Shahin Jahangirzadeh khiavi; Behrooz Golein
Abstract
Introduction: Citrus fruits are the most common semi-tropical crops in the world. Acid lime (Citrus aurantifolia Swingle) is an important commercial fruit crop, cultivated in the south of Iran. High variation of acid lime fruits is observed in the south of Iran due to crossing within the other citrus ...
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Introduction: Citrus fruits are the most common semi-tropical crops in the world. Acid lime (Citrus aurantifolia Swingle) is an important commercial fruit crop, cultivated in the south of Iran. High variation of acid lime fruits is observed in the south of Iran due to crossing within the other citrus species and frequent bud mutation. Recently, Witch’s Broom Disease of Lime (WBDL) become a major limiting factor for lime production in the South of Iran as well as the main threating factor for lime industry in Iran. Having knowledge about the genetic of this plant is helpful for designing citrus breeding program. Therefore, in this research morphological traits were used to understand the genetic relationships and diversity of this gene pool.
Materials and Methods: Thirty citrus samples, including 23 undefined local and native genotypes and seven known cultivars were collected from four regions in Iran (Darab (54.53E, 28.75N), Manojan (57.49E, 27.40N), Minab (57.07E, 27.14N) and Ramsar (50.64E, 36.92N)). Forty-one (32 qualitative and nine quantitative) traits were investigated using leaves, fruits and seeds. The selection of morphological traits were made based on IPGRI descriptors. The similarity was calculated by simple matching coefficient and dendrogram was designed based on UPGMA algorithms. Principal components analysis was performed.
Results and Discussion: Genetic diversity of 23 lime genotypes and seven commercial cultivars were investigated by using 41 morphological characters. Based on gained data similarity matrix (Jaccard, Dice and Simple maching) were calculated and dendrogram based on UPGMA algorithms were designed. To finding better similarity coefficient, cophenetic test was done, it showed that if used SM coefficient 79 percent of data of similarity matrix was shown in designed cluster based on UPGMA algorithm. According to results, range of similarity was between 0.141 until 0.683. Maximum similarity was observed between two lime cultivars (Persian lime and Mexican lime). Average of similarity was calculated 0.39. In cluster analyses of studied samples at 32 level of similarity samples were divided into four main groups. First group has only one member and it was pomelo, as it is one of the ancestors of citrus fruits, this is quite acceptable. The notable point for second main group that it included all examined samples of Minab. As in this region most of cultivated citrus are lime, there is little gene mixing with other citrus. The third group consist of two cultivars sweet orange and Citon that intended in present investigation. Fourth group which was the biggest created groups that included more than half the samples (56%) was more complex because it consists of samples of limes and lemons that intended in investigation as control and samples of Darab and Manojan. This main group at level of 0.38 divided into three sub-groups, at first, Lisbon lemon was separated from other samples and next Manojan samples created their special sub-group and finally third sub-group which consist of 11 members (samples of Darab, MA6 from Manojan and three commercial cultivars, Persian lime, Mexican lime and Rough lemon). Principle Component Analysis (PCA) showed the first five principal components, which contributed 59.01% of the total variability of investigated samples. Maximum variability was contributed by the first component (22.77%) followed by the second component (12.54%), and the third component (9.85%). A two‐dimensional plot (2D plot) generated from PCA showed three groups. This grouping was roughly in line with the distribution of the samples in the resulting cluster analysis based on SM coefficient and UPGMA algorithm. Principle Component Analysis using 41 descriptors showed that 26 of 41 descriptors were informative and contributes significantly to the variation present in the germplasm.
Conclusion: This study described and estimated the extent of phenotypic variation present among the samples of limes from Iran germplasm. Morphological analyses among 23 genotypes and seven commercial cultivars from four regions of Iran were successfully used to calculate genetic diversity and genetic relationships. According to our results, it was confirmed that morphological analyses in limes and other Citrus species were exploit to determine genetic diversity and relationship, successfully. Characterization by using morphological descriptors based on 41 characters, revealed significant diversity in traits of leaf, fruit and seed. This investigation display the use of morphological characters to study genetic diversity of Iranian lime genotypes from four different regions that their relationships were somewhat clarified. The results of this study also opened a door to tackle the long standing problem of citrus classification and identification in Iran. But, we suggest that this type of study needs to be continued due to Iran has a very large and numerous citrus germplasm. In south and central regions of Iran, it is being propagated by seed which gives researchers a chance to find new genotypes that need to be classified, investigated and introduced as a new cultivar.
Behrooz Golein; Vali Rabiei; Faezeh Mirabbasi; Reza Fifaei; Mohammad Fazel Halaji Sani
Abstract
Introduction: Citrus (L.) is a large genus that covers several major cultivatedspecies, including Citrussinensis (sweet orange), C.reticulata (tangerine and mandarin), C. limon (lemon), C.grandis (pummelo), and C. paradisi (grapefruit).Citrus is one of the world’s important fruit crops and grown inmost ...
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Introduction: Citrus (L.) is a large genus that covers several major cultivatedspecies, including Citrussinensis (sweet orange), C.reticulata (tangerine and mandarin), C. limon (lemon), C.grandis (pummelo), and C. paradisi (grapefruit).Citrus is one of the world’s important fruit crops and grown inmost areas with suitable climates between latitude 35◦N–35◦S. InIran, citrus industry is of paramount importance. Citrus species have been classified as salt-sensitive crops, although their relative tolerance can be influenced by climate, fertilization, soil type, irrigation method and rootstock. Citrus rootstocks differ in their ability to exclude Cl−and/or Na+from the scion. Many authors have contrasted the relative abilities of rootstocks to restrict movement of salts to the scions. The rootstocks Cleopatra mandarin (C. reshni), Rangpur lime (C. limonia) and Severiniabuxifolia (Poir) Tenore were relatively effective in restricting Cl−transport to scions, whereas the rootstocks Swingle citrumelo and Carrizo citrange were found to be less restrictive. Although the mechanism by which some rootstocks reduce concentrations of ions in the scion is still unknown, it seems to depend on the vigor of the scion and on water requirements. There are a number of reports demonstrating that both scion and rootstock may influence Cl−accumulation in leaves. Several papers reported that accumulation of Na+ in shoots seemed to be more dependent on rootstock–scion combinations. Since, citrus species are different in salt tolerance and use of tolerant rootstocks can decrease salinity damages, sothis study was conducted to identify tolerant genotypes among unknown types from the Kotra Citrus Research Station, Citrus and Sub-Tropical Fruits Research Center (Ramsar).
Materials and Methods: The experiment was –arrangedin afactorial, based on completely randomized design in three replications with two plantsin each experimental unit in Iran Citrus Research Institute.Treatment included 10 citrus natural genotypes along with two varieties of Cleopatra mandarin (tolerant plant) and Swinglecitrumelo (sensitive plant) with six-month old and four salinity levels of sodium chloride: 0(control), 2, 4 and 6 dsm-1, for 16 weeks in the greenhouse condition. Effect of salinity on fresh and dry weight of shoot and root, relative water content (using upper leaves), stomatal density (with counting of stomata using microscope), concentration ofCl (with titration method of silver nitrate) and Na (by flame photometry) in roots and leaves, content of total chlorophyll (using acetone 80%), proline (spectrophotometry at wavelength of 520 nm), lipid peroxidation (spectrophotometry at wavelength of 532 nm) and activity of peroxidase enzyme (spectrophotometry at wavelength of 470 nm)were investigated. Data analysis was done by SAS 9.1 software.
Results and Discussion: The results indicated that, the interaction of genotypes and salinity levels hadnot significant difference in relative water content, stomatal density and Na+concentration - in roots but, other traits except total chlorophyll content which was significant at 5% level, were significant at 1% level. Shoot fresh and dry weight of genotypes No. 4 and 6 were significantly (P
