Journal of Soil and Plant Interactions

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In order to improve quantitative and qualitative properties and vase life of rose cv. Dolcvita, an experiment was conducted in a randomized complete blocks design with ten treatments and three replications in a hydroponic greenhouse adjacent to Yasouj city, Iran. Treatments included control, spermidine (0.5, 1 and 1.5 mM), calcium sulfate (2.5 and 5 mM), spermidine 0.5 mM+ calcium sulfate 2.5 mM, spermidine 0.5 mM + calcium sulfate 5 mM, spermidine 1 mM + calcium sulfate 2.5 mM and spermidine 1 mM + calcium sulfate 5 mM. Traits such as length of flower stalk, stem diameter, flower bud diameter, fresh weight of stem, chlorophyll content and vase life were measured. Results showed that effect of spermidine and calcium sulfate on all traits, except chlorophyll content, was significant (P<0.05). The highest and lowest length of flower stalk, stem diameter and fresh weight of stem was obtained in the 1.5 mM spermidine and control treatments, respectively. The highest diameter of flower bud was observed in the 0.5 mM spermidine and 2.5 mM calcium sulfate treatments. Flower vase life in the 0.5 mM spermidine + 5 mM calcium sulfate treatment was higher than that in the other treatments. Therefore, application of 1.5 mM spermidine is recommended for improving quantitative properties and combination of 0.5 mM spermidine with 5 mM calcium sulfate for increasing vase life of rose, cultivar Dolcvita, in hydroponic system.

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In order to investigate the effects of different forms of nitrogen in nutrient solution on photosynthesis rate and quantitative properties of rose cv. Dolcvita, an experiment was conducted in a randomized complete blocks design with seven ratios of urea: NH4+: NO3- (0-100-0, 0-50-50, 0-0-100, 50-0-50, 25-25-50, 15-15-70 and 0-0-100) and three replications, in a hydroponic greenhouse which grows rose flower. The rooted plants of rose cv. Dolcvita were potted filled with perlite and cocopeat (50:50) substrates. Then, quantitative properties such as plant stalk height, bud length, diameter of bud and stem, leaf area index, vase life, fresh weight of stalk, leaf greenness and photosynthesis parameters were measured. The results showed that increasing the ammonium in nutrient solution reduced the photosynthesis rate, water use efficiency and leaf mesophyll efficiency. The highest stalk height was obtained from 25-25-50 and 0-0-100 treatments (88.3 cm and 86.9 cm), respectively. The highest fresh weight of stalk was obtained in 0-0-100 treatment. Application of 50-0-50 treatment increased leaf greenness as compared to other treatments. When ammonium was increased in nutrition solution, the vase life was reduced. The highest and lowest vase lives were obtained from 25-25-50 and 100-0-0 treatments (17.6 and 11.1 days), respectively.

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In order to identify drought tolerant strawberry (Fragaria ananassa Duch.) cultivars and investigate some of their morphological, quantitative and qualitative characteristics, a research was conducted as split plots based on randomized complete blocks design with three replications under greenhouse conditions. Deficit irrigation stress was considered as the main plot factor at 4 levels (control (0), 20, 40 and 60 percent) and subplot factor was cultivar at 6 levels (Kurdistan, Camarosa, Merak, Paros, Queen Eliza and Selva). Leaf area showed a 41.42% reduction, and number of flowers and fruits showed 90% reduction in 60% stress treatment in comparison to the control. Total soluble solids (TSS) showed an increasing trend up to 40% stress severity. As stress increased, titrable acidity (TA) showed a decreasing trend. A high heritability was observed for number of flowers and fruits, fruit weight and TSS. Considering the three-dimensional plot of STI,  and , the Kurdistan and Camarosa cultivars were identified as the most suitable cultivars in both deficit irrigation stress and non-stress conditions. So, these cultivars could be used in breeding programs in order to increase drought tolerance. According to the responses of cultivars to deficit-water stress, more leaf area, number of flowers, number of fruits number, fruit weight, and TSS, and lower TA are introduced as the selection criteria for drought tolerant strawberry cultivars.

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Genetic diversity in strawberry is low due to its asexual propagation. One method of increasing genetic diversity, as an important tool in plant breeding, is the use of gamma rays to induce mutation. In order to determine the appropriate dosage of gamma irradiation for genetic diversity creation by mutation in strawberry, Kurdistan cultivar, and to study the influence of various doses of gamma ray (zero (control), 15, 30, 60 and 90 gray) on different traits of strawbery, this research was conducted in Faculty of Agriculture, Yasouj University, in 2012-2013. Results showed that irradiated plants had a lower rates in comparison to the control plants for most of the studied characteristics, except for number of leaves, fruit sugar and anthocyanin. Leaf area, fruit length, fruit diameter, fruit fresh and dried weight, and fruit volume, shape, and juice decreased with an increase in the gamma irradiation dosage. Moreover, multifoliate and dwarfism were increased in the irradiated plants. The appropriate dosage of gamma irradiation for mutation induction in strawberry, Kurdistan cultivar, for threshold 50% plants mortality (LD₅₀) treated by gamma ray, was approximately 65-70 gray. Therefore, gamma ray intensity in the recommended limit could be used for the highest genetic diversity creation with the lowest plant mortality in strawberry breeding programs such as in fruit quality improvement.