IRANIAN JOURNAL OF HORTICULTURAL SCIENCE AND TECHNOLOGY
Year:2000 | Volume:1 | Issue:3-4|Papers Count:8

Auxins have been used by many propagators to increase the rooting in carnation cuttings. However, so far the effects of auxins on flowering of treated cuttings are not reported. This research was conducted in a commercial carnation greenhouse in Shahriar located in Tehran province from 1997 to 1998. The cuttings for this research were prepared from two cultivars of carnations, namely 'Giamaica' a standard carnation and 'Boriel' a miniature carnation. After selection of suitable mother plants, 8-10 cm lateral shoots formed at nodes were cut for preparing cuttings. In this research, two auxins, indolebutyric acid (IBA) at concentrations of 0, 50, 100, and 200 mg 1-1 and naphthaleneacetic acid (NAA) at concentrations of 0, 25, 50 and 100 mg 1-1and also the combinations of all concentrations of these two auxins were used. The cuttings were treated with auxin solutions for 10 min and immediately transferred to rooting medium. The rooting medium consisted of a mixture of equal proportion of sand and the ash of rice waste. This mixture is extensively used in the commercial greenhouses for carnation production. Treatment was evaluated in a completely randomized design with a factorial arrangement with three replications. Means were compared using Duncan's new multiple range test (DNMRT). Each replication consisted of 4 cuttings of which 2 cuttings were used for rooting and 2 cuttings for flowering data. The results showed that the used rooting medium was very suitable for rooting of the carnation cuttings. The different levels of two auxins and their combinations had no significant effect on rooting percentage at 5% level of probability when compared to control. While the number of roots were severely affected by auxin treatments. The highest number of roots was obtained at 50 mg 1-1 NAA and 100 mg 1-1 IBA (21.77 and 22.23 roots per plant, respectively). The best effect of different levels of auxins on root length was obtained at 100 mg 1-1 NAA (7.49 cm) and 100 mg 1-1 IBA (7.28 cm). Application of NAA and IBA increased dry and fresh weight of roots. The highest fresh weight was obtained at 50 mg 1-1 NAA (0.189 g) and 200 mg 1-1 IBA (0.184 g) and the differences were significant at 5% level of probability when compared to control. The highest root dry weights were obtained at 50 mg 1-1 NAA (0.028 g) and 200 mg 1-1 IBA (0.028 g). Treating carnation cuttings with IBA and NAA had a considerable effect on days to flowering, flower number, plant height and cut flower weight. IBA at 200 mg 1-1 decreased the days to flowering to 195.7 days compared to control which were 208.3 days and also was significant at 5% level of probability. Auxin treatments also affected flower number and the highest number of flower (17.3) was obtained at 200 mg 1-1 which was significantly different from control. Furthermore, the highest plant height (74.90 cm) was observed at 200 mg1-1 IBA which was significant compared to control at 5% level of probability. The highest flower weight was obtained at 100 mg 1-1 NAA and 200 mg 1-1IBA (34.98 and 36.79 g, respectively) and significantly differed at 5% level of probability compared to control. However, the effect of cultivars on some characters such as rooting percent, rooting length, dry and fresh weights of roots were not significant, but some other characters such as root number, days to flowering, flower number, plant height, flower diameter and the weight of cut flowers were affected by cultivar.

In order to delay the time of flowering of apricot, the trees of 'Royal' and 'Ordubad' cultivars were sprayed with single application of 0 , 5, 10 and 15% (v/v) degummed soybean oil in 1996 and 1997. Phenological development of flower buds was rated periodically from the time of treatment until the first bloom. Application of the soybean oil was effective and flower bud development was delayed by treatments. The trees treated with 15% degummed soybean oil bloomed 6 days later than untreated trees. The tolerance of flower buds in cold temperature was significantly increased in comparison with control (5% damage with 15% application with regard to 25% for untreated). Degummed soybean oil treatment significantly increased internal CO2. Application of the soybean oil caused bud damage and reduced flower bud density, but did not affect final fruit set and yield.

To evaluate the effects of plant growth regulators on thinning and quality of apple fruits, 6-benzyladenine (BA), naphtaleneacetic acid (NAA), carbaryl (CB), promalin (GA4+7 + BA) and their combinations were applied to apple cultivars 'Red Delicious' and 'Golden Delicious' in 1994 and 1995. In the first experiment, BA (50, 100 and 150 mg 1-1), NAA (10 and 20 mg 1-1), CB (600 and 1200 mg 1-1) and their combinations were applied to the branches of 'Golden Delicious' 2 weeks after full bloom. In the second experiment, BA (50, 100 and 150 mg 1-1) and promalin (50, 100 and 150 mg 1-1) were applied at full bloom to the branches of 'Red Delicious'. NAA, CB and their combinations and also combination of BA with NAA significantly induced fruit thinning and increased fruit weight of 'Golden Delicious' apple. Promalin at 100 and150 mg 1-1significantly increased L/D ratio of 'Red Delicious' apple. It is recommended to apply NAA, CB and/or their combinations at 2 weeks after full bloom to thin the fruits and to improve fruit quality of 'Golden Delicious' apple. Application of promalin at full bloom improved fruit shape by incresing the L/D ratio and consequently increased marketability of 'Red Delicious' apple.

Rooting is the main limiting factor in the micropropagation of Persian walnut (Juglans regia L.) due to the poor rooting capacity of this species. Two experiments were conducted to identify a suitable procedure for rooting of walnut microshoots. Rooting was performed in two successive phases: A) root induction and B), root development. In the first experiment, roots were induced in five different compositions of the basal nutrient media in darkness. After three weeks, for root development, the basal ends of shoots were dipped in talcum powder containing 2% IBA and were transferred to moisted Jiffy pots. Maximum rooting (42.5%) was obtaind by microshoots cultured on DKW medium (1/2-strength macronutrients) with full calcium nitrate which was signuficantly greater than other treatments. In another experiment, for root induction shoots were cultured on DKW medium (1/2-strength macronutrients) containing 0.2 mg 1-1 NAA and 3.0 g mg 1-1 activated charcoal for three weeks under lighted conditions. Then, the basal ends of shoots were dipped in 6 different rooting powders or auxin solutions containing different concentrations of IBA and were transferred to Jiffy pots. Maximum rooting (29.17%) was obtained by basal dip immersion of shoots in a commercial rooting powder (Seradix 3), containing 0.8% IBA. The use of Jiffy pots allowed rapid development of the root system and improvement in the quality of plantlets (higher number of roots, presence of secondary roots) and root development was synchronized with shoot elongation and development of new leaves. On transferring the plantlets to the greenhouse, their growth continued and more than 90% of plantlets survived.

Freezing tolerance in five apricot cultivars namely 'Shahroudi', 'Jahangiri', 'Nasiri', 'Nouri' and 'No. 35, was studied at the Horticultural Research Station of the Department of Horticulture, College of Agriculture, Karaj, I.R. Iran. In 1996, the effects of water stress treatments on seasonal variation of leaf soluble sugars and proline were studied. In 1997, flower blooming percentages, electrical conductivity of flowering bud extracts and ion leakages and percentages of flower damages were measured under water stress and control treatments. Results showed that soluble sugars accumulated in leaves during autumn months. The electrical conductivity and ions leakage (K+, Ca++) were decreased by water stress condition as compared with the control. Under water stress condition, significant positive correlation was found between spring flower damage percentage and electrical conductivity. In 1997, the highest percentage of spring damage was found in cultivar 'No. 35' and the least damage was noted in the case of 'Shahroudi'. The increase of EC of the flower bud extracts of cultivar 'No. 35' appeared to be related to the cold damages. Seasonal changes of the soluble sugars of apricot leaves were discussed, considering the sink strength and its relation to flower cold damages.

A series of experiments were conducted to examine the effects of chemical treatments on weight loss, decay and other fruit characteristics of two cultivars of mandarin ('Clemantin' and 'Kinnow') during 1998 and 1999 both in cold (6±1°C) and ambient storage. Wax emulsion (50% and 75%), imazalil (750' and 1000 mg 1-1) 2, 4-D isopropylester (1000 and 1500 mg 1-1) and their combinations were applied to the fruits of 'Clemantin' and 'Kinnow'. Treated fruits were stored at cold and ambient storage for 3 and 5 months, respectively. Weight loss of fruits in ambient storage was higher than in cold storage. Treatments with wax-emulsion containing imazalil or 2,4-D were effective in reduction of weight loss in both storage conditions. The highest and the lowest weight loss were found in non-treated and fruits treated with 75% wax, respectively, during 3 and 5 months storage. Imazalil was more effective than 2,4-D in reduction of decay during storage. Wax treated fruits had lower soluble solid content that non-treated fruits in ambient storage.

Saffron (Crocus sativus L.) is one of the oldest spice and medicinal plants. The stigma of saffron flower is not only used in food, confectionery and liquor industries but has also medicinal properties and is used as apetizer, digestive and sedative. Saffron is cultivated mainly in warm-arid and salt desert regions of south of Khorasan province. Due to high economical efficiency of saffron, its cultivation is increasing in different parts of our country. Nowadays, saffron is mostly cultivated in the north of Khorasan province. Since the environmental factors have significant effect on the productivity (growth, development, yield and quantity and quality of active substance)of medicinal plants, the main aim of this investigation that took place in Ferdows (in the south of Khorasan) and Neishabor (in the north of Khorasan) was to find out the effects of climate on the productivity of saffron. The results show that climate significant affected the productivity of saffron. The quantity and quality of saffron (except aroma property) of Neishabor region was better than saffron produced in Ferdows region.