مجله علوم باغبانی ایران
سال چهل و دوم شماره 1 (بهار 1390)

Apricot (Prunus armeniaca), palys an important role in fruit production industry in Iran. Irregular set of fruit, caused by either sterility of flower organs or incompatibility has been the main problem in apricot production over the years. In this study, it has been attempted to determine these phenomena for four apricot cvs. namely ‘Shahroodi’, ‘Nasiri’, ‘Jahangiri’ and ‘Noori’ through the methods of controlled pollination, study of fruit set (percentagewise) within three dates (10, 30, 60 days after pollination), an evaluation of pistil length and diameter, as well as study of pollen germination were carried out in Karaj climatic conditions. The experiment was conducted in the frame work of a factorial one in CRD with diallele crosses. The results of pollen germination revealed that there was not any male sterility evident in the cultivars. Three dates were considered for an assessment of fruit set (percentage wise) according to natural abscission of fruitlets. Initial fruit set for ‘Jahangiri’ was high enough, suggesting not any female sterility. The data from pistil length and diameter at ballon stage of flowers also confirmed these results. Fruit set at second stage (30 days after full bloom) showed that all the four cvs. were prone to be self-incompatible but not reciprocally cross-incompatible. ‘Shahroodi’ and ‘Nasiri’ with poor fruit set at stages 1 and 3, were considered to suffer from female sterility and embryo sac abnormality. To some extent, pollen germination test proved that none of the four examined cvs. were suffering from male sterility in the process of pollination. Interaction effect of pollen × pistil was significant showing different behaviors of pollen type for germination and growth conditions provided by different pistils. All four cultivars were self-incompatible and as for ‘Shahroodi’ and ‘Nasiri’ the female sterility was observed as higher than that of other cultivars. Cultivar ‘Jahangiri’ did not suffer from female sterility.

To study the genetic relationships among Iranian onion landraces and to compare them with those in some foreign cultivars, fifteen microsatellite (SSR) primer pairs were employed. Based upon the results of the obtained band pattern, 12 pairs of SSR primers in 18 onion landraces and five foreign cultivars form a polymorphic and scorable pattern. There were two to six alleles with an average of 3.3 to every gene location. The polymorphic information content was assessed from 0.2 to 0.76 with a mean of 0.52, which was a proof of high heterozygosity in the masses of landraces. Mean genetic diversity within the landraces and within the foreign cultivars varied from 0.12 to 0.28. Analysis of molecular variance based upon square Euclidean distances indicated significant diversity between and within onion landraces and foreign cultivars. However, the amount of variance between varieties (0.42) was less than that between foreign cultivars (0.58). Grouping through Nei similarity coefficient and UPGMA algorithm, separated the onion landraces and foreign cultivars into six groups and an independent genotype. Although grouping on the basis of molecular data was rather compatible with some of the morphological traits, but it did not, as a whole, match the geographical grouping.

Water and nutrient absorption by plants is one of the most conspicuous factors which seriously affect plant productivity. Improving physical properties of soilless media and their water retaining capacity can improve plant's nutrient absorption, growth and subsequent yield. In this study, we tried to improve plant nutrient absorption through incorporation of hydrogel into growth media and practice of grafting to evaluate their effects on growth parameters, yield and fruit quality in greenhouse cucumber. Greenhouse cucumber cv. Kaspian (in two states of either grafted onto Cucurbita pepo L. rootstock or non-grafted) were planted in perlite either with or without hydrogel (Super ab-A200, incorporation rate 1.5%w/w) addition. Fertigation was applied either at full (equal to total water requirement of plants) or reduced (70% of water requirement) levels. Results indicated that fertigation level just affected leaching fraction, causing it to increase in complete fertigation treatment. Adding hydrogel into media led to a decrease in leaching fraction and increased yield, root and leaf dry weight, relative growth rate (RGR), net assimilation rate (NAR) as well as biomass with no effect on fruit quality factors. Grafted plants bore higher RGRs and consequently higher yields and higher levels of biomass, in media with no hydrogel application.

Drought tolerance of three own-rooted grape cultivars (Rashe, Ghezil Uzum and Red Sultanina) was evaluated at four different levels of soil moisture contents (40, 60, 80 and 100% field capacity through a factorial experiment based on a randomized complete block design with three replications for a duration of 3 months. Results revealed that, grape cultivars, levels of soil moisture and the interaction between them had significant effect on fruit's morphological and physiological parameters. However, leaf temperature did not differ significantly among cultivars. With decrease in soil moisture from field copacity (F.C.), shoot length, number of leaves per plant, leaf area, fresh weight of leaf, dry weight of shoot and root relative water content (RWC) as well as chlorophyll index were significantly decreased, while leaf temperature, proline content and soluble sugars were increased. All the evaluated parameters, except leaf temperature and soluble sugars, were higher in “Rashe” than in other cultivars, but the level of soluble sugars was higher in “Ghezil Uzum” compared with others. The highest leaf chlorophyll index were observed for 100, 80 and 60% of F.C. in “Rashe” while the lowest chlorophyll indexes being observed in “Ghezil Uzum” and “Red Sultaninia” for the treatment of 40% of F.C. In the 40% of F.C. treatment, leaf temperature of “Red Sultaninia”, proline content of “Rashe” and soluble sugars in “Ghezil Uzum” were higher in comparison with those of the others. Based on the obtained results, “Rashe” and “Red Sultaninia” cultivars, were respectively found as the most, and the least drought tolerant cultivars.

Phosphorus induces flowering and helps seed formation, but there is a big gap between phosphorus supply from natural sources and agriculture and industry demand. In order to investigate phosphorus feeding over long time from Iran region's apatites on Rose plants characteristics, var. Black magic in zeoponic culture, an experiment was conducted as factorial on the basis of completely randomized design with three replications, that evaluated the effect of 8 types of media with different percentage of apatite, zeolite, perlit and soil, with 5 types of nutrient solution (3 types of Coïc et al. solution and 2 types of solution like a proper soil solution) with different concentrations. The media were provided and used for a similar study one year ago. In this study phosphorus leaf content and flowering indices like pedicel diameter, bud diameter, bud height and bud number were measured. The results showed that the most of the media and all nutrient solutions had a significant effect on these indices. In all of measured factors, Coïc et al. solution (as control) was the most suitable solution that didn’t have significant difference with half strength of Coïc et al. solution. Medium including 1% Delir region apatite with the leaf phosphorus mean of 0.6% (in dry matter) created better results than other media; however, in many measured indices, there was no significant difference with other media except medium including Moondon region apatite and without soil with the leaf phosphorus mean of 0.48% (in dry matter).

Combining ability and heterosis were studied in a 6×6 partial diallel cross during 2007-2009 to see the nature of gene action in cucumber (Cucumis sativus L.). Analysis of variance revealed high significant differences among all the F1 hybrid means and among their respective six parental values for all the traits examined. The mean squares attributed to General Combining Ability (GCA) and Specific Combining Ability (SCA) were also highly significant. SCA genetic variances were greater than those of GCA and more important for the traits of Marketable Yield as well as Simple Weight Index, showing the dominance of non-additive gene action. Early yield and nonmarketable yield were controlled by additive and non-additive type of gene action due to high GCA variances. Line 504 with its bearing of high general and specific combining ability is finally found desirable regarding cucumber hybrid seed production and therefore is recommended.

Alstroemeria (Alstroemeriaceae family) is an ornamental monocot mainly produced for its cut flowers. Embryogenic calluses have been employed for gene transformation in Alstroemeria. This research work was undertaken to study the embryogenic callus induction in Alstroemeria cv. Fuego. The vegetative explants (node, internode, leaf) along with various concentrations of auxins (picloram, NAA, IAA, 2, 4-D) either with or without BAP were taken into experimentation. The nodal explants provided the highest embryogenic calluses. The internodal explants resulted in a lower embryogenic callus production than the nodal ones. The leaf explants did not prove any suitable for callus induction. The highest induction rate of embryogenic calluses was obtained for ½ MS medium supplemented with 2 mg/l of NAA. As for regeneration, callus was transferred to regeneration medium supplemented with 2 mg/l of BAP.

To study the genetic variations in pistachio cultivars, 42 female pistachio cultivars from Station No.2 of Rafsanjan, 25 cultivars from Pistachio Research Station of Kerman, 40 cultivars from Station No. 1 of Naseriyyeh region, 3 cultivars from Damghan region, as well as 5 ones from Khorasan region were taken for experimentation. To carry out cluster analysis based on morphological traits, the pertaining characteristics were assessed. Following measurement and collection of data, cluster analysis was done through use of SPSS statistical software based on the obtained characteristics, and then the related tree chart was obtained. Results placed Rafsanjan cultivars into 10 groups, Naseriyyeh cultivars into 12 groups, and Kerman cultivars into 6 separated groups. The cluster analysis of all the cultivars within all the regions delineated the classification of the cultivars as regionally, in which, cultivars of various regions got palced in separate groupings, illustrating the effects of environment on morphological characteristics. Similar cultivars in different regions revealed different morphological characteristics, causing cultivars in various regions of close genetic similarities not to be palced in one group based on morphological characteristics. So, in order to study the genetic variation in cultivars prevalent in different regions, in addition of morphological characteristics, molecular markers such as DNA and proteins must also be used. Cultivars of Damghan and Khorasan regions were palced in one group, cultivar Shahpasand of Damghan plus cultivar white Badami (almond-like) of Khorasan, as well as cultivar Abbas-ali of Damghan and cultivar Barg Siyah (Black Leaf) of Khorasan were proved to have very close genetic similarities based on respective Cosine Similarity Coefficients of 0.893 and 0.908.

An analysis of the stages of crop growth presents an important step in the improvement of production management. Through growth analysis, planning for planting systems, fertilization, pruning operations, harvest time as well as obtaining economical yield can be more accessible. Therefore, a development of mathematical models simulating plant growth would be helpful in improving crop management, particularly fruit growth. In the present study, in addition to linear model, six nonlinear growth models as well as a linearized biexponential (LinBiExp) model were employed to make modelings of the inherent growth pattern of ‘Red Spur’ apple fruit based on the measured parameters of fruit length, diameter and volume. The parameters were estimated using the Marquardt iterative method of nonlinear regression. A selection of the most appropriate model calls for the use of such quantitative model selection criteria, as r2, partial F-test, the Akaike information criterion as well as the Schwarz Bayesian information criterion. Throughout the study, it was found that the LinBiExp model was a more suitable one than the other nonlinear growth models as regards fitting the apple growth data attained from the assessed dimensional traits. Moreover, a study of the effect of crop yield on the fruit growth pattern revealed that the final fruit size was in direct relationship with the growth rate in the linear portion. A high crop yield trial led to a decrease in the linear growth rate portion, resulting in smaller size fruits at harvest.

Despite extensive use and cultivation of "Tareh Irani" the native vegetable of Iran, there has been few research works carried out on it, specially regarding its drought tolerance. This research was conducted to study the effects of five drought levels (30, 50, 80, 200 and 500 kPa) on yield and some morphological as well as physiological characteristics of two Tareh Irani populations (Hamedani and Shadegani), employing a factorial experiment of completely randomized design. The drought stresses were applied following the 2nd cut of plants. The results revealed that drought stress exerted significant effects on all the characteristics but effects of population cultivars and their and its interaction effects with drought stress were not significant. By increase in the level of drought stress, yield, leaf number, leaf area, dry matter percentage, chlorophyll contents of leaves, relative water content and water potential of leaves decreased but the ratio of root fresh weight to leaf fresh weight and as well the number of stomata increased. The results were similar for different cuts. In comparison with control (30 kPa) the yield in 50, 80, 200 and 500 kPa drought treatments decreased by 14, 46, 75 and 82 percent, respectively. The results were observed to be similar for other quantitative traits. Finally, taking into account the potential of Tareh Irani for keeping its relative water content and as well its water potential of leaves in favorable levels in face of high levels of drought stress, this plant can be considered as a tolerant plant to drought stress, but on the other hand a high decrease in yield and in some other quantitative traits of this vegetable in moderate to high levels of drought stress, can lead to its being classified as a sensitive crop to drought stress.