Ali Asadi Kangarshahi; Negin Akhlaghi Amiri
Abstract
In a two-year pot experiment, the response of Miyagawa satsuma mandarin on Swingle citrumelo rootstock was investigated in soils with different ranges of lime. Furthermore, in a field experiment, the plant growth trend, yield, and quality were studied in two regions (plain and piedmont) for 10 years. ...
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In a two-year pot experiment, the response of Miyagawa satsuma mandarin on Swingle citrumelo rootstock was investigated in soils with different ranges of lime. Furthermore, in a field experiment, the plant growth trend, yield, and quality were studied in two regions (plain and piedmont) for 10 years. In the pot experiment, the highest shoot dry weight was obtained from soils with 14% total lime and in soils with more total lime, shoot dry weight decreased sharply. The most chlorosis rate was obtained in soils with more than 30% lime. The highest total Fe in the roots and the least signs of leaf chlorosis was detected in the soils with less than 9% lime. The average Fe concentration in the roots was about 7.5 times more than that in the leaves, indicating accumulation and deposition of Fe in the roots. The amount of available Mn was excessive in most soils but leaf Mn in most cases was less than adequate. The Mn concentration in the roots was 3.2 times more than that in the leaves. The field experiment showed that tree volume in the plain was always higher than that in piedmont. The trees of the piedmont had alternate bearing cycles. The yield increased from 23 kg per tree at the beginning of the reproductive period to 80 kg in the final year of the experiment. The best harvest time in both regions was early October. Generally, use of this rootstock in soils with less than 9-14% total lime, is recommended.
Negin Akhlaghi Amiri; Ali Asadi Kangarshahi; Kazem Arzani; Mohsen Barzegar
Abstract
Summer fruit drop (June drop) is one of the main reasons for low yield in some citrus varieties in northern Iran. Recognition of physiological changes in fruit abscission zone (calyx) and application of suitable treatments would reduce or control abscission. Hence, the changes of auxin, cellulose, and ...
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Summer fruit drop (June drop) is one of the main reasons for low yield in some citrus varieties in northern Iran. Recognition of physiological changes in fruit abscission zone (calyx) and application of suitable treatments would reduce or control abscission. Hence, the changes of auxin, cellulose, and polygalacturonase in calyx of Thomson navel fruitlets were measured and their relations with abscission and mineral nutrition of fruitlets as well as the effect of different treatments on them at June drop were evaluated. A randomized complete block design (RCBD) experiment was performed with 8 treatments and 4 replicates. Treatments were as follows: 1. control; 2. urea (1%); 3. urea + 2,4-D (15 mg l-1); 4.urea + GA3 (15 mg l-1); 5.urea + sucrose (1%); 6.urea + ZnSO4 (0.5%); 7. urea + ZnSO4 + 2,4-D; and 8. urea + ZnSO4 + GA3. Results showed that abscission had a significant negative correlation with auxin and a significant positive correlation with cellulase and polygalacturonase of the calyx. The control group had the lowest auxin and the highest cellulase in calyx. Maximum effect (Approximately 24% reduction in abscission) was obtained after foliar application of urea + sucrose (treatments 5). The use of urea alone or in combination with 2, 4-D and GA3 had no effect on abscission; however, using it in combination with sucrose was the most efficient treatment in this experiment. Furthermore, the combination of urea and Zn provided an effective treatment. A majority of micronutrients (Mg, Fe, Mn, Zn, Cu and B) had a positive correlation with auxin and a negative correlation with enzymes. Therefore, nutritional management and providing an appropriate condition to maximize photosynthesis can balance physiological metabolism and reduce fruitlets abscission.
