Modified protocol to overcome in vitro recalcitrance of premature micro-shoots abscission by silver supplementation in Kinnow mandarin (Citrus nobilis L. × Citrus deliciosa T.)

The present study focused on alleviating the issue of premature abscission of micro-shoots emerged from the cultured nodal segments in Kinnow mandarin. To resolve the problem, explants of different maturity stages, culture media, growth regulator combinations and ethylene inhibitors (silver compounds) were evaluated. Hardwood stage was observed to be the most efficient explant maturity stage to boost the vigorous early shoot emergence on MS (Murashige and Skoog) medium. Addition of GA3 (Gibberellic acid) 10 mg L?1 resulted in delayed abscission. Further reduction in abscission rate and healthy shoot growth were observed when subculturing of micro-shoots was done on MS medium supplemented with BAP 2.5 mg L?1, GA3 10 mg L?1 and silver thiosulfate 5 mg L?1. This modified procedure could be effectively utilized for mass multiplication as well as crop improvement in Kinnow mandarin.

Strategies for vegetative propagation and viral cleaning of a miniature ornamental pineapple hybrid

This study assessed and compared different methods for vegetative propagation of a miniature ornamental pineapple hybrid (ORN-MUT), seeking to determine the best method for production of plantlets, as well as for removal of the PMWaV viral complex from plants cultured in vitro, for production of healthy parent plants. Pineapple wilt is a disease that can cause large economic and is caused by a viral complex called Pineapple mealybug wilt-associated virus (PMWaV). For this, four propagation methods were evaluated (conventional, stem sectioning, micropropagation and etiolation of nodal segments). The time necessary for each method and the number of plants formed were assessed. Stem tips (0.5 mm) were cultured and indexed for three PMWaV types. Conventional propagation produced 17 plantlets per plant in 566 days, stem sectioning produced 2.3 plantlets per stem in 591 days, while the conventional micropropagation technique produced 1,284 plants after four subcultures in 778 days. Stems etiolated for 60 days showed peak production in the second subculture, with 1,224 plants. This method required 883 days to obtain plants with ideal size for transplantation to the field. In turn, stems etiolated for 120 days produced 935 plants at the end of four subcultures, with peak output in the third subculture, in which the plants could be cultivated in the field after 943 days. Conventional micropropagation and etiolation for 60 days were the best methods for production of plantlets of the ORN-MUT hybrid. The results of this work showed that the cultivation of shoot tips is an efficient strategy to remove the PMWaV complex and obtain healthy mother plants and can be a useful tool for other varieties of pineapple.

Establecimiento in vitro de dos especies nativas de Costa Rica: Terminalia amazonia (Amarillón) y Vochysia allenii (Botarrama Blanco) / In vitro establishment of two species native to Costa Rica: Terminalia amazonia (Amarillón) and Vochysia allenii (Botarrama Blanco)

El objetivo de esta investigación fue lograr el establecimiento in vitro de la especie Terminalia amazonia y Vochysia allenii debido a la dificultad de propagarlas sexual y asexualmente con técnicas convencionales. Se logró establecer segmentos nodales de ambas especies en condiciones in vitro empleando el HgCl2 0,1 % con un tiempo de exposición de 5 minutos. El mejor medio de cultivo para nudos fue el WPM 100 % de sales para T.amazonia y para V. allenii fue el WPM 50 % de sales. Después de 28 días de cultivo se obtuvo un 42 % de nudos establecidos para T. amazonia y 10% para V. allenii. En ambas especies se evaluó el efecto sobre la brotación de cinco concentraciones de 6-bencilaminopurina (6-BAP) (0,0; 2.22, 4.44, 6.66, 8.88 μM L-1) y cinco de tidiazuron (TDZ) (0,0; 0.22, 0.45, 0.68, 0.90 μM L-1). Se obtuvó en promedio un brote por explante en los cinco tratamientos de BAP y TDZ utilizados.

The objective of this research was to achieve the in vitro establishment of the species Terminalia amazonia and Vochysia allenii due to the difficulty propagate sexually and asexually with conventional techniques. It was possible to establish the nodal segments of both species in in vitro conditions using 0.1 % HgCl2 with an exposure time of 5 minutes. The best nodal culture medium was 100 % WPM salts in T. amazonia and V. allenii was WPM 50% salts. After 28 days of culture 42 % of nodal segments to T. amazonia and V. allenii 10% was obtained. In both species, the effect on sprouting of five concentrations of 6-benzylaminopurine (6-BAP) (0.0, 2.22, 4.44, 6.66, 8.88 μM L-1) and five thidiazuron (TDZ) (0.0, 0.22, 0.45, 0.68, 0.90 μM L-1) was evaluated. Outbreak was scored on average per explant in the five treatments of BAP and TDZ used.

In vitro Propagation and GC-MS Studies of Ocimum basilicum Linn. var. pilosum (Willd.) Benth.

An in vitro propagation method is outlined for Ocimum basilicum Linn. var. pilosum (Willd.) Benth., a wild aromatic plant belongs to Lamiaceae family. Shoot buds were used as source of explants on MS media supplemented with different concentrations of growth regulators for callus growth, induction of multiple shoots and roots respectively. MS media with 1.5 mg/L of kinetin and 0.5 mg/L of NAA showed 95.5% shooting, maximum number of shoots (7.33) and relatively better shoot lengths (4.15 cm). Excised shoots were carefully transferred to halfstrength MS medium supplemented with 1.0 mg/L indole-3-butyric acid (IBA) for root induction and it yields 86.6% rooting. Whereas, average root length and number of roots observed were 1.73 cm and 3.31 respectively per explants. Rooted plantlets were hardened and successfully established in natural soil, where they grew and matured normally. GC-MS studies in methanolic leaf extract of naturally grown Ocimum species yielded 15 compounds. Two compounds viz. cis-9-Hexadecenal (35.06%) and n-Hexa decanoic acid (21.6%) accounted for the major share (56.66%). On the other hand, 2-hydroxy-6-methylbenzaldehyde (10.99%) as well as 4H-1-Benzopyran-4-one and 5-Hydroxy-6, 7-Dimethoxy-2-(4- Methoxyphenyl) (7.75%) represented only 18.74%. Establishment of reliable in vitro propagation protocol, with phytochemical profile of hitherto unreported Ocimum species further widens the scope to evaluate its therapeutic properties.