus granarius (L.) were 15.40, 15.51, 17.55 and 18.26 μl/liter, respectively. The experiments of acetone penetration to wheat mass revealed that the application of acetone in headspace led to the penetration of acetone vapours into the wheat mass and killing the S. granarius and T. confusum had been concealed in interkernel space. The comparison of LC₅₀ values of empty space tests with LC₅₀ values of penetration experiments revealed that the increase in penetration toxicity was 8.63 fold for S. granarius. A similar trend was observed for T. confusum adults. In hidden infestation tests, the application of acetone to the headspace resulted in destroying the developmental stages of S. granarius concealed in wheat and achieved 75% mortality at a dose of 160 μl/liter during seven weeks. Acetone showed no deleterious effects on the germination and vigor of wheat seeds.

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A total of 25 advanced rapeseed (Brassica napus L.) varieties were evaluated under cold weather conditions using Randomized Complete Block design (RCBD) with four replications in Dr. Nakhjavani Agricultural Research Station, 35 km North-East of Urmia the capital of West Azerbaijan province in 2000-2001. The results showed significant differences among the varieties (P ≥ 0.01) for all the phenological stages including days to germination, days to rosette completion, days to initiation of stem elongation, days to flowering initiation, pod formation stage and days to maturity. The spring varieties Sarigol (PF7045/91), Hyola 42 and SYN1 and autumnal varieties Alice, Eurol, Fornax, VDH 8003-98, Consul, Licord and Zarfam (Regent× Cobra), showed early maturity. On the other hand, Mohican, Olara, Colvert, L-1 and Akamar were late mature varieties. In fact, the most prolific varieties, DP.94.8, Zarfam (Regent ×Cobra) Cocktail, Consul and SLM046 (control variety) had the highest ability survive in the cold conditions and they completed their rosette stage sooner than the other varieties. There was positive and significant correlation between duration of pod formation stage and seed yield. Maturity date of varieties was positively and significantly correlated with harvest index, number of seed per pod, days to germination, days to rosette completion, days to stem elongation, days to flowering, and days to pod formation. Negative and significant correlations were found between days to maturity and duration of flowering and pod formation stages. It can be concluded that delay in initiation or completion of each growth stages could delay maturity of the rapeseed varieties.

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To evaluate the effect of plant density and detopping on grain yield, protein content biological yield harvest index, growth indices, number of cob in each plant, No. of row per ear, No. of grain in each row, thousand seed weight of corn (Zea mays L. ar. SC 704), an experiment was conducted at the experimental statues of Research Center of Uremia Agricultural College in 2004. The Treatment design was split plot in randomized complete block design with four replications. The main plots included plant density at three levels (53000, 66000, and 88000 Plants/ha) and the subplets comprised three levels: (1) no detopping (control) (2) removing canopy only and (3) removing canopy and three leaves above the node. Analysis of Variance of data showed that both detopping treatment and plant density influenced the number of kernel per ear ,1000 grain weight, ear weight, total dry weight of biomass, seed yield and harvest index. Canopy detopping led to a marked increase in photo assimilateion import grains. The highest plant density evaluated, 88000 plants per hectare with detopping of three above leaves had the highest number of cobs per square meter. In plant density of 53000 plants per hectare and canopy detopping treatment, the number of grain per ear was greater than other densities. The efficiency of harvest index increased under corn detopping compared with control, and this increase with an increase in photosynthesis contributed to grain yield. It was concluded that major increase in grain yield under high plants density and tassel detopping was due to improvement of physiological indices.