To evaluate 8 Damask rose genotypes, an experiment was conducted during 2003-2004 at the experimental field of Research Institute of Forests and Rangelands, Tehran, Iran. Genetic variation was studied for phonological traits, such as FLOWERING date and DURATION, and morphological traits, including plant height and canopy coverage, thorn length and density, leaflet length and width, stipule size, branch angel, receptacle length and width. Simple and combined analyses of variance, mean comparison and phenotypic correlations were performed. The combined analysis showed significant differences (P<0.01) between genotypes for all the traits and for year and year x genotype interactions for most of the traits. Comparison of means classified the genotypes for FLOWERING DURATION, and also in different groups for other characteristics. Significant correlations were observed between different traits. Also the phenotypic correlation coefficient (r= 0.90) between flower yield and FLOWERING DURATION indicates a significant (P<0.01) positive relationship between these traits. According to the results of this investigation, a wide range of variation among the 8 genotypes was observed in terms of the traits under study. for an efficient breeding program, FLOWERING DURATION could therefore, be one of the useful criteria for yield selection, though more genotypes, as well as further analyses, such as yield quantity and quality are necessary to be considered.

The FLOWERING and fructification period of the Chilean strawberry (Fragaria chiloensis (L.) Duch.) is restricted to approximately 2 mo, which seriously limits the commercial development of the species. The objective of the current investigation was to identify Inter Simple Sequence Repeat (ISSR) polymorphisms associated with FLOWERING DURATION in accessions of F. chiloensis. The FLOWERING DURATION data related to 41 accessions obtained over 3 years were analyzed, and a set of 40 ISSR primers tested. Two clusters were obtained through the Partitioning Around Medoids algorithm, with 23 vs. 18 accessions, and 64.1 vs. 95.6 days of FLOWERING, respectively. FLOWERING DURATION, between the two groups, was significantly different. The years also revealed a significant effect, on FLOWERING DURATION, between the two groups. Ten of the ISSR primers tested revealed reproducible and consistent banding patterns, displaying a total of 106 putative loci, of which 79 were polymorphic. Three ISSR loci (811779, 844670, 841980) were identified owing to their significant contribution to the differentiation among the accessions. Similarly, three ISSR loci (811600, 8121180, 841980) exhibited a significant correlation with the FLOWERING DURATION variation. Locus 841980, which presented the highest level of correlation with FLOWERING DURATION, was isolated, cloned and sequenced, but it showed only a low level of homology with the relevant sequences published in the GenBank database. The identified loci showing high correlation with the FLOWERING time could help build Quantitative Trait Loci (QTL) maps for selection and improvement programs in the Fragaria sp. genus or other related species.

In the floriculture industry, the need for heat tolerant bedding plant cultivars is increasing because of the rising temperature around the world. A pot experiment was carried out to examine the impacts of four heat stress DURATIONs (0, 7, 14 and 21 days) on growth and ornamental traits to determine the relative heat tolerance of four cultivars of calendula (Calendula officinal is). Growth and development were quantified by measuring plant height, total leaf area, shoot and root fresh weight, shoot and root dry weight, time to FLOWERING, flower number, average flower size, and flower longevity. Plant height, leaf area, and shoot and root growth at 35-42°C were significantly lower than those at normal temperatures (20-30°C). Time to FLOWERING increased with temperature. Flower number, size and longevity were reduced by heat stress, so that among all DURATIONs, plants exposed to heat stress for 21d had the least mean. Longer heat stress reduced the plant height, leaf area, shoot and root growth, SPAD value, flower diameter and flower longevity of all cultivars., However, the range percentage reduction in growth and FLOWERING parameters were different among cultivars. Experiment to determine the membrane damage showed an increase in percent electrolyte leakage with exposure of plants to higher temperatures. The studied cultivars differed in their sensitivity to heat stress. The results indicated that better cell membrane stability, higher shoot and root growth, and later FLOWERING led to greater heat tolerance in ‘Indian Prince’ compared to other cultivars.

The availability of nutrients such as phosphorus in plant, in addition to plant yield increment, could increase growth rate and thus reduce plant growth period. Therefore, identification and overexpression of genes involved in nutrient uptake are the important steps to increase of yield and tolerance to environmental stresses particularly the end seasons stresses. Purple acid phosphatases, one of the most important phosphatase family, play a key role in increasing phosphorus availability in plants. In this study, the effect of knock-out and overexpression of AtPAP17 and AtPAP26 genes (two important members of Arabidopsis thaliana purple acid phosphatase family) on some physiological and phonological traits of Arabidopsis thaliana was investigated under Pi-sufficient (1. 25 mM KH2PO4) and Pi-deficient (0 mM KH2PO4) conditions. For this purpose, single and double mutant plants of AtPAP17 and AtPAP26 genes were studied in this research. To confirm the function of mentioned genes in mutant plants, transformed Arabidopsis plants containing the CaMV-35S: AtPAP17 and CaMV-35S: AtPAP26 constructs were studied as overexpressed plants of AtPAP17 and AtPAP26 genes, respectively. The result showed that biomass and phosphorus content of plants increased in single mutant plants as compared to double mutant plants under Pi-sufficient condition. Superiority of single mutant plants as compared to double mutant plants indicated a remarkable contribution of AtPAP17 and AtPAP26 genes in phosphatase compensation network. Our results showed at least one of these genes (AtPAP17 and AtPAP26) activity is essential for increasing phosphorus availability and fast growth in Arabidopsis thaliana. Also, overexpressed plants displayed a significant increase in phosphorus content, FLOWERING percentage, and biomass as compared to WT plants (Col-0). The results of this study showed that AtPAP17 and AtPAP26 genes could be important candidates for developing the plants with high ability of nutrient uptake, especially phosphorus, thereby reducing plant growth period.

Background and Objectives: Tulip flower is one of the most popular flowers in the world. This bulbous flower has about 150 species with more than 6000 recorded cultivars. In the recent years, planting of ornamental bulbous plants such as tulip has been common in many cities of Iran during Nowruz. Selection and order of the bulbs often is done based on aesthetic and FLOWERING factors. Feasibility of estimation of some aesthetic traits in tulip cultivars can be a management approach in the cities, so that if urban managers in the landscape field know the time and DURATION of FLOWERING, they can have an exact plan for the tulip planting in the Nowruz. The study of ornamental traits, FLOWERING date and DURATION of tulip flower have been studied in the different climatic and edaphic conditions. Tulip cultivars have prolong FLOWERING periods that their FLOWERING DURATION can match with Nowruz are an apocopate option to use in the urban landscape of Mashhad. One of the methods to estimate the vegetative and ornamental traits in the ornamental plants is prediction models using bulbous dimensions with other plant part dimensions or combinations of them. In the current paper the study of the date of FLOWERING and its DURATION in the several cultivars was investigated. On the other hand an attempt has been made to establish a best method for estimation of some ornamental traits in the tulip flower. Materials and Methods: In the first part of the examination, six plots including six cultivated cultivars of tulip with area of 5 m2 were prepared. Weight and diameter of bulbs were measured before planting and ornamental traits include height of flower stem, length and width of flower. Data from nearly 100 plants for each cultivar were recorded. Regression analyses of WB, DB, WB×DB, WB/DB, WB2×DB2 and WB2/DB2 versus height of flower stem, length and width of flower were done. . Among tested models (linear, polynomial, power, logarithmic and exponential) the models with highest R2 values can be used for estimating of the mentioned ornamental traits. The correlation coefficients and also constants (a, b and c) were reported. In the other part of the examination, 23 cultivars of tulip in 15 plots with area of 20 m2 were planted in the various parts of Mashhad. FLOWERING date and also the DURATION of FLOWERING from nearly 50 plants for each cultivar were recorded. Results: Results showed that the highest correlation between dimensions of bulbs (weight and diameter) with height of flower stem (R2=0. 88) was observed in weight of bulbs. Among of the tested models, the highest coefficient of correlation was obtained in polynomial equation. The calculated correlation between weight and diameter of bulbs with length and width of flower were low. In the Royal virgin cultivar, flower length with the bulb weight and also multiple of the bulb weight and diameter significantly showed a positive correlation (R2=0. 88 and R2=0. 81). In the other part of the current study, results indicated that the most of studied cultivars showed different FLOWERING dates and DURATIONs. According to the results, the most early-FLOWERING cultivars obtained from Copex, Yokohama, Happy generation and Apricot beauty. The most lately-FLOWERING cultivar of tulip in the present study was observed in Spring green. Discussion: In the first part of the study, the developed models including WB, WB×DB and WB2×DB2 that have the highest R2 levels in comparison with other models can be applied to estimate height of flower stem in most of tulip cultivars. In the second part of the study, among of the 23 cultivars, only Apricot fox, Pretty lady, Happy generation and Yokohama are advisable to plant in the urban landscape in Mashhad in order to have flower during the Nowruz.

In order to study the effects of soil textures and super absorbent polymer rates on yield of flower, corm and stigma and other growth characteristics of saffron, an experiment was conducted as factorial based on a randomized completed block design with three replications at the outdoor area of the greenhouse of College of Agriculture, Ferdowsi University of Mashhad during two years of 2010 and 2011. The experimental treatments were three soil textures in fine to coarse ranges such as sandy loam, loam, clay loam and super absorbent polymer rates such as zero, 0.1, 0.2, 0.4 and 0.8 weight percentage based on dry weight of soil. Traits including emergence rate of leaf, DURATION of FLOWERING, dry weight of corm, number and fresh weight of flower and dry weight of stigma for saffron measured and calculated. The results showed that the simple effects of soil textures and super absorbent polymer rates were significant on emergence rate of leaf, FLOWERING rate, dry weight of corm, number and fresh weight of flower and dry weight of stigma for saffron (p£0.01). The highest stigma yield with 0.94 g.m-2 was recorded in sandy loam that it was higher that loam and clay loam with 30 and 49%, respectively. By increasing in super absorbent from 0 to 0.8% enhanced dry weight of stigma. Since saffron fields in arid and semi arid climatic conditions have clay texture with relatively low moisture content, super absorbent application might increase growth and yield due to accelerating in initiation of flower harvest from saffron farm.

Proportionality of wheat cultivars growth patterns to the area’s agro climatic condition will improve crop production. The objective of this study was identifying the phenology of a wide range of wheat varieties in Iran, as well as evaluating the relationship between phenology and drought stress tolerance under late season drought stress. In this experiment, 36 wheat genotypes were studied under irrigated and drought stress conditions, at farm of the Agricultural College of Tehran University during 2010-11cropping season. Experimental design was simple lattice with three replications. Phenology, grain yield, grain number per spike and 1000 kernel weight were recorded for all cultivars. The results showed that most of the varieties which had short vegetative DURATION, subsequently had greater ability to tolerate late season drought stress. Also, under drought stress condition, wheat varieties with short grain filling period had the highest 1000 kernel weight, such as Simineh, Chenab, Stork, Moghan 3, Cross falat hamoon and DN-11.

Regulation of FLOWERING time requires the activity of various genes that are controlled by environmental and internal cues. The FLC gene plays a key role in transition to FLOWERING and suppresses FLOWERING as target gene of vernalization pathway. Vernalization is a natural adaptation to ensure FLOWERING after winter so that flowers and seeds can develop in favorable environmental conditions. In this study, identification and expression of FLC gene was investigated in rocket mustard (Sisymbrium irio). Total RNA was extracted from cotyledon leaves and cDNA was made. Specific primers were designed based on tsequence alignment of FLC homogenous genes and used for RT-PCR reaction. The identified 449 nucleotids fragment was recorded as SiFLC with accession number KT156751 in the NCBI database. Sequencing of the coding region and comparison of its putative protein (with 150 amino acids) and FLC orthologues in other plants showed their high similarity. Expression relative rate using the semi-quantitative method, in vegetative stage in young leaves, mature leaves, stems and roots was between 56-86%, which the highest (about 86%) and the lowest (about 56%) levels were observed in young leaves and stems respectively. In the reproductive stage, a decrease in expression was observed in these organs especially in leaves (about one percent). However, expression level was higher in flower buds and reached about 31%. Decreasing leaf expression in the reproductive phase indicates FLOWERING induction. FLC higher levels in flowers, after transition to FLOWERING, allows the next generation to reregulate its rate and respond to winter during vegetative phase

Introduction Sowing date is the variable with the largest effect on crop growth and its yield (Hundal et al., 1997). Planting the suitable variety at the right time results in FLOWERING phase when the risk for freeze damage is the lowest and before the onset of heat stress during FLOWERING and grain filling stages (Khichar & Niwas, 2006). Adequate soil moisture especially in dryland conditions is also important. Correctly matching the time at which growth stages of crop occur with the favorable environmental conditions is the key to maximizing growth and yield (Dadashi & Khajehpour, 2004). Thus, growers need to choose the appropriate varieties for a specific planting time for achieving the optimal FLOWERING period, which can lead to the highest possible yields...