Journal of Plant Ecophysiology
Volume:1 Issue: 2, 2009

To determine the possible effects of climatic parameters on sugarbeet seed yield, the correlation between seed yield and different meteorological parameters during 1955-2002 was determined and the parameters which had significant correlation with seed yield were fitted by multivariate models. To scrutinize the effective climatic factors, the growth period of sugarbeet seed-bearing plants (from early-April to late-July) was divided into fifteen-day intervals during planting-bolting, bolting-blooming, blooming-full bloom, full bloom-maturity and total growth period. Then, simple correlation coefficients of each period with seed yield were estimated and finally multiple regression model was fitted. The results showed that the seed yield significantly correlated with mean temperature during the first half of May (-0.591*) and first half of July (-0.584*), mean sunny hours during the first half of May (-0.544*) and first half of June (-0.550*), total precipitation during the second half of April (0.565*) and first half of June (0.624**) and total received growing degree days (GDDs) during the first half of May (-0.505*) and first half of July (-0.584*). On the other hand, sugarbeet seed yield had significant correlation with total precipitation (0.574*) during the planting-bolting period, sunny hours (-0.511*) during the bolting-blooming period and precipitation (0.526*) during the growth period.

A field study was conducted over two growing seasons to evaluate the effects of foliar application of salicylic acid (SA) at 0, 0.1, 0.5 and 1 mM rates and paclobutrazol (PB) at 0, 50, 100 and 150 mg/l rates on the growth and development of safflower cv. Isfahan in Kerman, Iran. Both SA and PB increased leaf number, total biomass, head flower biomass, lateral branches, head flower number, seed number, seed yield, single seed weight and harvest index. The effect of SA was more pronounced at 0.1 mM and increased leaf number (19%), total biomass (44%), head flower biomass (58%), lateral branches (355%), head flower number (108%), seed number (72%), grain yield (83%) and harvest index (21%) compared with the controls. PB was more effective at 100 mg/l and increased leaf number (32%), total biomass (38%), head flower biomass (49%), lateral branches (380%), head flower number (66%), seeds number (48%) and grain yield (56%) compared with control. Moreover, none of the plant growth regulators (PGRs) affected seed oil and protein content.

To evaluate the effects of meteorological factors on yield and yield components of winter rain-fed canola cv. Hyola, 20 fields were selected in Kalaleh Region, Golestan province, Iran. In addition to recording the dates of phenological stages during growth period, the traits grain yield and yield components were measured after harvest. The meteorological parameters including minimum and maximum daily temperature, minimum and maximum daily relative humidity, daily evaporation and daily precipitation supplied by Agriculture Meteorology Station of Kalaleh were estimated for the growth stages of planting-flowering, flowering-podding and podding-maturity. The results showed that grain yield had the highest negative and significant correlation with days from planting to maturity and flowering-podding (-0.549* and -0.522*, respectively) and with received growing degree days (GDDs) during growth period as well as during flowering-podding (-0.511* and -0.508*, respectively). Higher daily evaporation (-0.551*) and GDD (-0.496*) from podding to maturity significantly decreased final plant density. Among all components, grain yield had significant correlation just with pod number/plant (0.520*). Higher day (0.504*)/night (0.531*) temperature during growth period, especially during podding-maturity period (0.502*) was accompanied with an increase in grain number/pod, while longer planting-podding period decreased this component of canola yield (-0.507*).

The novel salt-tolerant cereal, Tritipyrum, is the third artificially-synthesized crop plant. The agronomic traits and grain yields of 13 primary 6x Tritipyrum lines were evaluated and compared with five modern 6x Triticale lines and nine bread wheat cultivars at Shahid Bahonar University, Kerman, Iran in a randomized complete block design. The Tritipyrum lines had higher grain yields (2.25 gr/plant) than the Triticale lines (1.97 gr/plant) and wheat cultivars (0.84 gr/plant). Although the Tritipyrum lines were late-maturity, they were shorter than the Triticale lines and wheat cultivars and superior in many characters such as penultimate leaf area, flag leaf length, penultimate leaf length and time to milky ripeness. Genotypes were divided into four groups for agronomic and morphological traits and four groups for grain yield by cluster analysis. All clusters showed significant differences for all traits and the first cluster, which comprised of Tritipyrum lines, had a higher mean grain yield than the other clusters. The results of this first large-scale trial indicated the high adaptation of Tritipyrum lines to climatic conditions of Kerman province in south-east Iran.

In order to determine the effects of plant density and planting pattern on yield, yield components and morphological traits of forage sorghum, an experiment was conducted at Agricultural Research Station of Azad University, Birjand Branch, Iran in 2003. The experiment was a factorial based on RCBD with three replications and eight treatments. Factors were plant density with 4 levels (20, 30, 40 and 50 plant/m2) and planting pattern with 2 levels (one row above furrow and two rows within furrow). The results obtained from the statistical analysis showed that the effects of plant density, planting pattern and their interactions were not significant on yield and yield components of forage sorghum but the effect of plant density was significant on the number of tiller per plant and main stem diameter. The total produced fresh forage in the plant densities of 20, 30, 40 and 50 plants/m2 was 25.8, 25.7, 25.6 and 28.6 ton/ha, respectively and the total produced dry forage in the above plant densities was 5.28, 5.35, 5.26 and 5.83 ton/ha, respectively. Increase in plant density decreased number of tillers/plant and stem diameter. In the density of 20 plants/m2 with an average of 2.3 tillers/plant the maximum and in the density of 50 plants/m2 with an average of 0.27 tillers/plant the minimum tillering were observed. The results of the research indicated that for optimum use of the short growth period of forage sorghum dense cultivation in the second cultivation in Birjand region is recommended.

In order to evaluate yield potential of different genotypes of sesame under different levels of Iron and determine the most effective traits on yield, an experiment was carried out as split plot based on randomized complete block design in Jiroft during 2008. Treatments consisted of three levels of iron (chelat 138) (0, 5, 10 kg.ha-1) as the main factor and genotypes of sesame (Markazi, Shahrbabak, Birjand, Dezfoul, Jiroft, Sirjan, Gorgan, Ardestan and Orzooieyeh landraces) as the sub factor. Traits such as plant height, number of stems/plant, number of pods/plant, number of pods/main stem, pod length, number of seeds/pod, 1000-seed weight, seed yield, biological yield and harvest index were studied. According to the results of analysis of variance, genotypes were significantly different for all the traits and Jiroft genotype was considered as the best one for cultivation in this region. Fe had no significant effect on the studied traits except 1000-seed weight. Since the interaction of fertilizer and genotype was not significant too, it was concluded that the fertilizer did not have effective role on the yield of the studied genotypes. Seed yield showed highly significant, positive correlation with plant height, pod length, number of seeds/pod, 1000-seed weight, number of stems, biological yield and number of pods/plant. Based on path analysis, number of seeds/pod had the highest positive direct effect on plant yield indicating that this trait can be considered as a criterion for improving seed yield in sesame breeding programs.

In order to study the effects of nitrogen and potassium fertilizers on yield and yield components of lentil under rain-fed conditions, an experiment was carried out in Agriculture Research Center of Ardabil, Iran in 2008. A factorial experiment based on a complete randomized block design with three replications was used. Nitrogen treatments included three levels (0, 25 and 50 kg.ha-1), potassium treatments included three levels (0, 30 and 60 kg.ha-1) and there were two cultivars (a local and a new cultivar named ILL180). Traits including plant height, number of branches/plant, number of filled pod/plant, pod number, seed number/plant, 100-seed weight and grain yield per unit area were measured. Analysis of variance showed that cultivars were not statistically significant regarding grain yield. Application of 50 kg N.ha-1 fertilizer significantly increased the number of secondary branches/plant, number of filled pod/plant, total number of pod, seed number/plant and seed yield. Maximum seed yield was achieved when 50 kg N.ha-1 fertilizer was applied. Potassium fertilizer had no significant effect on the above-mentioned traits.

To evaluate the effects of water deficit stress and Selenium application on maize yield and yield components, a field study was carried out in 2008 as a split-split plot design based on randomized complete block. In this study, irrigation treatments included irrigation cutoff at full flowering stage and irrigation up to the end of growth period as main plots, studied cultivars included SC700 and SC613 as sub-plots, and Selenium treatment from sodium selenite source (spraying at full silking stage) constituted sub-sub-plot. The results showed that there were significant differences between irrigation treatments and cultivars as well as Selenium levels at probability level of 99%. Means comparison of cultivars showed 46% decrease in yield under stress condition. Selenium application increased yield under water deficit stress. It also increased thousand-grain weight and grain number/ear. Thousand-grain weight and grain number/ear were affected by water stress and Selenium application. SC700 had the highest thousand-grain weight and yield. The highest leaf area index was observed at grain filling stage both in control and drought stress treatments. Selenium application decreased leaf area index, so that SC700 had the lowest leaf area.