Morphological and oil content variations amongst Damask rose (Rosa damascena Mill.) landraces from different regions of Iran

Forty landraces of Damask rose were collected from 28 provinces (13 origin sites) in Iran and evaluated to determine the diversity among them. The investigated characters were: flower weight, flower diameter, peduncle length, number of petals, number of stamens and oil content. Pearson's coefficients showed that number of petals was positively correlated with flower weight (r = 0.642) and number of stamens (r = 0.630), while its correlation with peduncle length was negative (r = −0.53). A negative correlation was obtained between oil content and number of stamens (r = −0.60) which is useful for indirect selection of landraces with low number of stamens and therefore high amount of oil content. Cluster analysis based on five botanical characters and oil content separated the origin site 12, which included Guilan, Mazandaran and Golestan provinces with a specific climate condition of temperate humid, from other origin sites. This distinctiveness was already confirmed by the bi-plot of the principal components. The distribution of Damask rose landraces provided useful information for the future collection and for the genetic resource management in these origin sites.     

The effects of irrigation regimes and nitrogen rates on some agronomic traits of canola under a semiarid environment

This study was aimed to investigate dual effects of irrigation regimes and N fertilizer rates on some agronomic traits (with emphasis on yield qualitative and quantitative characteristics) and finding optimized irrigation level and N application rate for two canola (Brassic napus L.) cultivars. For this purpose, two variety of canola (Zarfam and Modena), four irrigation regimes including 30%, 45%, 60% and 75% (I1-I4) of maximum allowable depletion (MAD) of available soil water (ASW) and four nitrogen rates (viz. 0, 90, 180 and 270 kg N ha⁻¹ (N1-N4) were involved in Karaj, Iran for two successive years (2007-2008). Our results revealed special fertilizer threshold for each irrigation regime in respect to seed yield. Response rate to fertilizers was ceased in lower fertilizer rates by prolonging irrigation. The response rate showed a decrease of 15.4%, 17.2% and 30.7% in I2, I3 and I4 in comparison with I1, but I2 response to fertilizer ceased in higher N rate as N_critical (189.8 kg N ha⁻¹). This implies that I2 improved response of canola cultivars to N fertilizer, which was accompanied by its higher WUE. Also, all estimated N_criticals for all irrigation levels were higher than the current recommendation of 130 kg N ha⁻¹. This show the capability of increasing canola cultivars yield in study region by reasonable increasing of fertilizer rate (decreasing gap between recommended N rate and estimated values) in advisable irrigation regime (I2). Cultivars tended to respond similarly to irrigation and nitrogen for seed yield in both years, but Zarfam was more efficient than Modena in respect to response to diverse treatments.     

Use of a polymerase chain reaction assay to detect and differentiate two strains of Haemobartonella felis in naturally infected cats

OBJECTIVE: To develop a polymerase chain reaction (PCR) assay that detects and differentiates the Ohio strain of Haemobartonella felis (H. felis-OH) and the California strain of H. felis (H. felis-CA) and to apply the assay to blood samples from cats with and without suspected haemobartonellosis (suspect and control cats, respectively). SAMPLE POPULATION: 220 blood samples were examined; 82 were from suspect cats, and 138 were from control cats. PROCEDURE: A PCR assay was designed to detect and differentiate H. felis-OH and H. felis-CA. RESULTS: On the basis of PCR assay results, the overall prevalence of H. felis infection was 19.5% (43/220). Suspect cats (28.0%; 23/82) were significantly more likely than control cats (14.5%; 20/138) to be H. felis infected. Significantly greater numbers of suspect cats were H. felis-OH infected (12.2%, 9/82) or H. felis-OH and H. felis-CA infected (4.9%, 4/82) than control cats (0% [0/138] and 0.7% [1/138], respectively). Significantly more anemic cats were H. felis-OH infected (14.3%; 4/28) or H. felis-OH and H. felis-CA infected (7.1%; 2/28) than nonanemic cats (2.3% [3/128] and 0.8% [1/128], respectively). The PCR assay was more accurate than cytologic examination for detection of H. felis. CONCLUSIONS AND CLINICAL RELEVANCE: Haemobartonella felis infections are more common in cats than previously recognized. Haemobartonella felis-OH is apparently more pathogenic than H. felis-CA. The PCR assay is more accurate than cytologic examination for detection of H. felis infection and is an effective clinical tool for the detection and differentiation of both H. felis strains known to infect cats.     

Water stress effects on growth, development and yield of opium poppy (Papaver somniferum L.)

The effects of pre-anthesis water deficit and cycle length were examined in Papaver somniferum L., cultivated for alkaloid production, in two locations in southern Spain. The vegetative period was shortened by extending the photoperiod through supplemental lighting in the field, while water deficit in pre-anthesis was induced by avoiding irrigations and installing rain shelters. The treatments were: IN (irrigated-normal photoperiod), IL (irrigated-hastened flowering), DN (water deficit in pre-anthesis-normal photoperiod) and DL (water deficit in pre-anthesis and hastened flowering). The artificial photoperiod hastened the flowering by 15 and 21 days, for irrigated and deficit treatments respectively. Seasonal evapotranspiration (ET) ranged from 398 (DN) to 505 mm (IN). There was evidence of root water uptake deeper than 1.5 m. Stomatal conductance was reduced (16%) during water stress, and did not recover in post-anthesis after resuming irrigation. Head yields (capsule + seeds + 7 cm stem) ranged between 3.8 and 4.3 t ha⁻¹; water deficit and short vegetative period both reduced the biomass accumulated, although the effect on yields in these treatments was counterbalanced by a higher harvest index. Early flowering had a detrimental effect on alkaloid concentration in the capsule. Alkaloids yield ranged between 27 and 37 kg ha⁻¹. Water use efficiency (WUE) ranged between 0.78 and 0.96 kg m⁻³ ET for yield and between 63.4 and 73.7 g m⁻³ ET for alkaloids. Water stress increased slightly the Water Use Efficiency. A shorter vegetative phase had no effect on WUE for biomass or yield, but decreased the WUE for alkaloids production.     

Corn yield response to crowding stress and cropping season

Corn (Zea mays L.) is planted in two seasons per year in northern Iran (mid-April as a main crop and mid-June as a second crop). The main objective of this study was to determine whether corn yield response would differ between these two seasons and different plant populations. Two field experiments were conducted at the Agricultural Research Center of Golestan – Iran in 2007 and 2008 at different planting densities. The results showed that the values of grain yield and most traits were significantly lower in the second season. Maximum grain yield was observed at planting densities of 6.5 plants m^?2 in the first season, whereas in the second season grain yield was the same for planting densities between 2.5 and 12.5 plants m^?2. Based on the second-year experimental results, the following functions were fitted to show the relationship between yield ha^?1 (Y) and planting densities (X) for the first and second seasons, respectively: (Y = ?167.6X ² + 2672.2X + 511.77; R ² = 0.992) and (Y = 1200.1 ln(X) + 2924.4; R ² = 0.935). This study found that the optimum plant population was 6.5 plants m^?2 under low heat stress, and should be reduced to 2.5–4.5 plants m^?2 under heat stress conditions.     

Effect of soil water management and different sowing dates on maize yield and water use efficiency under drip irrigation system

A 2-year field experiment (2012–2013) was conducted to evaluate the yield and water use efficiency (WUE) response of maize (Zea mays L.) to different soil water managements at different sowing dates. The experiment included three sowing dates (22 June, 6 July and 21 July) and four irrigation regimes based on maximum allowable depletion (MAD) of the total available soil water (TAW). The irrigation treatments were marked by I₁ to I₃ as 40%, 60% and 80% MAD of TAW, respectively, and with no irrigation. The results showed that grain yield reduced when planting was delayed in both years, ranging from 6105 to 4577 kg ha^?1 in 2012 and from 7079 to 5380 kg ha^?1 in 2013. However, WUE increased when planting was delayed from 22 June until 21 July. Also the highest grain yield was observed in the first irrigation treatment (MAD = 40%) in both years, and the highest WUE was obtained in the second irrigation treatment (MAD = 60%) with 1.64 and 1.61 (kg m^?3) in 2012 and 2013, respectively. These findings suggest that delay in planting date and the use of MAD = 60% treatment in Mediterranean-type region such as Golestan, Iran, can be useful in saving water that is highly important in such regions.     

Quantification of the cardinal temperatures and thermal time requirement of opium poppy (Papaver somniferum L.) seeds to germinate using non-linear regression models

The response of plant development rate (including germination rate) to temperature might be described as a non-linear function. We compared 3 non-linear regression models (Dent-like, segmented and beta) to describe the germination rate-temperature relationships of opium poppy (Papaver somniferum L.) over 6 constant temperatures to find cardinal temperatures and thermal time required to reach different germination percentiles. Two replicated experiments were performed with the same temperatures. An iterative optimization method was used to calibrate the models and different statistical indices (mean absolute error, coefficient of determination (R²), intercept and slope of the regression equation of predicted vs. observed germination rate) were applied to compare their performance. The segmented was found to be the best model to predict germination rate (R² = 0.92, MAE = 0.0011 and CV of 1.4-3.6%). Estimated cardinal temperatures were similar for different germination percentiles (P < 0.05). Base on the model outputs, the base, the optimum and the maximum temperatures for germination were estimated as 3.02, 27.36 and 36.31 °C. The thermal time required to reach 50 and 95% germination was 57.27 and 87.55 degree-days, respectively. Model predictions of the time required for seed germination agreed reasonably well with the observed times (MAE = 0.56 day, R² = 0.887). All model parameters may be readily used in crop simulation models.