In vitro propagation of a rare orchid, Bulbophyllum nipondhii was carried out. Five different media were tested to find the suitable medium for seed germination and seedling development. The tangible results were obtained on VW medium. To assess the effect of pollination types on seed germination and seedlings development, seeds derived from different self‐, cross‐ and open‐pollination were examined. Open‐pollinated seeds produced the best germination and the highest seedling development, followed by cross‐ and self‐ pollination. VW medium was supplemented with 0, 25, 50 or 75 g/l potato extract (PE) and 0, 50, 100, 150 or 200 ml/l coconut water (CW) to identify their most suitable concentration. PE (75 g/l) with 100 ml/l CW was found to be best combination. Plant Tissue Cult. & Biotech. 26(1): 37-46, 2016 (June)

Epipactis flava Seidenf. is an endangered Thai rheophytic orchid that has recently shown a rapid decrease in its natural habitat, prompting an urgent need for conservation using ex situ reintroduction methods. Temporary immersion system (TIS) has been successfully applied for large-scale propagation in various plants species. Propagation efficiency of E. flava using TIS was investigated and compared with conventional semi-solid system (SSS) and liquid continuous immersion system (CIS). The highest percentage of new shoot and shoot bud formation was obtained from TIS, followed by CIS and SSS, respectively. Growth parameters as indicated by number of new shoots, shoot buds, shoot height and leaves per explant were significantly higher using TIS than with SSS and CIS. Moreover, the maximum number of new shoots and shoot buds per replication were reliably obtained from TIS higher than SSS and CIS. After acclimatization, the highest survival percentage of plantlets was observed in TIS (76.7%), with 60% surviving after eight weeks of transplantation in artificial stream. TIS was determined as the most suitable culture system for in vitro mass propagation of E. flava compared to CIS and SSS.

Natural herbicide is considered as a sustainable approach for weed management in agriculture. Here, allelopathic activities of Piper betle L. extract (BE) and known allelochemical eugenol (EU) were studied against rice and associated weeds in terms of germination and seedling growth. Five plant species including a rice crop (Oryza sativa L.); a dicot weed, false daisy (Eclipta prostrata (L.) L.); and three monocot weeds, barnyard grass (Echinochloa crus-galli (L.) P. Beauv.), swollen fingergrass (Chloris barbata Sw.), and weedy rice (Oryza sativa f. spontanea Roshev.) were studied. The paper-based results demonstrated that BE and EU had inhibitory effects on seed germination and seedling growth. The IC₅₀ values of BE and EU for seed germination were ranked from swollen fingergrass, to false daisy, barnyard grass, rice, and weedy rice, respectively. The ratio of root to shoot length of the seedlings indicated that the roots were more affected by the treatments than the shoots. In addition, the gel-based results showed the reduction of the rice seedling root system, especially on lateral root length and the numbers upon the treatments. Taken together, BE had an allelopathic activity similar to that of EU. Interestingly, the major paddy weed, barnyard grass, was more sensitive to BE than rice, underlining BE as a natural herbicide in rice agriculture.

Musa (ABB) ‘Mali-Ong’ is an economically important banana cultivar in Thailand. We morphologically and molecularly characterized ‘Nam Wa Mali-Ong’. Leaf blade width was the only statistically different morphological character among the clones. To determine genetic variation, nine ‘Nam Wa Mali-Ong’ clones were compared with 10 samples of Musa ABB, AA, and BB cultivars by fingerprinting using seven pairs of sequence-related amplified polymorphism (SRAP) and eight inter simple sequence repeat (ISSR) markers. The SRAP and ISSR primers generated 65 and 76 amplicons, respectively, of which 57 (87.7%) and 62 (81.6%) amplicons, respectively, were polymorphic; the polymorphic information content was 0.28–0.49. The SRAP data revealed two distinct groups: Group I, comprising two subgroups (one including all ABB samples and the other containing the BB genome accessions), and Group II, comprising the AA genome accessions. The ISSR data revealed two groups: Group I, which incorporated the AA (Hom Champa) genome, and Group II, consisting of two subgroups: Subgroup A, comprising only the AA (Hom Chan) accessions, and subgroup B, comprising all the ABB accessions and wild banana M. balbisiana (BB genome). The ‘Nam Wa Mali-Ong’ samples clustered together, regardless of the markers used. SRAP and ISSR markers will be useful for germplasm evaluation and future Musa (ABB) improvements.