نشریه علوم آب و خاک (علوم و فنون کشاورزی و منابع طبیعی)
پیاپی 1 (بهار و تابستان 1376)

In order to determine the effects of number of irrigations on stages of development, yield, and yield components of cumin, an experiment was conducted in 1993 - 94 growing season with a randomized complete block design and four replications. The location of the experiment was Isfahan University of Technology Research Station in Shervedan Field. The irrigation treatments were: I1- Irrigation after planting I2- Irrigation after planting and at the stage of full standing of plants I3- Irrigation after planting, full standing of plants, and anthesis and I4- Irrigation after planting, full standing of plants, anthesis, and beginning of grain filling stage. The stages of development (from emergence to anthesis) occurred simultaneously in all treatments. However, the water deficit in I1 and I2 caused the plants to reach their physiological maturity 5 days sooner than the other two treatments. The time intervals between anthesis and physiological maturity in I4 and I3 treatments were 12 days and 5 days longer than those in the other two treatments, respectively. The grain yield of I1 and I2 were approximately 60% of I3 and no significant difference was observed between the grain yields of I1 and I2 treatments, nor between I3 and I4 treatments. The grain yields in I3 and I4 treatments were about 1742 and 1800 Kg/ha, respectively. The number of umbels per plant, the most important grain yield component, was greater in I3 and I4 than the other two irrigation regimes, but the number of seeds per umbel and 1000-seed weight of I3 and I4 were lower than that in I1 and I2 treatments.

In order to find suitable cultivar and N-topdress rates in corn planted after wheat harvest, a field experiment was conducted in Isfahan University of Technology Experiment Farm located at Shervedan, Falavarjan in 1994. The experiment design was a split plot with a randomized complete block arrangement and four replications. Main plots were four N-topdress rates (0, 90, 180, and 270 kg/ha) and the subplots were three corn hybrids (S.C.I08, S.C.301, and D.C.370). N-topdress rates had no effect on the stages of plant development (50% emergence, transition, pollination and physiological maturity). Also there were no significant effects on the number of leaves per plant, LAI, plant height and plant dry weight measured at pollination stage for different N-topdress rates. As expected, plant development stages differed among hybrids except that of time until 50% emergence. Differences in the number of leaves per plant, LAI, plant height and dry weight of plant measured at pollination stage were highly significant among hybrids. D.C. 370 had the highest values for all of these characteristics. Dry matter accumulation during growing season increased as the N-topdress rates were increased for the hybrids. Also N-topdress rates x hybrid interaction was significant for biological yield. Grain yield, number of seeds per ear, 100-seed weight and biological yield were affected by N-topdress rates and hybrid. Higher grain yield of D.C. 370 can be attributed to greater number of seeds per ear. The results of this study suggest that D.C. 370 with 90 kg/ha N-topdress rate can be used after wheat harvest in Isfahan.

The relation between high molecular weight glutenin subunit alleles and flour quality traits have been studied for 117 recombinant inbred lines (RILs) derived by single seed descend to F7</sub> from a cross of Anza, a low quality cultivar, and Inia, a high quality cultivar, containing different alleles at 3 GLU-1 seed storage protein loci. RILs were classified by SDS-PAGE for the 8 possible combinations of the alleles. The allelic variation at the GLU-D1 locus accounted for most of the variation observed in SDS-sedimentation, mixing time and tolerance, and protein content. The GLU-D1 allele encoding the subunits 5+10 was superior to its allelic counterpart, encoding 2+ 12. All three loci had significant single locus additive effects for SDS-sedimentation volume and mixing tolerance. The additive effects of GLU-D1 locus on mixing time and protein content were also significant. The epistatic additive effects were mostly negative and with the exception of αAB</sub> and αAD</sub> for SDS-sedimentation volume were not significant.

This experiment was carried out to determine the relationship of plasma triglycerides and carcass dry matter with abdominal fat. One of the problems of broiler is carcass fatness, especially abdominal fat due to rapid growth of broilers which is not the consumer preference. Six hundred one-day-old commercial broiler chicks (Lohman) were divided into 40 groups, 15 chicks per group. Each one of the 10 experimental diets, in which barley was substituted for corn at levels of 0, 5, 10, 20 and 40%, was fed to 4 groups of chicks for 56 days. All diets were isoenergetic and isonitrogenous. Rice hulls was used to make diets isoenergetic. At days 42, 49 and 56, one male and one female were selected from each pen and after blood sampling, the birds were killed, eviscerated and percentages of carcass and amount of abdominal fats were measured. Blood samples were used to determine plasma triglycerides, cholesterol and total lipids. The results showed that increasing abdominal fat reduced carcass moisture content. Correlation between abdominal fat and plasma triglycerides was positive and significant (p<0.05). Correlation between abdominal fat and carcass moisture was negative and significant (P<0.01). The regression equations indicated that abdominal fat can be estimated from plasma triglycerides and carcass moisture content. The equations also indicated that using several parameters for estimating abdominal fat is better than single parameter estimation.

In this study, conducted in Isfahan region over a period of two years, six oilseed sunflower cultivars named Record, Venimek 8931, Chernianka, Zaria, Perdovik and Mehr hybrid were investigated in a split-split plot design. These cultivars were planted on March 29 and April 29, with and without the presence of pollinator insects. The results showed that the yield of different cultivars were significantly different (p<0.01). The planting date of March 29 caused a higher yield than that of April 29. Also the presence of pollinator insects during the bloom increased the amount of yield in all cultivars planted on both dates. Venimek and Record cultivars planted on March 29 with the presence of pollinator insects during the bloom produced the highest, i.e. an average of 3910 and 3821 kilograms of seeds per hectare and Chernianka with an average of 2944 kilograms of seeds per hectare had the lowest amount of seed. In this study, Record and Venimek cultivars in the first place and then Mehr hybrid planted on March 29 with the presence of pollinator insects during the bloom were better than the other cultivars in terms of attractiveness to honeybees, yield per hectare, seed hollowness percent, weight of 1000 seeds, germination percentage, speed of germination and the amount of oil production.

Short-term changes (5 years) in canopy cover, species composition and forage production were studied under protection from grazing and grazed condition in 19 range sites in Fereydan region, Isfahan province. In this study, density, canopy cover and forage production data were obtained from quadrates inside and outside exclosures in the spring of 1983. These parameters were studied again in 1988 and compared with the previous data. Results indicated that species diversity in these range sites was relatively high up to 212 plant species were identified. Sixteen, 8.5 and 75.5 percent of these species were classified into I, II and III palatability classes respectively. After five years, comparison of inside and outside exclosures indicated an increase in the density of species of I, II and III palatability classes by 138.8, 120.8 and 51.5 percent inside exclosures, respectively. Density of all species had increased by 62 percent as a result of 5-year protection from grazing. Species composition data as canopy cover were used to construct 3 dendrograms to investigate the similarity among range Sites. Assuming 32% similarity as the threshold level, 19 range sites were classified into 10 vegetation types in 1983. After 5 years, these vegetation types decreased to 8 and increased to 11 under protection from grazing and grazed conditions, respectively. The average forage production inside exclosures was almost twice as much as in grazed sites (600 Vs. 315 kg/h). Three groups of range sites were recognized according to the time requirement for rehabilitation by grazing protection. The first group was improved considerably by the end of the 5-year protection Period. The second group improved relatively within five years of grazing exclusion. The third group did not improve by 5-year grazing protection and needed much longer protection period or some other range rehabilitation practices.