Seyed Javad Sanei; Seyed Esmael Razavi
Abstract
Verticillium dahliae Kleb. the causal agent of vascular wilt is an important pathogen of olive trees in growing areas of the world. Nine-month-old nursery olives including ‘Bladi’, ‘Conservalia’, ‘Kalamon’, ‘Koroneiki’, ‘Manzanilla’, ‘Mission’, ...
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Verticillium dahliae Kleb. the causal agent of vascular wilt is an important pathogen of olive trees in growing areas of the world. Nine-month-old nursery olives including ‘Bladi’, ‘Conservalia’, ‘Kalamon’, ‘Koroneiki’, ‘Manzanilla’, ‘Mission’, ‘Marry’, ‘Picual’, ‘Rowghani’, ‘Sevillana’ and ‘Zard’ cultivars were root-dip inoculated with a defoliating (VCG1) isolate of V. dahliae obtained from diseased olives. Resistance was evaluated by assessing symptom severity using 0-4 rating scale and estimating the area under disease progress curves. The percentage of plants killed and final mean severity of symptoms were used as additional parameters for classifying the cultivars. Most of the tested cultivars were susceptible or highly susceptible to Verticillium wilt. However, two genotypes ‘Kalamon’ and ‘Koroneiki’ exhibited high resistance or resistance to this disease. Vegetative growth was reduced in inoculated plants due to infections caused by V. dahliae, although the reduction was remarkably higher in susceptible than in resistantcultivars. Correlation coefficient analyses revealed a negative relation between disease severity and vegetative growth. Dendrogram of olive cultivars based on all parameters represented two main clusters, major and minor. Minor cluster comprised only ‘Kalamon’ and ‘Koroneiki’ cultivars as resistant to V. dahliae. The major cluster could be divided into two groups, exhibiting extremely susceptible or susceptible reaction to V. dahliae.
Abdolhossein Aboutalebi Jahromi; Mehdi Hosseini Farahi
Abstract
Marigold has special importance and application in landscape designing. Nowadays, various species and cultivars of this plant are grown in many climates, where different environmental stresses such as freezing, salinity and drought can lead to vegetative disorders. This study was carried out to investigate ...
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Marigold has special importance and application in landscape designing. Nowadays, various species and cultivars of this plant are grown in many climates, where different environmental stresses such as freezing, salinity and drought can lead to vegetative disorders. This study was carried out to investigate the interactions between salinity and ammonium nitrate on seed germination, vegetative growth and sodium and potassium concentrations in French marigold flowers (Tegeta patula). The experiment was conducted as a factorial arrangement based on a completely randomized design with two factors: salinity (0, 2, 4, 6 and 8 mmos cm-1) and ammonium nitrate (0, 15 and 30 g l-1) with four replications. Based on the obtained results, different salinity concentrations were negatively influenced all studied parameters except germination rate. The application of ammonium nitrate recovered the studied parameters to the same level as the control plants. Plant height was decreased by increasing salinity concentrations. The tallest plant was observed in the control treatments. Salinity levels negatively influenced shoot fresh weight. Different levels of ammonium nitrate had significant effects on root dry weight and potassium and sodium contents. Ammonium nitrate led to reductions in root dry weight and potassium content, and an enhancement in sodium content in the shoot. Sodium and potassium levels were increased and root dry weight was decreased by increasing salinity. Enhancement of potassium ions in the marigold following salinity stress can improve its tolerance to salinity stress.
