Optimization of callus culture and shoot multiplication ofAsparagus densiflorus

The effects of different growth regulators on induction and growth of callus ofAsparagus densiflorus cv. Sprengeri were studied. Calluses grew more rapidly on Murashige and Skoog basal medium supplemented with 5.4 μM p-chlorophenoxyacetic acid (pCPA) and 4.4 μM 6-benzylaminopurine (BA) (medium 1) as compared to the same medium with 11.3 μM 2,4-dichlorophenoxyacetic acid (2,4-d) and 4.6 μM kinetin (medium 2). Calluses on medium 1 were soft and friable, whereas, compact, hard calluses originated on medium 2. Different concentrations and combinations of BA and/or kinetin were also used to study their effects on shoot regeneration. Kinetin was found to be less effective than BA in the initiation of shoots (1.8 shoots/callus). High numbers of shoots were produced in the presence of 0.4 μM BA alone (3.3 shoots/callus). The addition of ancymidol (5 μM) in MS with 0.4 μM BA enhanced multiplication of shoots (9.8 shoots/explant) and also produced well-developed crowns.     

Plant genotype and growth regulators interaction affecting in vitro morphogenesis of blackberry and raspberry

The morphogenic response of somatic (leaf and petiole) and de-differentiated tissue (callus) of two blackberry (Rubus fruticosus) and one raspberry (Rubus idaeus) cultivars have been studied in vitro. With the aim to induce regeneration the effect of two sets of plant growth regulator (PGR) combinations (high cytokinin/auxin ratios and high auxin/cytokinin ratios) in Murashige and Skoog basal medium, were analysed. The three cultivars were characterised by a qualitatively different morphogenic response to the PGR combinations. Raspberry adventitious shoot regeneration from somatic tissue was improved by the 6-benzylaminopurine (BAP)/indol-3-butyric acid (IBA) combinations. On the contrary, shoot regeneration of both blackberry cultivars was reduced by high concentrations of BAP and completely inhibited by BAP/IBA combination. Media supplemented with high auxin/cytokinin ratios promoted callus production and root differentiation according to genotype and type of auxin. All the genotypes responded to media supplemented with IBA. 2,4-dichlorophenoxyacetic acid induced good callus formation in blackberry, but was toxic to raspberry. Indirect shoot formation was observed only in callus of blackberry cultivar Hull Thornless cultivated on medium with 10 μM BAP, the same concentration able to trigger efficient direct shoot regeneration from leaf explants of the same cultivar. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of genotype, explant source, and plant growth regulators on indirect shoot organogenesis in Dieffenbachia cultivars

The capacity for indirect shoot organogenesis of leaf and root explants of four Dieffenbachia cultivars were examined on a modified Murashige and Skoog (MS; Physiol Plant 15:473–495, 1962) medium supplemented with different plant growth regulators in 112 combinations. Callus formation was only observed from leaf explants on MS supplemented with 1–10 μM thidiazuron (TDZ) and 0.5–1.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D) regardless of cultivars. The combination of 5 μM TDZ and 1 μM 2,4-D resulted in the greatest callus formation frequency among the four cultivars tested. Significant differences in callus and shoot formation from leaf explants were also observed among cultivars. Cultivars Camouflage, Camille, Octopus, and Star Bright produced green nodular, brown nodular, yellow friable, and green compact calli with corresponding maximum callus formation frequencies of 96%, 62%, 54%, and 52%, respectively. A maximum of 6.7 shoots/callus was observed in cv. Camouflage, followed by cvs. Camille and Star Bright at 3.7 and 3.5, respectively. Calli of cv. Octopus displayed no capacity for shoot organogenesis. Regardless of cultivar, callus formation was not observed on root explants. Regenerated shoots were successfully acclimatized in a shaded greenhouse condition with 100% survival.     

Embryogenesis and plant regeneration from unpollinated ovary culture of <Emphasis Type="Italic">Psoralea corylifolia</Emphasis>

Embryogenesis and plant regeneration was achieved from callus cultures derived from unpollinated ovaries of Psoralea corylifolia L. Callus was initiated from unpollinated ovaries on Murashige and Skoog (MS) medium supplemented with 2.2 μM N ⁶-benzyladenine (BA) and various concentrations of α-naphthaleneacetic acid (NAA (2.7 to 10.7 μM) or 2,4-dichlorophenoxyacetic acid (2,4-D (2.3 to 9 μM) alone or in combination. Highly organized embryogenic callus induction, embryo development, proliferation and maturation were achieved on transfer of callus clumps to MS medium supplemented with NAA (0.27 μM) or 2,4-D (0.23 μM) alone or in combination with BA (2.2 to 8.8 μM). Addition of abscisic acid (ABA) (0.95 to 5.8 μM) to the medium enhanced average numbers of cotyledonary stage embryos, the maximum number (34.6 ± 0.7) being obtained on MS medium containing 0.27 μM NAA, 2.2 μM BA and 3.8 μM ABA. Embryos germinated on MS medium supplemented with BA (0 to 8.8 μM). MS medium containing gibberellic acid (GA₃ (0.29 to 5.8 μM) enhanced embryo germination frequency, the highest frequency (66.7 %) occurring on MS medium containing 2.2 μM BA and 4.3 μM GA₃. Effect of several concentrations (3.0 to 6.0 %) of sucrose or maltose was also observed on germination of embryos. MS medium enriched with maltose supported high frequency of embryo germination.     

Plantlet Regeneration via Multiple Shoot Induction in Indian Cultivars of Lucerne (Medicago sativa L)

An efficient protocol has been developed for in vitro plant regeneration via multiple shoot induction in lucerne (Medicago sativa L). Shoot tips from in vitro grown 5–6 days old seedlings of 3 cultivars, LLC-3, Chetak and RL-88 were used as explants for multiple shoot induction on MS medium supplemented with cytokinins. Maximum of 14 shoots per apical meristem were observed in case of cv Chetak on MS medium supplemented with BAP (12.6 μM) and KN (9.3 μM). Shoot elongation on MS medium supplemented with GA (5.8 μM), while root induction was achieved on MS medium supplemented with IAA (11.4 μM) and activated charcoal (2.0 g l^?1). Tissue raised plants showed 75% survival after transfer to soil under field conditions.     

In vitro propagation of Gladiolus hybridus Hort.: Synergistic effect of heat shock and sucrose on morphogenesis

Three cultivars (cvs.) of Gladiolus hybridus Hort., namely ‘Her Majesty’, ‘Aldebaran’ and ‘Bright Eye’ were successfully micropropagated. The cultures were established using intact cormels or segments of cormels and inflorescence axes on Murashige and Skoog (1962; MS) medium. The response depended on media supplements; both callus formation or direct induction of shoot buds was observed. Shoot differentiation from callus could be obtained on MS medium containing 1.0 μM BA (6–benzyladenine) and 10.0 μM NAA (α-naphthalene acetic acid) in all three cultivars. The same could be achieved by giving a heat shock (HS; 50 °C, 1h) to callus cultures (in case of ‘Her Majesty’ and ‘Aldebaran’ only) maintained on the basal medium. In these two cultivars, high sucrose concentration (0.232, 0.290 or 0.348 M) also favoured growth and proliferation of shoot cultures on a plant growth regulator-free medium at 20 °C in comparison to the cultures kept at 25 °C. On the other hand, shoot cultures maintained on the basal medium at 25 °C containing normal (0.058 M, i.e., 2.0%, w/v) sucrose concentration responded similar to those maintained at 20 °C on a high sucrose medium; reduced response was observed on normal sucrose containing medium at 20 °C. Heat shock enhanced shoot proliferation in the cultures maintained on basal medium, but induced prolific rooting in shoot cultures, within 5 days of HS, on high sucrose (optimum 0.232 M) medium. While the number of roots increased at higher sucrose concentrations in the medium in case of cvs. ‘Her Majesty’ and ‘Aldebaran’, the same was found to be independent of sucrose concentration in cv. ‘Bright Eye’. Generally the rooted plants produced on high sucrose (0.232 M) medium in comparison to medium with normal sucrose concentration showed better survival (ca. 90% as against 40%) in the soil. This revised version was published online in June 2006 with corrections to the Cover Date.     

以根为外植体建立大蒜的组织培养体系

以国内4个大蒜栽培品种为材料,建立了以根为外植体的再生体系。将蒜瓣去皮后灭菌消毒,萌发后选取苗龄为5~7 d的无菌苗的根接种到含不同激素配比的培养基中进行愈伤组织诱导,发现MS+2,4-D 1 mg/L+2ip 0.1 mg/L组合愈伤诱导效率最高,平均为56.06%;愈伤组织经过2~3次继代培养,选取胚性愈伤组织置于不同分化培养基上进行培养,2~3个月后可见小芽产生,分化培养基为MS+KT 1 mg/L时,植株再生效率最高,平均达到35.01 %。本研究建立了一种以根为外植体的高效的大蒜愈伤诱导和再生体系,为大蒜遗传转化体系的建立打下良好基础。     

Embryogenic callus formation,growth and regeneration in callus and suspension cultures of Miscanthus x ogiformis Honda Giganteus' as affected by proline

The effects of proline additions to culture systems of Miscanthus x ogiformis Honda Giganteus' were investigated. Proline was added in concentrations of 0, 12.5, 25, 50, 100 or 300 mM to the callus induction and suspension culture media containing either Murashige and Skoog or N6 basal salts and 22.6 μM 2,4-dichlorophenoxyacetic acid. Shoot apices and leaves from in vitro-propagated shoots, and immature inflorescences from greenhouse-grown plants were used as explants for callus induction and formation. Suspension cultures initiated from embryogenic callus of immature inflorescences were used to test the effect of proline in suspension cultures. The proline additions affected the formation of embryogenic callus and the growth of suspension cultures. Improvements depended on the proline concentration and the basal salts of the medium. Addition of 12.5 to 50 mM proline to callus induction medium with Murashige and Skoog salts increased embryogenic callus formation on shoot apices and leaf explants while proline had no effect on embryogenic callus formation in medium with N6 salts. Increased growth with increasing proline concentration was obtained in suspension aggregates grown in medium with N6 salts, whereas proline only increased growth of suspension aggregates grown in medium with Murashige and Skoog salts at concentrations of 12.5 or 25 mM. A stimulating effect of proline on plant regeneration was observed in short-term cultures of callus as well as in long-term cultures of suspension aggregates. An optimum proline concentration for plant regeneration was found at 12.5 mM. This revised version was published online in June 2006 with corrections to the Cover Date.     

In vitro culture of Safflower L. cv. Bhima: initiation,growth optimization and organogenesis

Callus induction and in vitro plantlet regeneration systems for safflower (Carthamus tinctorius L.) cv. Bhima using root, hypocotyl, cotyledon and leaf explants were optimized by studying the influence on organogenesis of seedling age, media factors, growth regulators and excision orientation. Supplementation of the medium with an auxin: cytokinin ratio < 1 enhanced the growth rate of callus cultures; however, for 2,4-D the ratio was > 1.34–11.41 μM concentrations of growth regulators (IAA, NAA, BA and Kinetin) in the medium were found effective for callus induction and regeneration in all explants. The calli could be maintained over 32 months. BA (4.43 μM) combined with casein hydrolysate (10 mg l-1) yielded the highest rate of shoot production on hypocotyl (3–6) and cotyledon (5–7) explants and cotyledonary derived callus (4–8). More shoots were produced on explants cut from the most basal region of cotyledons from 5 to 7-day-old seedlings than from older seedlings or more distal cut sites. Apolar placement of explants, inhibited shoot regeneration. The shoot regeneration potential remained upto 7 months in calli developed on NAA + BA. Of three media tested, MS was superior to SH-M and B5. Rooting of shoots was not efficient; 42% of the shoots were rooted on MS medium containing sucrose (7–8%) + IAA (2.8–5.7 μM). Capitula induction was observed in both callus mediated shoots on cotyledons and shoots on rooting medium with sucrose, IAA, NAA and IBA. Well developed plantlets were transferred to the field with a 34% success rate. This revised version was published online in June 2006 with corrections to the Cover Date.     

Histology of the Morphogenic Response in Thin Cell Layer Explants from Vegetative Tobacco Plants

The morphogenic response of thin cell layers (TCLs) from vegetativetobacco (Nicotiana tabacum L.) plants can be directed very preciselyby varying the concentrations of benzyladenine (BA) and -naphthaleneacetic acid (NAA) in the culture medium. Medium containing 1·6µM BA and 0·5 µM NAA was optimal for shootformation, concentrations of 0·5 µM BA and 1·6µM NAA were optimal for the induction of shoots and rootson the same explant, whereas concentrations of NAA higher than16 µM resulted in callus proliferation only. Polarityin the distribution of the shoot buds was observed, i.e. a switchfrom basal to apical shoot formation occurred with increasingNAA concentrations, suggesting basipetal transport of NAA. Histologicalexamination of TCLs on shoot induction medium revealed thatfirst cell divisions occurred within 2 d in cortical cells whichwere directly in contact with the medium along the longitudinalcut surface, and after 2 d in subepidermal cells along the lateraledges of the explants. Individual lateral buds originated fromone subepidermal and one or more epidermal cells, while apicalbuds originated from single subepidermal or cortical cells locateddirectly at the apical end of the explant. After culture ofTCLs for 2-3 d on root/shoot induction medium cells in the regeneration-competentsubepidermis elongated, while on callus induction medium subepidermalcells elongated and dedifferentiated. The regeneration systemas described in this study will be used to identify cells competentfor regeneration as well as for transformation.Copyright 1994,1999 Academic Press Nicotiana tabacum L., tobacco, thin cell layer explants, cell competence, shoot development, polarity     

In vitro callus induction and plant regeneration from leaf explants of Ruta graveolens L.

A protocol for multiple shoot bud induction and plant regeneration from leaf segment-derived callus of Ruta graveolens has been developed. Maximum organogenic callus induction frequency (70.6 ± 2.33%) was observed on Murashige and Skoog (MS) medium supplemented with 10 µM 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). Multiple shoot induction was achieved from the surface of the callus when transferred to shoot induction media (MS nutrients supplemented with 6-benzyladenine (BA), kinetin (Kn), indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and α-naphthalene acetic acid (NAA) in various concentrations and combinations). The highest shoot multiplication (92.3%) was observed on MS medium with 7.5 µM BA and 1.0 µM NAA. Regenerated shoots were rooted in vitro on MS containing 0.5 µM IBA. Plantlets with well developed root and shoot systems were successfully acclimated (90%) and established in earthen pots containing garden soil; they exhibited normal morphology and growth characteristics.     

Callus induction and plant regeneration in <Emphasis Type="Italic">Alternanthera philoxeroides</Emphasis>

To establish a successful in vitro plant regeneration system in Alternanthera philoxeroides (Mart.) Griseb, an orthogonal design was used to investigate the effects of three factors (plant growth regulators, explant types and dark treatment in initial-stage), each having three levels. The effects of these factors and levels on callus induction and shoot regeneration were quantitatively evaluated by analysis of variance. The experimental results showed that the callus induction was significantly affected by 2, 4-dichlorophenoxyacetic acid (2, 4-D), and shoot differentiation from subcultured pieces of callus was enhanced mostly by dark treatment in initial-stage. The optimal conditions for callus induction are obtained from the stem explants cultured on semi-solid Murashige and Skoog (MS) medium plus 2.2 μM BA and 2.2 μM 2, 4-D, with 20 days dark treatment in initial-stage. The highest frequency of shoot regeneration is obtained from the calli cultured on semi-solid MS medium plus 8.8 μM BA, without dark treatment in initial-stage.     

芝麻愈伤组织诱导与植株再生体系的建立

以芝麻栽培种(Sesamum indicum, 2n=26)、野生种(S. radiatum, 2n=64; S. schinzianum, 2n=64)及其远源杂交后代(S. schinzianum × S. indicum)为材料, 研究了不同基因型、外植体类型、激素种类及其浓度对芝麻愈伤组织诱导及植株再生的影响, 建立了芝麻愈伤组织诱导及高频植株再生的技术体系。结果表明, 6-BA/NAA激素组合有利于绿色紧密型愈伤组织的形成及分化; 最佳愈伤组织诱导及分化培养基为MS+ 0.1 mg·L^–1NAA + 2.0 mg·L^–16-BA+ 30 g·L^–1蔗糖。在该培养条件下, 野生种下胚轴愈伤组织的诱导率最高为97.50%, 分化率为94.02%; 栽培种下胚轴愈伤组织的诱导率最高为40.60%, 分化率为8.16%; 远缘杂交后代幼胚外植体愈伤组织的诱导率最高为46.67%, 分化率为89.29%。该研究结果为芝麻转基因技术体系的建立及新种质创制奠定了基础。     

Evaluation of regeneration potential of mature embryo derived callus in Indian cultivars of barley (Hordeum vulgare L.)

A protocol for plant regeneration in Indian cultivars of barley (Hordeum vulgare L.) has been developed using mature embryo culture. The influence of various auxins 2,4-D (2,4-dichlorophenoxyacetic acid), Dicamba (3,6-dichloro-o-anisic acid) and Picloram (4-amino-3,5,6-trichloropicolinic acid) on the callus induction and subsequent plant regeneration revealed highest percent of callus induction form cultivar (cv) BL 2 on MSB₅ medium (MS salts + B₅ vitamins) supplemented with 6 mg l^?1 Picloram, but maximum number of shoot buds (6–13) were regenerated on MSB₅ medium containing 0.5 mg l^?1 Picloram. Regenerated shoots were rooted on half-strength MSB₅ medium. Plantlets were successfully transferred to soil and grown to maturity in greenhouse. The effect of copper sulphate revealed significant improvement in callus induction and plant regeneration when the concentration of CuSO₄ was increased to 3 μM (30 times higher than normal MS medium) for cv BL 2. Regeneration potential differed for different cultivars of barley used, with highest for cv BL 2 and lowest for cv BH 924. We conclude that the Indian barley genotypes exhibit plant regeneration from mature embryo cultures. The protocol has potential application in barley improvement through genetic engineering.     

Effects of growth regulators and incubation period on in vitro regeneration of adventitious shoots from gerbera petioles

An effective system for in vitro regeneration of adventitious shoots from callus for the transformation or mutation of gerbera was developed. Callus was produced from petioles of the youngest 3–4 leaves detached from auxillary shoots produced in vitro. Induction medium, on which leaves were incubated over 3 or 6 days, contained 2.3 μM thidiazuron and 0.53 μM α-naphthaleneacetic acid. Explants were than transferred to one of three regeneration media with lower levels of growth regulators. Regeneration was quantified over four (4-weeks each) passages at the time of explant transfer to fresh medium. Direct shoot regeneration occurred during the first 4 weeks, and after these shoots were discarded a semi-compact organogenic callus was produced. Effectiveness of shoot regeneration depended on four criteria: the cultivar (three cultivars were tested), the sequence of passage on regeneration medium, the growth regulators in regeneration medium and the duration of the induction period. Regeneration potential from calli of all cultivars increased from the first to the fourth passage. Duration of the incubation period on induction medium (3 or 6 days) influenced regeneration to varying degrees, depending on the cultivar used and the regeneration medium contents. There were no differences between two of the regeneration media – B, containing 2.2 μM 6-benzyladenine and 0.3 μM indole-3-acetic acid and C, containing 4.4 μM 6-benzyladenine, 4.6 μM zeatin and 0.6 μM indole-3-acetic acid. Cultivar Mariola was the most productive and regenerated more than seven shoots per callus in the fourth passage. Regeneration on medium B was further evaluated on four additional gerbera cultivars. This revised version was published online in June 2006 with corrections to the Cover Date.     

Regeneration of salvia (<Emphasis Type="Italic">Salvia officinalis</Emphasis> L.) via induction of meristematic callus

Nodular meristematic callus was induced on the basal cut surface of apical shoot explants of salvia cultured on Murashige and Skoog (MS) medium supplemented with 4.5, 13.5, or 22.5 μM thidiazuron (TDZ). Cultures were incubated in the dark for 1 wk and then transferred to light conditions for 4 wk. A higher percentage of explants developing callus was observed on medium containing either 4.5 or 13.5 μM TDZ, although explants on 4.5 μM developed larger calluses. The callus was maintained on medium containing 4.5 μM TDZ and 0.45 mM ascorbic acid. Shoot differentiation, after each of three successive maintenance passages, was induced from callus grown on medium containing either 4.4 or 8.8 μM benzyladenine (BA). A greater number of shoots were harvested from callus differentiated on BA (4.4 or 8.8 μM) medium with 0.45 mM ascorbic acid added. Shoots developed roots on MS medium supplemented with 4.9 μM of indole-3-butyric acid. The addition of ascorbic acid to the shoot differentiation medium enhanced rooting, number of roots per shoot, and survival rate. Approximately 75% in vitro plantlets were acclimatized to ex vitro conditions. Histological investigations confirmed both adventitious meristem initiation during the callus induction phase, and subsequent organogenic shoot development on the differentiation medium. The novel protocol for the meristematic callus induction and plant regeneration in this study may be useful for biotechnological applications for salvia improvement via genetic transformation or mutagenesis and in vitro propagation approaches.     

<Emphasis Type="Italic">In vitro</Emphasis> propagation of an endangered plant species, <Emphasis Type="Italic">Thermopsis turcica</Emphasis> (Fabaceae)

This report deals with micropropagation of the critically endangered and endemic Turkish shrub, Thermopsis turcica using callus, root and cotyledonary explants. Callus cultures were initiated from root and cotyledon explants on MS medium supplemented with 0.5–20 μM NAA or 2,4-D. The root explants were found to be better in terms of quick responding and callusing percentages as compared to the cotyledons. Organogenic callus production with adventitious roots and shoots were obtained on MS medium with only NAA. The calli obtained with NAA, root and cotyledonary explants were cultured with BA and kinetin (2–8 μM) alone or in combination with a low level (0.5 μM) of 2,4-D or NAA. The best regeneration of shoots from root explants was observed on hormone-free MS medium. NAA with BA or kinetin in the medium improved shoot induction from the calli obtained with NAA. Maximum percentage of shoots (93.3%), maximum number of shoots (6.2) and maximun length of shoots (8.22 cm) were achieved from cotyledonary explants at 4 μM BA and 0.5 μM NAA. The presence of 0.5 μM or higher levels of 2,4-D in shoot induction medium inhibited the regeneration in T. turcica explants. 83% of in vitro rooting was attained on pulsed-IBA treated shoots. The regenerated plants with well developed shoots and roots were successfully acclimatized. Application of this study’s results has the potential to conserve T. turcica from extinction.     

High Frequency Induction of Multiple Shoots and Plant Regeneration from Cotyledonary Nodal Explant of Mung Bean [Vigna radiata (L) Wilczek]

An efficient protocol for shoot bud induction and proliferation employing half cotyledonary node with intact cotyledon explants derived from two-day-old seedlings of mung bean pre-conditioned on 6- benzylaminopurine (BAP) has been achieved. Explants were cultured for four weeks each on MS B₅ + 12.5 μM BAP and MS B₅ + 5 μM BAP +0.05 μM α-naphthaleneacetic acid (NAA ), respectively, as shoot bud induction and shoot elongation and proliferation media, gave the best regeneration response. The removal of the pre-existing buds from explants at 12 days in shoot bud induction medium led to enhanced regeneration response. Light microscopic observations on 14-day-old explants confirmed direct organogenesis route of regeneration. Elongated shoots (>2 cm) excised from the regenerating cultures were successfully rooted on half MS B₅ medium containing 2.46 μM indolebutyric acid (IBA). About 90% of the rooted plantlets, efficiently hardened in pots having soil and farm yard manure, flowered and produced pods with viable seeds upon reaching maturity.     

In vitro differentiation in callus cultures of moth bean,Vigna aconitifolia (JACQ) marechal

Callus cultures of two cultivars of Vigna aconitifolia (IPCMO-926, RDM-120) were raised and their growth and differentiation studied. In IPCMO-926 callus cultures, numerous shoot buds differentiated on MS medium with BA (0.4–22.2 μM) alone or in combination with IAA (5.7 μM). In RDM-120 best differentiation of shoot buds was observed on a medium with K (23.2 μM) and IAA (5.7 μM). Kinetin alone, however, induced rhizogenesis in callus cultures. In suspension cultures of IPCMO-926 embryoids differentiated on MS medium with K (0.5 μM) and 2,4-D (0.4 and 0.9 μM).     

Efficient shoot and root formation from cotton shoot apices

Successful shoot and root induction were obtained from shoot apices of two cotton (Gossypium hirsutum L.) genotypes, Nazilli 84S and Çukurova 1518, which are widely planted in Turkey. Plant tissue culture systems were established on Murashige and Skoog (MS) medium supplemented with various plant growth regulators using seven-day-old shoot apices as explants. The shoot apex size was of 2–3 mm; it contained the meristem and unexpanded leaves. Shoot apices were placed on MS plus vitamins and combinations of various plant hormones. The best regeneration responses were obtained for cv. Nazilli 84S (98%) on MS + 0.1 mg/l kinetin (KIN) + 1 g/l polyvinylpyrrolidone (PVP) and for Çukurova 1518 (94%) on MS + 0.1 mg/l KIN + 2 mg/l NAA + 1 g/l PVP. Including germination, all regeneration and rooting processes lasted only 5 weeks. The shoot apices of both genotypes developed successfully without intervening callus formation, and no significant differences between cultivars were found. All regenerated plants of both genotypes were phenotypically normal and set seeds. This shoot meristem-based rapid regeneration method can also be used in the cases of biolistic and Agrobacterium-mediated transformation.