Cent Rooting Research Articles

Optimization of Rooting Behaviour by the Application of IBA on the Cuttings of Queens Flower (Lagerstroemia speciosa)

Background: Queen’s flower (Lagerstroemia speciosa) is an important ornamental plant that is utilised in residential landscape and avenue plantation for both public and private purposes around the world. Seed dormancy problem in Lagerstroemia which negatively affects germination. To overcome the challenges associated with seed propagation, researchers have explored rooted Lagerstroemia speciosa cuttings as an alternative method. Methods: Three concentrations of IBA (Indole-3- butyric acid) @ 1000 ppm, 2000 ppm and 3000 ppm were used to root initiation of Lagerstroemia speciosa stem cuttings. There were four treatments: 1000 ppm, 2000 ppm, 3000 ppm and control. Result: The 2000 ppm IBA treatment performed the better response in comparision to other treatments and recorded, 79 per cent rooting, followed by the treatment 3000 ppm IBA, (76 per cent rooting) and in the control, (68 per cent). In 2000 ppm IBA, the percentage of rooting, the number of roots per cutting and the length of the longest roots all are at their peak as well as showed the superior growth performance. The growth parameters of IBA-@ 2000 ppm treated cuttings revealed that this is the optimum IBA concentration for Lagerstroemia speciosa propagation trough cuttings in a semi-arid climate.

Siddhast Technique: a new vegetative multiplication and water conservative technique for Jatropha curcas

Energy security is one of the prime concerns of any developing/developed nation and India ranks sixth in the world in terms of energy demand. The Indian economy is expected to grow at a rate of over 6 per cent per annum. The petroleum imports are expected to rise to 166 MT by 2019 and 622 MT by 2047, hence there is a growing need for energy security. Jatropha curcas has the potential to become a significant source of renewable energy if improved varieties are developed which can achieve its potential in terms of oil yield per hectare in marginal land. For vegetative multiplication, we have successfully carried out air layering in Jatropha curcas through siddhast technique, where a stem is induced to form roots using Rooter Strand while branch is still intact on the parent plant. Virtually no extra water is required to be given to the parent tree to produce a rooted plant. Here, we examined the competency of eight Rooter Strands vis-à-vis two conventional techniques of air layering i.e. tourniquet and gootee. Results showed that time for root initiation did not vary with treatments. In branches tied with Rooter Strand rooting started in minimum 3 weeks; the average root initiation period with Rooter strand was 4.56-6.66 weeks of installation. However, both conventional techniques T9 and T10 required 8.05 weeks and 6.40 weeks, respectively, to start root initiation. Significantly better rooting observed as compared with tourniquet technique and highest 100 per cent rooting was recorded in Rooter Strand-2, 31 and 41 along with control. Significant difference also observed among all the treatments representing Rooter Strand showed usually 83 per cent or higher for survival percent. This technique is very easy and does not require much skill. This technique has the advantages of air layering i.e. less need for physical inputs (water, electricity, infrastructure, etc). It reduces water consumption up to 90 per cent and electricity 100 per cent as compared to tissue culture. Thus, this technique is very conservative from cuttings and much faster than normal procedure of air layering for producing true-to-type plant material and can be adopted for multiplication of superior varieties of this species for their large-scale deployment for biodiesel production to ensure sustainable development with least water requirement.

Effect of plant growth promoting rhizobacteria (PGPR) and IBA treatments on rooting in cuttings of apple (Malus × domestica Borkh.) clonal rootstock Merton 793

The preliminary studies on the effect of different strains of plant growth promoting rhizobacteria (PGPR) alone and in combination with IBA at 1000 ppm on rooting in cuttings of apple clonal rootstock Merton 793 were carried out during 2012-13. The PGPR strains (RG (1)3 – Bacillus sp.), B6 – Bacillus licheniformis and R3 (3) – Sirretia sp. alone failed to induce rooting response in cuttings of apple clonal rootstock Merton 793. The results revealed that IBA 2500 ppm recorded the maximum rooting (65 %), number of primary roots (5.00), length (28.43 cm) and diameter (3.25 mm) of primary roots, fresh (3.67 g) and dry weight (2.59 g) of roots, length of main shoot (134.14cm), diameter of main shoot (8.18 mm), fresh (30.40 g) and dry weight (22.60 g) of shoots in cuttings of Merton 793. However, the PGPR strains RG (1)3 – Bacillus sp., B6 – Bacillus licheniformis and R3 (3) – Sirretia sp. in combination with IBA 1000 ppm showed improvement in rooting of cuttings to the extent of 10, 15 and 5 per cent rooting, respectively and growth of the rooted plants. IBA at 2500 ppm resulted better rooting and growth of rooted plants. Hence, this treatment is suggested for commercial propagation of apple clonal rootstock Merton 793 through cuttings.

Somatic Embryogenesis and Genetic Uniformity of Cassava Plants Regenerated from Secondary Somatic Cotyledons Preserved in Osmotic Agents

Somatic embryogenesis, plant regeneration and genetic stability of regenerants grown from cassava secondary somatic cotyledon preserved at 160C on medium containing mannitol or sorbitol alone and their combinations were investigated. Irrespective of osmotic agents in the medium, survival of cotyledon explant, frequency of somatic embryos, shoot induction, number of somatic embryo per explant, shoot elongation and rooting decreased as preservation period increased. The highest survival rate of cotyledon explants, frequency of somatic embryos, shoot induction and shoot elongation were observed on media containing 2% mannitol. However, the highest per cent rooting occurred on medium containing mannitol alone at 8 months after storage (MAS) and on media containing mannitol or sorbitol alone at 16 MAS. RAPD analysis suggested genetic uniformity among regenerants and their control plant. Osmotic preservation of secondary somatic embryos of cassava on 2% mannitol at 160C is the best slow?growth method.Plant Tissue Cult. & Biotech. 26(1): 47-54, 2016 (June)

Influence of different media on shoot regulation, shoot multiplication and callus induction in long pepper (Piper longum L.)

An experiment on tissue culture studies in long pepper ( Piper longum L.) was carried out in the year 1999-2001, to develop suitable protocol for plant multiplication technique at Green Earth Biotechnologies Ltd., Jigani Industrial Area, Bengaluru in collaboration with UAS, GKVK, Bengaluru. The concentration of 0.1 per cent mercuric chloride (HgCl 2 ) for 60 seconds to achieve disinfection of leaf segment explants was found effective, giving maximum survival (10.02 %) and minimum contamination (0.70 %). MS media containing BAP (1.5 mg/lit.) + 2,4-D (1.0 mg/lit.) from leaf explants gave higher (9.72 %) response for calli induction, 1.54 mg amount of callus with green colour and very good score of callus. BAP 3.0 mg/lit. was ideal for the better proliferation and regeneration of shoot (40 %).The Highest number of multiple shoots (2.00), Length of shoot (1.04 cm) and number of leaves per shoot (3.00), was produced using BAP (1.0 mg/lit.) + NAA(0.1 mg/lit.). Best results for shoot were observed with the MS media combination containing BAP at 1.5 mg/lit., Kinetin at 1.0 mg/lit. and IAA at 0.5 mg/lit., gave the maximum number of buds per calli (36.00) and number of shoots (5.20) and length of shoots (1.62 cm). The in vitro rooting was achieved with the application of NAA at 1.0 mg/l 70 per cent rooting, number of primary roots (2.40) length of primary root (2.00) and number of secondary roots (2.00).

Indirect organogenesis and assessment of somaclonal variation in plantlets of Vanilla planifolia Jacks

The low genetic variability of vanilla (Vanilla planifolia Jacks.) makes it susceptible to pests and diseases, which leads to a decrease in production. The genetic variability can be broadened by using in vitro plant tissue culture techniques. The use of indirect morphogenic routes allows increasing the percentage of somaclonal variation in regenerated plantlets. The objective of this research was to establish a protocol for indirect organogenesis in V. planifolia aimed at broadening the genetic base of the crop. A friable callus was induced from immature seeds grown in the dark, using MS medium supplemented with 2.27 μM thidiazuron (TDZ). Subsequently, 6.8 shoots per callus were regenerated in MS medium supplemented with 8.88 μM benzyladenine (BA). One hundred per cent rooting of regenerated shoots was achieved when MS medium was used with no plant growth regulators. Last, rooted plantlets were acclimatized in a greenhouse. A 91 % survival rate was observed. Molecular analyses on regenerated plantlets revealed the existence of a 71.66 % genetic polymorphism. Furthermore, morphological variation was confirmed by the presence of variegated individuals in regenerated plantlets. The proposed protocol can be useful in subsequent vanilla genetic improvement works.

STUDIES ON NATURAL DIVERSITY AND IN VITRO BEHAVIOR OF RARE INDIAN MEDICINAL HERB 'SAFED MUSLI' (CHLOROPHYTUM BORIVILIANUM)

Chlorophytum borivilianum Sant. et Fernand. (‘Safed Musli’), belonging to monocotyledonous family Liliaceae. It is distributed throughout the tropical and sub- tropical parts of the world. In India it has been reported growing in parts of Rajasthan, Madhya Pradesh, Jharkhand, Chhattisgarh, Maharashtra and Gujarat. It is an endangered Indian medicinal herb, valued for its tuberous roots reputed to have aphrodisiac properties. The plant is of economic importance in India since its dried roots are currently sold in the market at a price of Rs. 1500/- (US$30) per kilogram. Due to large-scale and indiscriminate collection of wild material and insufficient attempts either to allow its replenishment or its cultivation, C. borivilianum is rapidly disappearing. The natural regeneration of this herb is through tuberous roots that have become scarce in nature. It is therefore necessary to understand genetic structure of its natural populations in view of aiming at conservation and improvement strategies. In present study seven accessions of C. borivilianum were collected from different geographical regions of India were assessed for their natural diversity and in vitro behavior. The accessions exhibited significant variations in selected parameters of leaf growth, stomatal frequency, flowering and yield of root tubers. Accessions PBL-4, PBL-6 and PBL-7 outperformed the growth and yield parameters as compared to others. Higher magnitude of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) was recorded for yield per plant and leaf characteristics. More than 92.0% habitability was recorded for all the traits studied except stomatal frequency and number of flower, the other traits have positive correlation with yield per plant. In vitro response of these accessions also varied significantly, best shoot multiplication rate was obtained in PBL-4 and PBL-3 followed by PBL-2 and PBL-5. The per cent rooting in vitro derived shoots was maximum in PBL-4 and minimum in PBL-1. The present study will be helpful in selection of accessions/s for both ex situ and in situ conservation strategies and also for mass propagation of this medicinal herb.

Vegetative Propagation Studies in Myrica esculenta (Kafal) - A Non-Legume Nitrogen Fixing Species

Myrica esculenta is a wild nitrogen fixing tree, growing naturally in the forest edges at high elevation rain fed areas. This species is generally propagated via seeds but physical dormancy caused by impermeable seed coat causes an unreliable germination pattern. In the present study different types of cuttings were collected and planted in an open side area at Khirsu as well as in mist chamber after treating with different hormonal (IBA) doses i.e. 1000 ppm; 2000 ppm; 4000 ppm; 6000 ppm and one set was soaked in water and kept as control. No rooting was observed from any type of cutting however, only few cuttings at 4000 ppm IBA treatment in the June month were sprouted and died after three weeks of transplanting. In case of air layering, maximum roots were sprouted in the air layered treatments done during post summer or rainy season whereas, air layered done during winter season or pre summer season, no response was observed. Maximum (15.83%) rooting was recorded in the 4000 ppm IBA followed by 6000 ppm (9.17%), 2000 ppm (6.67%) and minimum in 1000 ppm (4.17%) treatments. In this study overall 7.17 per cent rooting was recorded in first year and 1.67 per cent in second year. The air layering done in the VMG at Dehradun all air layered branches except control showed rooting and better performance was recorded in 4000 ppm IBA than other. Both seed and air layered raised plants when planted in the field their growth and survival percentage was almost similar.

Root explant produces multiple shoot from pericycle in Psoralea corylifolia – a leprosy destroyer medicinal plant

Babchi (Psoralea corylifolia L.) is a rare medicinal plant. It has been considered to be efficacious in leprosy and hence given the name ‘Kushtanashini’ (leprosy destroyer) in Ayurveda. The high death rate in wild along with aimless and unlawful gathering and destruction of habitat put the plant in the category of endangered list. In this study a highly reproducible in vitro regeneration system in P. corylifolia using root segments was developed. The effect of different PGRs (Kin BA, and NAA) on the percentage of adventitious shoot induction and the number of shoot buds per root explant was assessed. The maximum response (65.57%) was observed in the media supplemented with 2.22μM BAP and 6.98μM Kin. The treatment had in average 39.67 number of shoot buds and 3.37 elongated shoots. Elongation response was best (92.0%) in MS+2.22μM BAP+6.98μM Kin media fortified with 2.89μM GA3 and 39.7μMPG, producing a mean of 9.3 elongated shoots with an average of 4.6cm length. An anatomical study showed that the origin of shoot buds were directly from pericycle of root. Elongated shoots were carefully excised and rooted on basal MS+4.92μM IBA+158.6μMPG, with 92 per cent rooting. Rooted explants survived in soil: vermicompost: vermiculite (1:1:1) with 100% success.

Influence of growing environment and rooting hormone on rooting of Acalypha (Acalypha hispidaBurm. F.) cuttings

In order to find out the favourable growing environment, a study was conducted in Acalypha cuttings in the presence or absence of rooting hormone in Andamans. After four months of planting, the cuttings planted under open environment exhibited significantly early sprouting and first leaf emergence, maximum number of roots, fresh and dry weight of roots per cutting, number of leaves, fresh and dry weights of leaves per shoot, shoot length, leaf size, leaf area and plant height. However, the maximum mean root length and number of shoots per cutting were significantly higher under shade-net house environment. Among the root characters, the maximum per cent increase over shade-net was obtained for fresh weight of roots per cutting, while it was for leaf area, among the shoot characters. Moreover, rooting hormone improved both the root and shoot growth of cuttings. Among the various treatment combinations, significant increase for the most of root and shoot parameters were recorded under open conditions with rooting hormone, followed by open condition without hormonal treatment. Cent per cent rooting of cuttings was observed for individual effects and their interactions. Minimum variation was recorded for leaf area and maximum variation for plant height.

Effect of Different Factors During In Vitro Growth and Multiplication in Groundnut Cultivar ‘JL-24’

During the present study effect of different factors were studied during in vitro growth and multiplication of adventitious shoot buds induced from de-embryonated cotyledon explants of groundnut cultivar ‘JL-24’. Optimum shoot multiplication rate of 7.0 folds and average shoot length of 3.0 cm was achieved on Murashige and Skoog’s (MS) medium supplemented with 2.0 mgl−1 6-benzylamino purine. During subsequent subculture after every 21 days, an initial shoot number of 3 shoots per explant produced a maximum of 21 shoots per explant after 9 weeks. Sucrose at 3.0 % concentration supported the optimum shoot multiplication rate of 7.0 folds. Lowering or increasing sucrose concentration from the control (3.0 %) proved detrimental for in vitro shoot multiplication and growth. In case of liquid MS medium (without agar) supplemented with 6-benzylamino purine (2.0 mgl−1) and sucrose (3.0 %) the multiplication rate was reduced by 1.5 folds (after 6 weeks) as compared to the semi-solid medium (with 0.8 % agar). Hyperhydricity was also observed in liquid medium. Shoots measuring 3.0–4.0 cm obtained from multiplying cultures were found suitable for rooting. Cent per cent rooting was achieved on 1/4th MS medium with sucrose (2.0 %), agar (0.8 %) and indoleacetic acid (0.5 mgl−1). Subsequent hardening and acclimatization led to 95 % survival of in vitro raised plants.

Effects of Type of Cutting, IBA and Bioinoculants on Rooting in Madhunashini (Gymnema sylvestre Retz.)

An experiment was carried out to study the effect of type of cutting, IBA and bioinoculants on rooting in madhunashini. Among the three types of cuttings, hardwood cuttings registered higher values for fresh (0.790g/cutting) and dry weight (0.650g/cutting) of sprouts, per cent rooting (6.66 %), fresh and dry weight of roots (0.037 and 0.030g/ cutting) and biomass production (0.682g/cutting). Among IBA and bioinoculant treatments, Azotobacter chroococcum recorded higher values for percentage sprouting (26.66 %) and rooting (9.99 %) as also for other root parameters; whereas, maximum fresh weight (0.863g/cutting) and dry weight of sprouts (0.740g/cutting), and, biomass production (0.759g/cutting) was observed in IBA 1000ppm treatment. Interaction effect of type of cutting, IBA and bioinoculants on fresh and dry weight of sprouts (2.438g and 2.084g, respectively) and biomass production (2.123g/cutting) was found superior in hardwood cuttings treated with IBA 1000ppm. Percentage of rooting (13.33 %) was better in hardwood cuttings treated with Azotobacter chroococcum. Therefore, among the various treatments tested, hardwood cuttings treated with Azotobacter chroococcum are the best for propagation through cuttings.

Vegetative propagation of Dalbergia sissoo: effect of growth regulators, length, position of shoot and type of cuttings on rooting potential in stem cuttings

The effect of auxins (IAA or IBA at 100, 200, 500 mg·L−1) on rooting and sprouting parameters differed significantly (p < 0.05). Rooting and sprouting percentages were higher in some treatments while other parameters were significantly higher in other treatments. The results of the present study revealed that rooting was significantly (p < 0.05) affected by the length of cuttings, as well as the position of shoots and type of cuttings. On average, 86.0 per cent rooting was observed in the 30-cm long cuttings compared to the other two lengths of cuttings, i.e., 20 and 25 cm, irrespective of any auxin treatment. In a control set, without any auxin treatment, a maximum of 60.0% rooting was recorded in the 30-cm long cuttings and a minimum of 40.0% of the cuttings rooted in the 20-cm long cuttings. Similarly, cuttings collected from the lower and upper portions of shoots resulted in 72.5 and 52.5 per cent rooting respectively, irrespective of auxin treatments. Maximum rooting was observed in the lower portion (40.0%) of cutting compared to the upper portion (30.0%) in the control set without auxin treatment. Leafless branches produced maximum (72.0%) rooting compared to the leafy cuttings (35.0%), irrespective of the auxin treatment. The leafy cuttings produces a minimum of 15.0% sprouting and rooting in the control set.

Propagation of Lagerstroemia Indica L.: Effect of IBA - Chemical formulations and cutting types on rooting behaviour of stem cuttings in relation to Biochemical changes

The study was conducted to ascertain the effect of IBA- chemical formulations and cutting types on rooting behaviour of Lagerstroemia indica during monsoon and spring seasons. The cuttings taken in monsoon (August) performed remarkably better than those taken in spring (March). Application of 0.4% IBA + 1% captan + 2% sucrose- talc registered the best sprouting (68.89%), rooting (75.56%) and root characteristics. The lateral cuttings resulted in significantly better rooting and root characteristics as compared to terminal and sub- terminal cuttings. Interaction effect revealed a maximum 86.67 per cent rooting when lateral cuttings were treated with the formulation of 0.4% IBA + 1% captan + 2% sucrose- talc and planted in monsoon. The study also revealed that cuttings with higher levels of total phenol, total carbohydrate and C/N ratio and low level of nitrogen exhibited better results.

Mass multiplication of Celastrus paniculatus Willd: An important medicinal plant under in vitro conditions via nodal segments

A rapid clonal propagation system has been developed for Celastrus paniculatus (Celastraceae) an important medicinal plant under in vitro conditions. Nodal explants from mature plant of this species were collected and cultured on MS medium supplemented with various concentrations (0.5, 1.0 and 2.0 mg l -1 ) of cytokinins (BAP and Kn) and auxins (IAA, NAA and 2, 4-D) alone and in various combinations under controlled condition of 16 hours of photoperiod and 8 hours dark period at a temperature of 25±2oC. The maximum number of shoots (8.9±0.5) along with hundred per cent bud break was recorded in the MS medium supplemented with 1.0 mg l -1 BAP. Most of the combinations of cytokinins with IAA induced the formation of less number of shoots. The in vitro regenerated shoots were excised aseptically and implanted on full and half strength MS medium without or with growth regulators (IAA, NAA and IBA) at the concentrations of 0.5 and 1.0 mg l -1 for rooting. MS half strength medium supplemented with 0.5 mg l -1 NAA proved best with hundred per cent rooting. The regenerated plantlets were successfully acclimatized in pots containing sterilized soil and sand mixture (3:1). The plantlets were then transferred to the field conditions. Seventy per cent of the regenerants survived well. (Journal of American Science 2010;6(7):55-61). (ISSN: 1545-1003).

Effect of Hormones on Direct Shoot Regeneration in Hypocotyl Explants of Tomato

This study was conducted for developing a high frequency regeneration system in two genotypes of tomato ( Lycopersicon esculentum Mill.), ‘Punjab Upma’ and ‘IPA-3’ for direct shoot regeneration from hypocotyl explants. The explants were excised from in vitro tomato seedlings and cultured on MS medium supplemented with different concentrations and combinations of hormones. Direct regeneration was significantly influenced by the genotype hormones combination and concentrations. The MS medium supplemented with (Kinetin 0.5 mg/l) and (BAP 0.5 mg/l) was found optimum for inducing direct shoot regeneration and number of shoots per explant from hypocotyl explants on this medium. Shoot regeneration per cent in ‘Punjab Upma’ and ‘IPA-3’ per cent was recorded to be highest i.e (86.02) and (82.57) respectively. Besides this, average number shoots per explant was also highest i.e (3.16) in case of ‘Punjab Upma’ and (2.93) in case of ‘IPA-3’. A significant decline was observed in percent shoot regeneration and average number of shoots per explant with increase in the hormonal concentration. Shoots were obtained and transferred to the elongation medium (MS + BAP 0.3 mg/l). Hundred per cent rooting was induced in separated shoots upon culturing on MS and ½ MS basal media. Hardening on moist cotton showed maximum plantlet survival rate in case of both genotypes. After hardening, plants were transferred to soil. Thus, a tissue culture base line was established in tomato for obtaining direct regeneration using hypocotyl as explants.

Variation in Shoot Anatomy and Rooting Behaviour of Stem Cuttings in Relation to Age of Donor Plants in Teak (Tectona grandis Linn. f.)

Shoot anatomical features viz., number of vessel elements, width and length of vessel and fibre elements were studied in relation to juvenility/maturity of teak (Tectona grandis Linn. f.). The findings show significant differences in these features, which indicates that variation in shoot anatomy can be used as a reliable indicator of juvenility/maturity in teak. The effect of age of donor plants and application of auxins on adventitious root formation in single noded leafy stem cuttings of teak was also investigated. Aging of donor trees suppressed rooting and sprouting of cuttings, but increased callus formation at the base of cuttings. Per cent rooting and per cent sprouting in cuttings decreased as age of donor plants increased from 2-months to 15-years and up to 30-years. IBA treatment promoted per cent rooting as well as per cent sprouting, NAA promoted only rooting and it suppressed sprouting. The effect of auxin treatment on rooting and sprouting of teak stem cuttings varied with the age of donor plants. Auxin and its concentration, which suppressed rooting and sprouting in cuttings of younger donor plants, actually promoted rooting when cuttings were taken from more mature donor plants. It appears that the auxin requirement for causing and promoting rooting in teak cuttings increased with increasing age of donor plants. The higher auxin requirement for causing and promoting rooting in cuttings of older trees may be due to a decrease in the content on endogenous auxins or decreased sensitivity of aging tissues to rooting promoters and /or accumulation of inhibitory substances which inhibit rooting.

Study of rooting in stem cuttings of Khirk (Celtis australis Linn.)

Khirk (Celtis australis Linn.) is an important multipurpose tree species, which has a great potential in Social/Agroforestry practices in the North-Western Himalaya. Since seed regeneration is a problem, rooting cutting is one of the options for carrying mass multiplication programme in this valuable species. Experiments were therefore conducted to ascertain the effects of donor stage, pre-conditioning (girdling), cutting portion and auxin treatments on rooting behaviour of Khirk. Auxin IBA in 0.2-1.0% concentration mixed with or without other chemicals (5% sucrose + 5% captan) was used for the treatment of cuttings. The cuttings taken in rainy season (July) and from tree donors performed remarkably better than those taken in spring and pole/sapling stage, respectively. The sub-apical and the girdled cuttings resulted in significantly superior rooting and root quality as compared to the apical and non girdled ones. Further, interaction effect revealed a maximum 90 per cent rooting when girdled cuttings from sub-apical portion were treated with 0.4% IBA-talc formulation in monsoon season.

Vegetative propagation of Himalayan Yew (Taxus baccata Linn.) through branch cuttings

The study was conducted to determine the effect of various chemicals including auxins, crown position, cutting portion and preconditioning (girdling) treatments on rooting behaviour of Taxus baccata - a taxol yielding tree of moist temperate Himalaya. Application of 0.75% IBA + 5% captan + 5% sucrose in August resulted in highest 72.22 per cent rooting in the species. The girdled cuttings produced significantly higher rooting than non-girdled ones. Similarly, the lower portion of cuttings resulted in significantly better success as compared to upper ones.

High frequency axillary shoot proliferation and plant regeneration from cotyledonary nodes of pomegranate ( Punica granatum L.)

A complete protocol is presented for in vitro regeneration of pomegranate ( Punica granatum L.), a tropical fruit tree, using cotyledonary nodes derived from axenic seedlings. Shoot development was induced from cotyledonary nodes on Murashige and Skoog (1962) (MS) medium supplemented with 2.3–23.0 μM benzyladenine (BA) or kinetin (Kn). Both type and concentration of cytokinin significantly influenced shoot proliferation. The maximum number of shoots (9.8 shoots/explant) was developed on a medium containing 9.0 μM BA. Shoot culture was established by repeatedly subculturing the original cotyledonary node on a fresh batch of the same medium after each harvest of the newly formed shoots. In vitro raised shoots were cut into nodal segments and cultured on a fresh medium for further multiplication. Thus, from a single cotyledonary node about 30–35 shoots were obtained in 60 days. Shoots formed in vitro were rooted on half-strength MS supplemented with 0.054–5.4 μM naphthaleneacetic acid (NAA). However, a medium containing 0.54 μM NAA resulted in the highest per cent rooting of shoots and significantly higher number of roots than other concentrations. Plantlets were successfully acclimated and established in soil.