Effect of Thidiazuron, NAA and BAP on in vitro propagation of Alstroemeria aurantiaca CV. ‘Rosita’ from shoot tip explants

The objective of the study was to evaluate the potency of Thidiazuron (TDZ) as a plant growth regulator when compared to combined auxin (NAA) and cytokinin (BAP) in evoking morphogenic responses from Alstroemeria aurantiaca cv. ‘Rosita’ shoot tip explants. Shoot tips cultured on basal medium devoid of any plant growth regulators (PGRs) only increased slightly in length and formed only 1 leaf per shoot during the culture period. The addition of various PGRs to the induction or culture medium significantly influenced the number and length of shoots as well as the number of leaves formed. While low concentrations of TDZ (0.1 μM) had no significant effect and high concentrations (5.0 μM) were inhibitory, medium concentrations (0.4‐1.0 μM) significantly increased the number and length of shoots as well as the number of leaves formed from the explants. The longest shoots were formed from explants cultured in media supplemented with 1.0 μM TDZ. Slightly better but comparable responses were observed from explants cultured on media supplemented with 1.0 mg/L BAP and low concentrations (0.01 mg/L) of NAA. The explants cultured in 1.0 mg/L BAP + 0.01 mg/L NAA formed the greatest number of shoots while those cultured in 1.0 μM TDZ formed the greatest number of leaves/ ex‐plant. Increasing the NAA concentration to 0.1 mg/L and combining this with either 1.0 mg/L BAP or 1.0 μM TDZ depressed shoot formation and shoot length. In conclusion, TDZ at concentrations between 0.4 and 1.0 μM were just as effective as combined auxins (NAA) and cytokinin (BAP) in evoking morphogenic responses from Alstroemeria aurantiaca cv. ‘Rosita’ shoot tip explants.Key Words: Thidiazuron, Alstroemeria aurantiaca, explant

Molecular characterization of potato (Solanum tuberosum L.) genotypes using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) markers

19 random amplified polymorphic DNA (RAPD) and five Inter-simple sequence repeat (ISSR) primers were used to characterize 35 potato accessions originating from Mexico, Europe and U.S.A, with the aim of generating information on the genetic diversity and relationship among the genotypes for better exploitation in breeding programs. A total of 222 and 82 loci were generated by the RAPD and ISSR primers, respectively. Both RAPD and ISSR primers revealed 81.45 and 82.98% polymorphism, respectively. Mantel test showed no correlation between RAPD and ISSR (0.27), RAPD and RAPD + ISSR (0.47) similarity matrices. However, a high level of correlation (0.74) was observed between ISSR and RAPD + ISSR similarity matrices. The ISSR marker was found to be more efficient compared to RAPD marker, thereby influencing more the consensus data. The use of consensus data generated more information related to genetic diversity in potato. RAPD and ISSR markers successfully differentiated between the potato accessions and subgrouped the genotypes based on origin. Information on genetic diversity and relationships will be useful in the selection of parents and mapping studies.Keywords: Solanum tuberosum L., random amplified polymorphic DNA (RAPD), inter-simple sequence repeat (ISSR), genetic diversity, relationship

Effect of Thidiazuron, Benzylaminopurine and Naphthalene Acetic acid on In vitro propagation of Tuberose (Polianthes tuberosa L.) from shoot tip explants

Tuberose (Polianthes tuberosa L.) is an important export crop among small-scale farmers in Kenya. One of the main challenges facing production and marketing of good quality Tuberose cut flowers is the lack of clean planting material as the resource-poor farmers multiply their own propagules. The main objective of the present study was to evaluate the potential of Thidiazuron (TDZ), a phenyl urea, benzylaminopurine (BAP), a cytokinin and naphthalene acetic acid (NAA), an auxin, on in vitro propagation of tuberose from shoot tip explants. No multiple shooting was observed in any of the treatments tested. Results from the study indicated that TDZ, at low concentrations, was more potent than BAP in increasing shoot length and quality as well as the number of leaves per shoot. However, TDZ at high concentration (5 µM), was toxic leading to death of the shoot explant. Inclusion of NAA in media either supplemented with TDZ or BAP led to formation of calli, which did not differentiate further. Keywords:Thidiazuron; Benzylaminopurine; Naphthalene Acetic acid; propagation of Tuberose; Polianthes tuberosa L.JAGST Vol 6(1) 2004: 48-5

In vitro Propagation of Ornithogalum saundersiae: potential of Thidiazuronas a chemical of choice.

The objective of the study was to evaluate the efficacy of Thidiazuron (TDZ) as a plant growth regulator in evoking morphogenesis, whole plant regeneration and subsequent rooting and bulbing from shoot tip cultures of Ornithogalum saundersiae L. Shoot tip explants maintained on MSO (basal medium devoid of any plant growth regulators), formed only one shoot over the 10-week period of culture, which also failed to root or form bulbs. Inclusion of TDZ at various concentrations (0.1-5.0 &#956M) promoted direct adventitious shoot proliferation. Most of the shoots subsequently formed roots and bulbs when transferred to MSO. Addition of naphthalene acetic acid (NAA) to the culture medium inhibited shoot formation causing the shoot tip explants to brown and die after about 7 days of culture without further growth, development or callus formation. Benzylaminopurine (BAP), on the other hand, slightly improved shoot formation above the controls, although subsequent rooting and bulbing were low. Of significance was the synergistic effects of BAP and NAA which, in combination, improved shoot proliferation, as well as subsequent root and bulb formation from the shoot tip explants to levels comparable to those of explants cultured in TDZ at 0.1-0.4 &#956M concentration range. In summary, TDZ at 5 &#956M concentration was more effective, but at lower concentrations (0.1-1.0 &#956M) was just as effective as combined NAA + BAP in eliciting morphogenic responses from shoot tip explants of Ornithogalum saundersiae L.Keywords:Ornithogalum saundersiae; Thidiazuron (TDZ); propagationJAGST Vol 6(1) 2004: 60-6

Effect of Thidiazuron, NAA and BAP on in vitro propagation of Alstroemeria aurantiaca CV. ‘Rosita’ from shoot tip explants

The objective of the study was to evaluate the potency of Thidiazuron (TDZ) as a plant growth regulator when compared to combined auxin (NAA) and cytokinin (BAP) in evoking morphogenic responses from Alstroemeria aurantiaca cv. ‘Rosita’ shoot tip explants. Shoot tips cultured on basal medium devoid of any plant growth regulators (PGRs) only increased slightly in length and formed only 1 leaf per shoot during the culture period. The addition of various PGRs to the induction or culture medium significantly influenced the number and length of shoots as well as the number of leaves formed. While low concentrations of TDZ (0.1 μM) had no significant effect and high concentrations (5.0 μM) were inhibitory, medium concentrations (0.4‐1.0 μM) significantly increased the number and length of shoots as well as the number of leaves formed from the explants. The longest shoots were formed from explants cultured in media supplemented with 1.0 μM TDZ. Slightly better but comparable responses were observed from explants cultured on media supplemented with 1.0 mg/L BAP and low concentrations (0.01 mg/L) of NAA. The explants cultured in 1.0 mg/L BAP + 0.01 mg/L NAA formed the greatest number of shoots while those cultured in 1.0 μM TDZ formed the greatest number of leaves/ ex‐plant. Increasing the NAA concentration to 0.1 mg/L and combining this with either 1.0 mg/L BAP or 1.0 μM TDZ depressed shoot formation and shoot length. In conclusion, TDZ at concentrations between 0.4 and 1.0 μM were just as effective as combined auxins (NAA) and cytokinin (BAP) in evoking morphogenic responses from Alstroemeria aurantiaca cv. ‘Rosita’ shoot tip explants.Key Words: Thidiazuron, Alstroemeria aurantiaca, explant

Efficacy of thidiazuron in In vitro propagation of carnation shoot tips: Influence of dose and duration of exposure

One of the main challenges facing production of good quality cut flowers is the lack of clean planting material especially among resource poor farmers who resort to multiplying their own propagules with detrimental results. Carnation (Dianthus caryophillus   L. cv. Yair) is an important export crop among farmers in Kenya. Carnation production, however, is constrained by lack of clean planting materials. The main objective of this study was to evaluate the potency of thidiazuron (TDZ), a phenyl urea, in evoking morphogenic response in vitro compared to combined auxin (NAA) and cytokinin (kinetin) from shoot tip explants of carnations as one possibility of producing en mass clean planting materials. In addition, the study was instituted to determine the optimum concentration and duration of exposure of TDZ in the number, length and general quality of shoots formed. Results from the study indicate that TDZ, at low concentrations of 0.1-1 μM, was just as effective as 0.2 mg-1 L NAA + 0.2 m-1 L kinetin in improving the number, length and quality of shoots regenerated from the explants cultured in vitro. Although multiple shoots were formed from explants cultured on media supplemented with high doses of TDZ (5 μM), they were dwarfed and of a poorer quality. Prolonged exposure of carnation shoot tip explants to high concentrations of TDZ was detrimental to plant regeneration. Sufficient morphogenic response could be achieved by exposing the explants to 1-5 μM TDZ for short durations of 3-10 days with subsequent transfer to MS basal medium devoid of any plant growth regulators