Introduction
Vegetative propagation of plants is useful for maintaining desired genetic constitution, multiplication of plants and for developing desirable clones. Auxins are being increasingly used in horticulture and forestry to promote rooting of comparatively difficult-to-root cuttings. However, in many cases even auxins fail to root cuttings („Hartmann and Kester,1983‰); („Nanda and Kochhar, 1985‰). Growth regulating substances like IAA, IBA, and NAA are the tools which have been used successfully in propagation of many valuable plant material („Kumar and Arumugam, 1980‰)). Survey of literature reveals that auxins induced the formation of adventitious roots on the stem cuttings of a number of plant species.Vegetative propagation is generally considered as an important part of tree important programme in regeneration („Nanda, 1970‰). It is very important to understand the factor which affect the rooting of cuttings in general, and efficacy of auxin in promoting rooting in particular. One of the most important factors affecting rooting potential of stem cuttings is the season of taking and planting cuttings („Nanda,1975‰). These changes in rooting behaviour of cuttings are caused due to seasonal changes in the biochemical status, especially with respect to carbohydrate reserves and endogenous contents of regulatory substances („Nanda and Kochhar,1985‰).
[i+]]Jatropha curcas is potentially useful and versatile tree/shrub of family Euphorbiaceae. Cultivated mainly as an oil seed crop.Jatropha curcas can be propagated In three ways, through seed, transplanting seedlings and through stem cutting. The growth and yield of the plant is comparatively low through stem cutting as compared to sowing through seed and seedling transplanting. The oil extracted from the seeds of Jatropha curcas has a very high saponification value and is extensively used in India and other countries for soap making. At present Jatropha oil is imported to meet the demand of cosmetic industry. This oil is also used as a lubricant, hydraulic oil and for making candles as from Castor oil. Jatropha oil is environmentally safe, renewable source of non-conventional energy and a promising substitute for diesel, kerosene and other fuel oils. [i+]]Jatropha curcas plants have a productive life of nearly 40 to 50 yearswithout necessary replanting or retending unlike fuel wood crops. So keeping inview the important aspect of this plant, the present investigation was, therefore undertaken worth a view of studying the relationship between the biochemical status of branches, as affected by the changes of season and the effectiveness of auxin in causing promotion of rooting in the stem cutting of [i+]]Jatropha curcas.
[[Material and Method]]
A pilot survey of population of [i+]]Jatropha curcas in sub-tropical region of Himachal Pradesh was undertaken to identify the site where species occur in natural form. The sites selected for study are confined in Sirmour, Bilaspur, Hamirpur, Mandi and Solan districts of Himachal Pradesh. The altitude of the entire range varies from 400-1100 m above mean sea level. The stem cuttings of [i+]]Jatropha curcas were collected from the naturally occurring trees of approximately same height from selected sites, At least three cuttings were obtained from a single stem based on portion of stem cutting i.e., terminal(I1), middle (I2), basal (I3). The top portion of each cutting was given an oblique cut and the base with horizontal cut. The fresh cuttings were treated with IBA of different concentration (in solution medium). Viz. control (water), 0.25% IBA, 0.50 % IBA, 0.75% IBA and 1% IBA. Whereas, cuttings under control were planted as such without any treatment. The cuttings were planted in the open nursery conditions in the month of July 2004 during rainy season and in the month of Feb 2005 during winter season.
Preparation of hormonal formulation:-
The desired amount of IBA was dissolved in small quantity (10-15 ml) of absolute alcohol in a 50 ml beaker, thoroughly mixed then add desired quantity of distilled water with continuous stirring to form crystal clear solution and to avoid buffering.
Method of hormonal application:-
The bottom portion of each cutting was dipped in hormonal formulation followed by quick dip of 5 seconds.
Planting condition of cutting material:-
The rooting studies on cuttings was undertaken in open nursery conditions for rainy and winter season.
Planting techniqe:-
The cuttings were planted in nursery beds of (2x1) m dimensions at a spacing of 15 x 15 cm with the help of wooden stick. The cuttings were then inserted 4-5 cm deep in nursery beds. Watering of the planted cuttings was done thrice a week at initial stage.
Results
Callus formation:-
Both hormonal treatments and cutting portion had non-significant effect on callus formation (Table 1). During rainy season maximum callus formation was recorded in T3 (2.67) and I1 (2.80) and minimum was recorded in T1 (0.89) and I2 (1.07). However all the treatments are at par with each other. Cutting portion I2 and I3 behaved statistically alike but differ from I1. Among the treatment combinations, maximum callus was recorded in T3I1 (4.67) and minimum in T1I2 and T4I3 (0.00) whereas all the combinations are at par with each other. During the winter season maximum callus formation was recorded in T1 (2.33) and I1 (2.80) and minimum in T5 (1.44) and I2 (1.07) whereas all the treatments are non-significant to each other. Cutting portion I1, I3 are statistically at par with each other but vary significantly from I2. Among the treatment combinations maximum callus formation was recorded in T1I1 (4.67) and minimum in T5I2 (0.67). However all the combinations had a non-significant effect on callus formation.
Sprouting per cent:-
Maximum sprouting was recorded in T3 (10.00) and I1 (11.33) during rainy season, whereas minimum sprouting was recorded in T1 (1.11) and I3 (2.66) (Table 2). Treatments T2, T3, T4, T5 are statistically alike but significantly differ from T1. Whereas I1 and I2 significantly differ from I3. Among the treatment combinations maximum sprouting was recorded in T2I1, T3I1, T4I1 (16.67) and minimum in T1I1, T1I2 (0.00), where as all the treatment combinations were found to be at par with each other. During winter season, maximum sprouting was recorded in T1 (38.89) and I1 (35.33) and minimum in T5 (22.22) and T2 (17.33). However, all the treatments were found to be statistically non-significant. I1, I3 differ significantly from I2 but are at par with each other. Among the treatment combination maximum sprouting was recorded in T1I1 (56.67) and minimum in T5I2 (10.00) whereas all the combinations are at par with each other.
Rooting per cent:-
During rainy season maximum rooting was recorded in T2 and T3 (10.00) and I1 (12.67) whereas minimum in T1 (1.11) and I2 (2.67) (Table 3). However T2, T3, T4, T5 vary significantly from T1. Cutting portion I1, I3 significantly differ from I2. Among the treatment combination maximum rooting was recorded in T2I1 (20.00) and minimum in T4 I2, T1I1, T1I2 (0.00). However all the treatment combinations are at par with each other. During winter season maximum rooting was recorded in T1 (15.56) and I3 (16.67) whereas minimum in T3 (5.56) and I2 (6.67). However all the treatments are at par with each other. Cutting portion I1, I2 are statistically alike but differ significantly from I3 (16.67). Among the treatment combinations maximum rooting was recorded in T1I3 (30.00) and minimum T3I2 (3.33). However all the combinations are at par with each other.
Number of roots/cutting:-
Maximum number of roots was recorded in T3 (2.56) and I1 (2.71) and minimum in T1 (0.33) and I2 (0.87) during rainy season (Table 4). However all the treatments are statistically alike. Cutting portion I2 and I3 are significantly differ from I1. Among the treatment combinations maximum number of roots were recorded in T3I1 (4.33) and minimum in T1I1, T1I2 and T4I2 (0.00). However all the treatment combinations are non-significant to each other. During winter season maximum number of roots were recorded in T1 (3.53) and I3 (5.13) and minimum in T4 (2.16) and I2 (1.67). However all the treatments are at par with each other. Cutting portion I1 and I2 significantly vary from I3. Among the treatment combinations maximum number of roots were recorded in T1I3 (6.77) and minimum in T3I2 (0.33). Whereas all the treatment combinations are at par with each other.
Root length (cm):-
Both hormonal application and cutting portion had non significant effect on root length. During rainy season maximum root length was recorded in T3 (1.21) and I1 (1.47) and minimum in T2 (0.77) and I3 (0.31) (Table 5). However all the treatments and cutting portions are at par with each other. Among the treatment combinations maximum root length was recorded in T4I3 (2.50) and minimum in T1I1, T1I2 and T4I2 (0.00) whereas all the combinations are at par with each other. During winter season maximum root length was recorded in T1 (1.87) and I3 (2.56) with minimum in T3 (0.87) and I1 (0.60). However all the treatments are at par with each other. Cutting portion I1, I2 are alike but significantly differ from I3. Among the treatment combinations maximum root length was recorded in T3I2 (5.00) and minimum in T2I1 (0.13). Whereas all the treatment combinations are at par with each other.
Discussion
The results of present investigation indicate that treating of cuttings with IBA solutions of different concentrations showed no significant variation for different rooting characteristics except sprouting per cent and rooting per cent in rainy season. This marginal success may be attributed to IBA treatments as no success was registered in control treatment. Similar findings were reported by(„1969‰) in Helianthus tuberosus. In winter maximum rooting and sprouting was recorded in T1 (control). This clearly shows that IBA have no effect on rooting characteristic in winter season but register marginal success in rooting of Jatropha cuttings in rainy season when cuttings were treated with 0.5 per cent IBA concentration solution. Similar findings were reported by(„1983‰) showed that treatment ofJatropha cuttings with IBA hormone did not promote root formation. The rooting of cuttings is influenced more by rooting media, good aeration and drainage proved profitable. It is evident from the study that portion of cutting viz., Terminal, Middle and Basal registered significant variation for all the rooting characteristics in both rainy as well as winter season except for root length in rainy season. Callus formation and Sprouting per cent was recorded maximum in Terminal portion for both the season Variation in the performance of lower and upper portion of cuttings might be due to their marked differences in the level of biochemical composition. Whereas, maximum rooting per cent, number of roots/cutting and root length was recorded in Terminal cutting during rainy season and in basal cutting portion only during winter season.(„1994‰) reported that Acer oblongum and Quercus leucotricophora cuttings collected from lower portion of the shoot in the shoot in spring and from upper portion of the shoot in rainy season gave better performance. Time of the year or season when cuttings are taken and planted is important for their rooting. Magnitude of rooting even in species that root throughout the year varies considerably with the season(„1968‰) („1982‰) („1985‰) . In case of [i+]]Jatropha curcas cuttings, collected and planted during February-March performed better in respect of sprouting, rooting, root length, number of roots except callusing, as compared to the June-July collections.(„1984‰) also reported higher rooting from March than November collections in Sitka spruce. The failure of cuttings to produce a more elaborate root system in Jatropha curcas during June-July may be attributed to lower rate of photosynthesis in cuttings during this period as quoted by(„1973‰) or lower enzymes activity („1970‰)(„1974‰) and above all increased inhibitor to promoter ratio („1985‰).Although the cuttings of Jatropha curcas performed well in both the seasons but in general winter season resulted into better success in respect of all the rooting characteristics.
References
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