Seed and Plant
Year:2002 | Volume:18 | Issue:2|Papers Count:11

In order to find a convenient crop rotation in West Azarbaijan dryland areas, field studies were conducted during 1991-1996 to compare and evaluate the existing 2-yr crop rotations including sunflower (Helianthus annus L.) - wheat (Triticum aestivum L., c.v. Sardari),chickpea (Cicer arientinum L.) - wheat and fallow - wheat. The experiments were undertaken on a silty clay soil (silt 48.2%, clay 42.4% and sand 9.4%), with OC = 0.88%, P (available) = 4.8 ppm, K (available) = 350 ppm and pH = 7.9 in Orumieh (West Azarbaijan) in dryland conditions. A randomized complete block design with 4 replications was used. Combined analysis results showed that there is no significant differences between different crop rotations. Wheat grain yields were 1.83, 1.78 and 1.82 t ha-1 in rotation with chickpea, sunflower and fallow, respectively. The effect of year was significant so that maximum yield derived from first year (2.02tha-1) and minimum yield from second year (1.65tha-1) Yield components analysis such as spike length, seed number per spike, TKW and harvest index showed no significant difference between crop rotations but effect of year was significant in all of these characters.

In order to increase the efficiency in breeding of advanced cultivars, the morphological traits that are effective in enhancement of kernel yield, should be identified and used as selection criteria. Because of that, a study was carried out on 567 bread wheat genotypes together with two check cultivars Karaj 1 and Sardari. Experimental design was augmented. To increase chance of seed-germination, one irrigation was done. Analysis of variance indicated non-significant difference between blocks for all traits. Results of correlation analysis showed that most of the traits had positive and significant correlation with plant kernel yield. By stepwise regression analysis, seven traits entered to the model which verified 98.4% of yield variation. Path analysis for plant kernel yield indicated that number of kernels per plant, and spike kernel yield had the most positive and direct effect and number of kernels per spike had the most negative and direct effect on plant kernel yield. Therefore, in this study number of kernels per plant and spike kernel yield were determined as the best selection criteria for improvement of plant kernel yield in drought stress condition.

A Study was conducted to investigate the relationship between seed vigor and field performance in chickpea. Two cultivars (Jam and Kaka), were used at two locations (The khalat-Pushan Laboratorial Centre and Research Station, Faculty of Agriculture, Tabriz University) in 1977. The seeds of two Cultivars were divided into three groups from which one group was considered as the non-deteriorated or Control (V1) and the other two groups were artificially deteriorated by the rapid aging test, at 40 °C, for 15 and 20 days respectively (V2,V3).Therefore, there were three various vigor levels for each cultivar, (V1,V2,V3).Electrical conductivity of leaked material form seeds, percentage of the viable seeds, percentage of the normal seedlings, speed of germination, and average dry weight of the seedlings were measured for each seed mass. For field study, seeds were sown in a split-plot experiment factorial with R.C.B design, in three replications and percentage and speed of the seedling emrege were measured. During growth season, the other traits were measured, as: percentage of green cover, time to flowering, time to maturity, harvest index, yield components and final yield. Results showed that in all laboratorial traits, vigorous seeds (V1) had significantly better, performance than deteriorated seeds (V2,V3).Correlation between studied traits, showed that among the seed vigor tests, electrical conductivity test and the speed of germination were significantly correlated with seed yield. Therefore seed vigor tests, have a considerable ability for prediction of chickpea performance.

In order to determine the genetic control of yield and yield components in maize, generation mean analysis of cross of two inbred lines B73 and K18 using P1, P2, F1, BC1 and BC2 generations was conducted in year 2000 in Karaj. A randomized complete block design in three replications was used for this study. Analysis for grain yield showed the additive and dominance and also, some epistemic effects in this trait. For 1000 kernel weight and number of rows per ear, dominance effects were more important than additive. There are high dominance effects for number of kernels per ear row, but, also negative additive effects were presented for this trait. High degree of dominance for grain yield and kernel depth showed the importance of dominance and over - dominance effects of genes for controlling of these traits.

In order to estimate heritability of seed yield and yield components in rapeseed diallel cross method was attempted. The 28 genotypes including 21 F2 progenies and parents were grown under two irrigation regimes (drought stress and normal) in split plot design with two replications. The results showed that variance of genotype was significant for yield and other traits, therefore there were high genetic diversit among genotypes. Diallel analysis showed both additive and non additive genes effect for yield in both conditions. The number of pods/plant in drought stress was similar to yield in the non- stress condition and it was considered by non-additive effects of genes. The data also showed heterosis for seed yield in both growing conditions Combined diallel analysis indicated that additive variances was important for seeds/po and seed weight, whereas non-additive effect for branches/plant. Broad sense heritability was high for all traits in both conditions, whereas narrow sense heritability varied from low to high in both conditions. Among yield components, seed weight and seeds/po had high narrow sense heritability under drought stress. It was concluded that recurrent selection would be more effective in improving yield in both growing conditions.

In order to assess the effects of row space and plant density on silage yield and morphological characters of corn, an experiment was carried out in Karaj for two years (1999-2000), using a randomized complete block design in split plot arrangement with three replications. Three row spaces (50, 60 and 75 cm) were considered as main plots, and five plant densities (70, 80, 90, 100 and 130 thousand plants per hectare) as sub plots. The results showed that the effect of year was significant at 1% level. Silage yield, ear yield and morphological characters of corn were affected by row spacing and plant density. Effect of row spacing on silage yield, plant height, stem diameter and ear diameter were significant. The highest silage yield and ear yield of 72.52 and 23.56 tha-1 were obtained from 50 cm row space respectively. Effect of plant density on silage yield, ear yield and all morphological characters was significant. The highest silage yield and ear yield of 69.90 and 23.59 tha-1, were obtained from 130 thousand plants/ hectare, respectively, but comparing means of interactions for higher silage yield and ear yield, plant density of 80 thousand plants per hectare and 50 cm row space could be recommended for the region.

Eleven advanced wheat lines (Triticum aestivum), produced by Seed and Plant Improvement Institute were evaluated for resistance to Russian wheat aphid (Diuraphis noxia). Quantitative damage ratings, based on the amount of leaf curl and chlorosis showed that five of the lines had higher levels of resistance to the aphid. These lines showed significantly lower leaf curl in comparison with c.v. Sholeh as a susceptible control. Additional tests to determine the mechanisms of resistance were performed with these five lines. Various levels of antixenosis, antibiosis and tolerance were exhibited in the lines. In antixenosis test, number of aphids on all lines was significantly lower than c.v. Sholeh, 24, 48 and 72h after release. In antibiosis test, fecundity and daily nymphet production were significantly lower in these lines than susceptible control. In tolerance test, percentage of damage (plant height reduction) was significantly lower in C-A/23 and C-A/11 lines than in Sholeh. Plant resistance index (PRI) was 5.27 and 4.78 in C-A/23 and C-A/15, respectively, compared to 1.00 in c.v. Sholeh. These results indicated that lines C-A/23 and C-A/15 are more resistant than the other nine lines.

In order to study correlation among seed and oil yield and their components through the path coefficient analysis method, an experiment with 100 safflower genotypes was conducted at the Research Farm of Seed and Plant Improvement Institute, Karaj in 1997. The experimental design was a 10 x 10 simple lattice. The results showed that there was good agreement between phenotypic and genotypic correlations. For most characters, genotypic correlation coefficients were higher than phenotypic correlation coefficients and there were highly significant positive correlations between biomass and number of capitula / plant with seed yield. Stepwise regression for seed and oil yield indicated that four traits including biomass, number of capitula / plant, number of secondary branches entered to model. The results of path coefficient analaysis revealed that increase of oil yield was primarily associated with increasing seed yield which was affected by biomass and number of capitula / plant.

The present investigation was carried out to study soluble proteins and antioxidant enzymes changes in wheat affected by salt stress. Six Iranian wheat cultivars and a line, differing in salt tolerance, were treated in hydroculture media with four different concentrations of NaCl (0, 50, 100 and 150mM). The young leaves and roots were harvested. The soluble leaf proteins and root enzymes were treated by Tris-HCl buffers for electrophoresis analysis. There was no clear evidence for a leaf soluble protein, corresponding to salt tolerance, nevertheless, solely the density of 32 and 56 kilodalton polypeptide bands in Mahdavi and Chenab cultivars showed some increase. However the activity of peroxidase and catalase which were increased in roots, suggesting that the salt stress induced the activity of antioxidant defence system, due to the presence of active oxygen radicals.

In order to study the effect of planting date on the yield of early maturity potato cultivars in autumn cultivation in Khuzestan province an experiment was conducted for two years (1997 and 1998)at Behbahan Agricultural Research Station. The experimental design was a strip plot in randomized complete block design with three replications. Cultivars (6 cultivar) were considered as horizontal plots, and planting date (5 planting dates) as vertical plots. In the first year (1997), cultivars Ajiba, Marfona, Timate, Stetose, Hertha and MNlO5 were planted in six dates of Sep. 29, Oct. 8, Oct. 23, Nov. 7, and Nov. 22. In the second year (1998) Ajiba, Marfona, Timate, Bona, Concorde and Romano were planted in Sep. 15, Sep. 23, Oct. 8, Oct. 23, and Nov. 7. In the first year frost occurred in Jan. 14, and all plants were killed, but in the second year, with no frost, plants continued to grow until the mid February. Analysis of variance on yield data showed that differences among cultivars, planting dates and cultivar x planting date interactions were highly significant in two years of experiment. According to the obtained results, the best planting date for potato in autumn cultivation in Khuzestan is the early October and the best cultivar is Ajiba.