Conservation and Utilization of Crop Genetic Resources in Malaysia： Mardi＇s Effort

Malaysian Agriculture Research and Development Institute （MARDI） is the country＇s major custodian of the nation＇s crops genetic resources. It has a global responsibility in the conservation of genetic resources of banana, sweet potato and citrus, and national responsibility for the conservation of crops, such as rice, tropical fruits and some herbs and medicinal plant species. MARDI rice seed genebank at Seberang Prai in the state of Penang was established in 1984 and currently holds 12,770 registered rice accessions, of which 53% are of local origin. In addition, MARDI also conserves genes in the field, mostly for underutilized tropical fruit genetic resources. At present, about 168 species of underutilized, rare and wild tropical fruit species consisting of about 2,000 accessions, the largest in the country, are being conserved. The species include ＂kuini＂ （Mangifera odorata）, ＂bacang＂ （Mangifera foetida）, ＂binjai＂ （Mangifera caesia）, ＂cerapu＂ （ Garcinia praniana）, ＂rambai＂ （Baccaurea motleyana）, ＂asam gelugor＂ （ Garcinia atroviridis）, ＂terap＂ （drthocarpus odoratissimus） and ＂pulasan＂ （Nephellium rambutan-ake）. The accessions are mostly conserved ex situ in field genebanks located at the various MARDI stations throughout the country. Although the conservation of the various crop species genetic resources is important, the real challenge is enhancing its utilisation. The main objective of the paper was to share and disseminate information related to works conducted and strategies opted by MARDI on the conservation and utilization of crop genetic resources. Information on species of crops that are available in MARDI＇s genebank was also highlighted together with brief information of some of the associated traits of significant importance posses by those genetic resources.

<i>In Vitro</i>Micropropagation of a Valuable Medicinal Plant, <i>Plectranthus amboinicus</i>

The effect of the plant growth regulators benzyl amino purine (BAP), 1-naphthaleneacetic acid (NAA) and kinetin (KIN) on in vitro shoot induction and proliferation of Plectranthus amboinicus was examined. Explants obtained from lateral shoots and apical shoots of P. amboinicus were inoculated on Murashige and Skoog (MS) culture medium supplemented with different concentrations of BAP, NAA and KIN. When the effect of each growth regulator was considered singly, the highest rate of shoot induction (80% of explants producing shoots) and highest number of shoots produced (2.4 shoots per explant) were obtained from lateral shoot explants cultured on MS media supplemented with 3.0 mg/L BAP within 6 - 7 weeks. Better results were obtained using MS medium supplemented with 1 mg/L BAP + 5 mg/L NAA. Shoot proliferation rose to 85%, while 5.7 shoots per explants were recorded. Among the different media tested for rooting, MS medium supplemented with 1.0 mg/L IBA was the most effective for root induction. The quality of the roots obtained was better than that obtained using MS media supplemented with NAA or IAA.

Comparative Leaves Anatomical Studies of Bouea, Mangifera and Spondias （Anacardiaceae） in Malaysia

Leaves anatomy of two species of Bouea, 11 species of Mangifera and two species of Spondias were studied in order to see the differences in stomata type, petiole, midrib and lamina anatomy and leaf venation. This study aims to use anatomical characters for species and genus identification. Common characters observed were the absence of trichomes, closed vascular bundles, uniseriate epidermal layers, resin canal in parenchyma cells, anticline wall pattems and druses crystals in leaf lamina transverse sections. All species displayed closed vascular bundles except Mangiferapajang which showed a combination of medullary vascular bundles. Uniseriate epidermal layer was observed in all species. All the species showed straight-wavy anticlinal walls. Druses crystals were found in the parenchyma cells of all the species. Four types of stomata were observed namely anomocytic, anisocytic, staurocytic and diacytic. Anomocytic, anisocytic and staurocytic stomata were observed in Mangifera, diacytic in Bouea and anomocytic in Spondias.