Cryopreservation of Protocorm-Like Bodies of Orchid Hybrid Dendrobium Kasem Boonchoo White by Vitrification

The present study was conducted to develop a protocol for long-term preservation of orchid germplasm. Protocorm-like bodies (PLBs) of orchid hybrid Dendrobium Kasem Boonchoo White were subjected to different treatments of preculture, cryoprotection and dehydration procedures of vitrification technique. The PLBs were precultured on Vacin and Went medium supplemented with 0, 0.06,0.1,0.3,0.5 and 0.7 M sucrose for 3 days. Preculturing with 0.06 to 0.5 M sucrose gave 3.7 to 23.3% viability after cryopreservation. No viable PLBs were found from 0 and 0.7 M sucrose treatments. None of the PLBs survived cryopreservation in all the sucrose concentrations tested. The PLBs were precultured with 0.3 M sucrose for 0, 1, 3, 5, 7 and 9 days. Viability ranged from 11.1 to 26.3% after cryopreservation from 1 to 9 days treatments. No viability was recorded after cryopreservation from treatment without sucrose preculture. There was no survival recorded in all treatments after cryopreservation. When precultured PLBs were cryoprotected with different loading solutions (LSI, LS2, LS3, LS4, LS5 and LS6) for 15 min, all treatments gave 7.4 to 34.4% viability after cryopreservation. All treatments gave 3.7 to 11.1% survival after cryopreservation except LS 1 and LS2 treatments. PLBs were cryoprotected with LS5 for 0, 5, 10, 15, 20, 25 and 30 min. Viability of 7.4 to 36.8% were recorded after cryopreservation when cryoprotected for 5 to 30 min. Without cryoprotection, viability was zero after cryopreservation. The survival rates of 11.1 to 30.3% were obtained after cryopreservation from 5 to 25 min treatments. Cryoprotection for 30 min and without cryoprotection did not give any survival at all after cryopreservation. Cryoprotected PLBs were dehydrated with different vitrification solutions (VS 1, VS2, VS3, VS4 and VS5) for 10 min. All vitrification solutions gave 11.1 to 39.2% viability after cryopreservation. Survival of 7.4 to 26.3% after cryopreservation were recorded in all treatments except VS 1

Influence of soil chemical properties on relative abundance of arbuscular mycorrhiza in forested soils in Malaysia

Th eeff ect of soil chemical properties on the diversity and colonization of arbuscular mycorrhiza (AM) varies among ecosystems. This study was conducted to assess and compare the abundance of AM in a rehabilitated forest and a logged-over forest soil using the most probable number and spore number methods. Glomus (71.7%-82.1%) and Acaulospora (17.4%-19.5%) were found to be abundant in both sites, while Gigaspora was found only in the loggedover forest. Th e abundance of AM in the rehabilitated forest based on the spore count was signifi cantly higher than in the logged-over forest by a 6-fold diff erence. Furthermore, root colonization in the rehabilitated forest was found to be almost 9-fold higher than in the logged-over forest. Such diff erences are linked to the soil chemical properties. The addition of organic matter during forest rehabilitation activity had created favorable conditions for AM sporulation. Soil P in both forests was positively related to the spore count (r > 0.68, P < 0.001) while the most probable number (MPN)was negatively infl uenced by soil K (r = –0.632, P <0.01). In conclusion, this study showed that soil chemical properties have a direct eff ect on the abundance of AM

Tissue Culture and Cryopreservation of Banana {Musa spp.)

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Genetic improvement of banana using conventional and in vitro technologies.

Banana (Musa spp.) is an important nutrient-rich fruit crop cultivated in the tropics and sub-tropics for local consumption and export. Targets for genetic improvement of banana range from improved fruit quality, yield, disease resistance, tolerance to biotic and abiotic stresses, and the biosynthesis of pharmaceutical compounds. Sterility has limited the success of generating new cultivars by conventional breeding. Tissue culture-based technologies that involve embryo rescue, the generation of somaclonal variation, and gene-transfer procedures are a useful adjunct to sexual hybridization, although considerable effort is required to establish robust protoplast-to-plant systems for somatic hybridization. Transformation involving Agrobacterium and biolistics- mediated gene transfer is feasible, underpinned by shoot regeneration from cultured cells and tissues. Molecular characterization of germplasm will facilitate the selection of material most relevant for incorporation into sexual and somatic genetic-improvement programs