نشریه نهال و بذر
سال سی و چهارم شماره 3 (پاییز 1397)

To investigate karyotipic variation in tea genotypes, karyotype of 16 tea genotypes were studied. Chromosomal parameters including total length of the chromosome, long arm, short arm, arm ratio and centromeric index were measured and analysed. Analysis of variance showed significant variation among genotypes in total length of chromosomes, length of long and short arms. The results of karyotypic formula showed that the chromosomes were metacentric and sub-metacentric. The satellites and nucleotide organizer regions were observed in genotypes 277 and 581. Except for the genotype 2021, which was triploid (2n = 3x = 45) and is reported for the first time, the remaining 15 genotypes were diploid (2n = 2x = 30). Based on karyotypic analysis and classification of karyotypes, genotypes 277 and 444 were classified 1B and 2B, and 14 genotypes were classified in classes 1A and 2A. Thus genotypes 277 and 444 were asymmetric. Principal component analysis based on karyotypic parameters showed that total length of chromosomes and length of long arm played the most important role in the first component. The first component explained 54.83% of total karyotypic variation. Cluster analysis also classified the genotypes into five groups.

This study was conducted to evaluate vegetative, reproductive and pomological characteristics of eight promising olive genotypes, originated from Tarom and Gorgan regions in Iran. Te experiment was carried out in randomized complete block design with three replications in 2013-2015 at Taram olive research station, Tarom, Zanjan, Iran. Results showed that tree height, trunk cross sectional area (TCSA) and canopy width were significantly different among olive genotypes. The number of inflorescence per branch, the number of flower per inflorescence, percentage of complete flowers, percentage of initial and final fruit set were also significantly different among genotypes. Mean fruit weight varied between 2.5 to 8 grams. T2 had the highest (6.9 tonha-1) fruit yield. All genotypes had greater than 40 percent oil content in dry matter. T7 with mean fruit yield of 5.8 tonha-1 and more than 50 percent oil content in dry matter was identified as a promising genotype for olive oil production. T2 was found a suitable genotype for dual purposes.

The consumption of rice containing minerals and phytochemicals reduces the risk of developing diseases. Understanding of diversity, genetic structure and quantity of phytochemicals in rice are necessary for developing breeding program to improve quality related traits. In this study, crosses were made between six genotypes; Sepidroud, Amol 2, Danesh, Abjibouji, Musa-Tarom and Sadri as male (line) with four genotypes; Gharib, Onda and Fajr and IR64724R as female (tester), in 2016. The progenies and their parents (34 genotypes) were evaluated in randomized complete block design with three replications in 2017 at the research farm of Sari Agricultural and Natural Resources University. Nutritional quality related traits inducling; antioxidant capacity, total phenol, carotenoids, soluble and insoluble carbohydrates, Fe, Zn and protein contents, and cooking quality related characteristics including; amylose, gelatinization temperature and gel consistency were measured. Evaluation of genetic variance components of the studied traits showed that the proportion of non-additive variance was more than additive variance. General combining ability of parents indicated that Fajr and Gharib were the best combiner for grain yield and nutritional characteristics, except soluble carbohydrates, and protein, and carotenoid and protein, respectively. Specific combining ability of crosses for increasing nutritional and cooking quality related charactetiristics and grain yield showed that Musa-Tarom × Gharib was the superior combination.

Eggplant (Solanumm melongena L.) is grown in most areas of Iran, but Verticillium wilt (Verticillium dahliae) causes complete wilting in different stages of growth, particularly during flowering and fruit production. There has been little success in controlling the disease by application of fungicides. Therefore, resistance of some eggplant genotypes was evaluated in this study. First the fungal isolates from different areas of Tehran province were collected and purified. Purification, pathogenicity test of isolates was conducted using root dip method, on Varamini susceptibe cultivar, in spore suspension. Microsclerotium production was carried out in a liquid medium. The microsclerotia obtained was mixed at 20, 25, 30, 35, 40, 45 and 50 microsclerotium per gram of soil, and seedlings were transplanted at two leaf stage. Disease severity index was calculated using 1-7 scoring scale. The results showed that 24 microsclerotia per gram of soil is required to cause 50% of the disease severity on susceptible eggplant genotype. The Resistance of 20 genotypes and varieties was assessed 35 days post inoculation using fungal spore suspension. Evaluation of eggplant genotypes showed that four genotypes including Hyb.Valentina14102, Hyb. Aro14701, Valentina -1 and Bj30 with disease severity index ranging from 31.5 to 49.7 percent identified as the tolerant group which showed 50 percent increase in fruit, root and shoot weight compared to susceptible genotypes.

Outbreak of witches broom disease of lime (WBDL) in major lime growing regions of Iran has necessitated research for tolerant lime species, Persian lime (Citrus latifolia Tanaka), to sustain lime production in southern part of Iran. In this context, a considerable number of unknoun lime genotypes have been cultivated by farmers and are known as Persian lime with no documented evidence of their origin, morphological characteristics and genetic background. To determine systematic relationship of lime genotypes known as Persian lime, we studied 18 lime genotypes collected from Fars, Hormozgan and Mazandaran provinces in Iran using flow cytometry technique and morphological characteristics in 2016 in Hormozegan Agricultural and Natural Resources Research and Education Center, Bandar Abbas, Iran. The results of flow cytometry revealed that 14 out of 18 lime genotypes were triploid and the remaing were diploid. DNA indexes for four diploid genotypes ranged from 0.896-1.000 and for triploid genotype varied from 1.313-1.563. Triploid genotypes had greater leaf dimensions and lower stomata and secretory sacs density. Results of this study showed that Kharkol, Cucumber-shaped and Egyption lime (which are known as Persian lime in south of Iran) genotypes, are diploid and can be susceptibile to witches broom disease of lime (WBDL) phytoplasma.

Autumn sugar beet planting demands less water than spring, however, one of the main requirements of autumn planting is bolting-resistant cultivars. Depending on the climatic conditions of the sugar beet growing region, different levels of bolting-resistance is required. The aim of the present study was to develop and evaluate sugar beet pollinators resistant to bolting based on half-sib genotypes selection. In October 2010, 250 half-sib families developed from two tetraploid populations 12460 and 12650 were grown and screened for bolting resistance in Oltan Agricultural Research Station in Moghan, Ardabil, Iran. Based on the results of bolting evaluation, four and one resistant populations were selected from 12460 and 12650 populations, respectively. In 2013, 120 families were developed from four populations of 12460 and 90 half-sib families were developed from single population of 12650. Selected families together with parental populations, four resistant and one susceptible controls were grown in autumn in 2013-14 and 2014-15 in randomized complete block design with three replications, in Moghan. Considerable variation was found among half-sib families for bolting resistance. Ninety-eight families in population 12460, and 47 families in populations 12650 showed significantly higher resistance than parental population illustrating the positive effect of selection for bolting resistance. Narrow-sense heritability for bolting resistance was estimated 85% and 66% for half-sib families developed from 12460 and 12650 populations, respectively.