Agrobacterium mediated genetic transformation and regeneration in elite rice (Oryza sativa L.) cultivar BRRI dhan56

Agrobacterium-mediated genetic transformation of rice (Oryza sativa L.) cultivar BRRI dhan56 was  carried out in this study. Agrobacterium tumefaciens strain LBA 4404, which harbors the plasmid pIG121  that carries the genes for ß-glucuronidase gene, served as a reporter gene in the histochemical assay and  the neomycin phosphotransferase ΙΙ (NPT ΙΙ) gene for the identification of resistance to kanamycin was  used for genetic transformation. Twenty days old embryogenic calli from mature embryos of highly  regenerating rice cultivar BRRI dhan56 were used to co-cultivate with 0.8 to 0.9 OD600 Agrobacterium  for 25 min and the cultured was continued on agar medium for this study. The transformed colonies were selected by using 50 mg/L kanamycin and 50 mg/L rifampicin and confirmed by colony PCR. The PCR  positive colonies were isolated to transform by using calli of indica rice cultivar BRRI dhan56. Putative  leaf and root segments from  plantlets obtained from transformation experiment with the plasmid pIG121  were GUS positive. Integration of the introduced gene into the genome was  demonstrated by PCR. The  maximum transformation efficiency of 32% was obtained by using 500 mg/L cefotaxime as a  bacteriostatic agent to inhibit growth of Agrobacterium. In this study, 100 µM acetosyringone in  co-cultivation medium and co-cultivation for 3 days were the optimum conditions for maximum  transformation. The expression of GUS gene revealed that the calli were successfully transformed. The  results of this study would be an effective tool for crop improvement and gene-function studies on the  model monocot plant rice. Key words: Agrobacterium, Oryza sativa L., acetosyringone, β-glucuronidase, cefotaxime, plasmid, phosphotransferase, rice, transformation. Abbreviation: GUS, β-Glucuronidase; PCR, polymerase chain reaction; MS, Murashige and Skoog; 2,4-D, 2,4-dichlorophenoxyacetic acid; MCI, callus induction medium; OD, optical density; NAA, 1-naphthaleneacetic acid; BAP, 6-benzylaminopurine. 

MULTIPLE SHOOT REGENERATION IN DENDROBIUM FIMBRIATUM HOOK AN ORNAMENTAL ORCHID

ABSTRACT The prime objective of the present study was to optimize and develop efficient regeneration protocol for in vitro germination, micropropagation and root induction of the orchid plant Dendrobium fimbriatum. Three investigated culture media were Phytamax (Sigma, USA; PM), Murashige and Skoog (MS) and Modified Vacin and Went (MVW) were used. Among these media PM was found to be the most effective medium for germination of orchid seedlings. In this medium, the germination rate was 100 percent. Twelve different combinations of plant growth regulators were tested for the elongation of germinated seedlings. It was revealed that MS medium fortified with 2.0 mg/l 6-benzylaminopurine (BAP) and 0.01 mg/l indole-3-butyric acid (IBA) was the most effective for shoot elongation. The average elongation rate was 4.10 cm after 30 days of culture. Sixteen different combinations of plant growth regulators were used for induction and elongation of adventitious shoots from the nodal zone of shoot explants. MS medium supplemented with 1 mg/l BAP and 0.5 mg/l Picloram was proven to be the best for multiple shoot formation and elongation. In this medium the average number of induced shoots per explant was 4.35. Furthermore, shortest duration (16 days) for shoot induction was recorded on this medium. Half MS medium supplemented with 1.0 mg/l indole-3-acetic acid (IAA) was found suitable for effective induction and growth of adventitious roots on the micro-propagated orchid plantlets

In vitro propagation of Citrullus lanatus Thumb. from nodal explants culture

A standard protocol was established for rapid in vitro propagation of watermelon (Citrullus lanatus Thumb.) from nodal explants of field grown plant. Multiple shoot proliferation was achieved from nodal explants on MS medium supplemented with 1.0 mg/l BAP + 0.2 mg/l NAA within 30 days of inoculation. The elongation of shoots was obtained on the same medium. Highest percentage of root induction was achieved on MS medium supplement with 1.0 mg/l IBA within 25 days of culture. Well rooted plantlets were transferred to small pots and after proper acclimatization the plantlets were transplanted in the field condition, where 80% plantlets were survived and grew successfully

VARIABILITY AND INTERRELATIONSHIP AMONG YIELD AND YIELD CONTRIBUTING CHARACTERS IN ONION (ALLIUM CEPA L.)

A study was conducted using seven varieties of onion (Allium cepa L.) and observations were recorded on yield and yield components in order to obtain informations on genetic variability and character association of onion. Higher genotypic coefficients of variations were recorded in number of seeds per scape (NSPS), final plant height (FPH), final scape height, fresh weight of bulb and bulb length. These characters also exhibited high heritability along with high genetic advance as percentage of mean. Phenotypic correlation coefficients showed that bulb length, bulb diameter and scape diameter were positively and significantly correlated with fresh weight of bulb. The number of seeds per scape, final scape height, final plant height and number of pseudostem branches at maximum flowering stage were also positively and significantly correlated with seed yield per scape

HIGH FREQUENCY IN VITRO PROPAGATION OF ADHATODA VASICA NEES THROUGH SHOOT TIP AND NODAL EXPLANTS CULTURE

An efficient protocol for in vitro propagation of Adhatoda vasica Nees was established using shoot tip and nodal explants from field grown mature plant. Proliferation of multiple shoots was achieved on MS medium supplemented with different concentrations and combinations of cytokinins (0.5-4.0 mg/l) and auxins (0.1-1.0 mg/l). Maximum number of shoots per explant (13.0) was obtained on MS medium supplemented with 2.0 mg/l BAP + 0.2 mg/l NAA. Among two types of explants used in this study, nodal explants showed better response in respect of multiple shoot production. The elongated shoots were excised and subcultured for rooting on MS medium supplemented with different concentrations of auxins (IBA and NAA). Highest 80 % rooting was achieved; and three to four roots per shoot were recorded in medium with 1.0 mg/l IBA within 4 weeks of culture. The in vitro raised plantlets were acclimatized and successfully transferred to natural condition in pot. The regenerated plants were healthy, uniform and identical to the donor plants and the survival percentage was 80%. Key words: Micropropagation, Adhatoda vasica, shoot tip, nodal explant

Stable integration, expression and inheritance of the <i>ferritin </i>gene in transgenic elite <i>indica </i>rice cultivar BR29 with enhanced iron level in the endosperm

26-31Rice (Oryza sativa L.) is a major crop providing staple diet for more than half of the world's population, but it does not fulfill the recommended daily dietary allowance. Moreover, milling of rice grain causes considerable losses of nutrients,including iron. Iron deficiency is a global nutritional problem. About 3.5 billion people in the developing world suffer from iron-deficiency anemia, of which 50% is dietary in origin. To increase iron storage in rice, we introduced the ferritin gene driven by an endosperm-specific glutelin promoter into a Bangladeshi rice cultivar, BRRl Dhan 29 (BR29), using the biolistic method. Analysis demonstrated integration, inheritance and expression of the ferritin gene up to the T3 generation.The iron content in seeds was estimated by using the ICP (Inductively Coupled Argon Plasma) Spectrometer. All transgenic plants accumulated higher levels of iron in the grain, with as much as 9.2 mg/kg versus the control (3.8 mg/kg). A histochemical reaction of the thin microtome section revealed the presence of iron in the endosperm cells of the transgenic grain. This finding suggests that homozygous rice lines with enhanced iron content developed by genetic engineering could help overcome iron deficiency in developing countries