Wichcha Journal Nakhon Si Thammarat Rajabhat University

Genetic Diversity of Cocoa Varieties in Nakhon Si Thammarat Province Assessed by AFLP Markers

Kedsirin Ruttajorn — 2026-02-05

The genetic diversity of Theobroma cacao L. was investigated using amplified fragment length polymorphism (AFLP) markers. DNA was analyzed from six cocoa samples: two known varieties (Pa7 × Na32 and UIT1 × Na32) obtained from the Chumphon Horticultural Research Centre and four farmer-grown trees (C-4, C-6, C-8, and C-9) collected from Nakhon Si Thammarat Province. Three primer combinations (E-AAC/M-CTC, E-AAG/M-CTA, and E-AAC/M-CTA) yielded an average of 4.67 polymorphic bands per combination, with E-AAC/M-CTC producing the highest number of polymorphic bands (9). The mean polymorphism information content (PIC) value was 0.32, and E-AAG/M-CTA exhibited the highest PIC value (0.37), indicating that it was the most informative primer combination for genetic diversity assessment in this study. Cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA) separated the samples into two major clusters, with the second cluster serving as an outgroup. Within Cluster I, two subclusters were identified, revealing close genetic relationships between farmer-grown trees and the known varieties. The findings provide useful information for identifying genetic origins of local cocoa and support appropriate selection for propagation and processing in Nakhon Si Thammarat Province.

Properties of Reclaimed Asphalt Pavement (RAP) Stabilized with Crushed Rock and Stone Dust

Khemaporn Khan-ngern — 2026-02-13

This research investigated the properties of reclaimed asphalt pavement (RAP) stabilized with crushed rock and stone dust for use as an alternative pavement material. Crushed rock and stone dust were employed as stabilizing additives to enhance the compressive strength of RAP. Both additives were first subjected to gradation analysis, and materials meeting the specification were selected for mix design. Pavement in-place recycling mixtures were designed in accordance with the Thai Department of Highways standard DH-S 213/2543 for reclaimed asphalt pavement (RAP). The mixtures were prepared by combining RAP with two types of additives crushed rock and stone dust at three RAP-to-additive ratios of 25:75, 50:50, and 75:25 by weight. Unconfined compressive strength tests were conducted on the prepared mixtures. The results indicated that stabilized RAP has potential for use as an alternative material in road construction and rehabilitation. In particular, the mixture with a RAP-to-additive ratio of 25:75 satisfied the Department of Highways requirement for a cement-treated gravel subbase layer, achieving a minimum unconfined compressive strength of 24.50 kgf/cm² (ksc) after 7 days of curing.

Effects of Bamboo Soil and Organic Fertilizer on the Growth and Yield of Dictyophora indusiata Grown in Pots

Komgrit Saeng-ngoen — 2026-02-09

This research aimed to evaluate the effects of bamboo soil and organic fertilizer on the growth and yield of Dictyophora indusiata (bamboo mushroom) cultivated in pots. Mushrooms were cultivated in 15-inch pots containing a substrate of bamboo chips, bamboo leaves, and sucrose, amended with five ratios of bamboo soil to organic fertilizer (100:0, 75:25, 50:50, 25:75, and 0:100, w/w). The experiment was arranged in a Randomized Complete Block Design (RCBD) with six replications per treatment. The results showed that the mycelium colonized all substrate ratios within 30 days after inoculation. The substrate with a 0:100 ratio (100% organic fertilizer) induced the fastest fruiting body initiation (pinhead stage) at 38 days after inoculation (p < 0.05). In contrast, the 75:25 w/w ratio resulted in the shortest development period from pinhead to mature stage (14 days) and produced the highest number of fruiting bodies (18.17), but also the highest number of aborted fruiting bodies (12.00) (p < 0.05). Furthermore, the 75:25 w/w ratio yielded fruiting bodies with the greatest fresh weight (58.90 g), stipe length (17.07 cm), stipe diameter (2.73 cm), and veil length (20.10 cm) (p < 0.05). For mushrooms harvested at the egg stage for gel collection, the 100:0 w/w ratio produced the largest egg size (4.78 cm in diameter) (p < 0.05) and the highest gel yield (17.00 g).

Effect of Paclobutrazol on the Slow Growth of Momordica cochinchinensis (Lour.) Spreng In Vitro

Sainiya Samala — 2026-02-05

The effect of paclobutrazol (PBZ) on slow-growth storage of Momordica cochinchinensis (Lour.) Spreng. was studied in vitro. Apical shoots were cultured on Murashige and Skoog (MS) medium supplemented with PBZ at concentrations of 0, 1, 2, and 4 mg/L and maintained at 25±2 °C under a 14-h photoperiod. The results revealed that PBZ caused a significant decrease in shoot height and in the number of leaves per plantlet. MS medium supplemented with 4 mg/L PBZ resulted in the lowest average shoot height (2.18 cm) and average leaf number (5.2 leaves per plantlet), which were significantly different from those on the medium without PBZ (3.20 cm and 6.4 leaves per plantlet, respectively). After three months of culture on PBZ-containing medium, shoots were transferred to root induction medium (MS medium with 1 mg/L IBA). Shoots derived from medium with 4 mg/L PBZ exhibited an average shoot height of 2.20 cm and an average root length of 0.86 cm, which were significantly different from the values for shoots cultured without PBZ (2.76 cm and 3.38 cm, respectively). Therefore, supplementation of the culture medium with 4 mg/L PBZ was the most effective treatment for inducing slow growth and for the in vitro preservation of M. cochinchinensis.

Study on the Optimal Factors for Briquetting Charcoal from Coconut Shells Using a Full Factorial Experimental Design

Yossawat Cheewaworanontree — 2026-02-05

This research aimed to investigate the optimal factors for compressing coconut shell charcoal briquettes using a full factorial design (2^k full factorial design). A coconut shell charcoal briquette compressing machine was developed with a width of 60 cm, a length of 66 cm, and a height of 149 cm. The machine employed a semi-automatic power transmission system driven by a 7.5-horsepower electric motor (380 V), equipped with a 3.5-inch drive pulley and a 21-inch driven pulley. The experimental design consisted of three factors: screw length (30-32 cm), compression cylinder size (45-47 mm), and motor speed (254-267 rpm). The experiment was repeated three times with 30 samples per trial, resulting in a total of 24 experimental runs. The results indicated that the optimal conditions for briquette compression were a screw length of 30 cm, a compression cylinder size of 45 mm, and a motor speed of 254 rpm. These optimal factors were subsequently applied in an additional experiment to collect comparative data. The results showed that, prior to optimization, 19 briquettes (21.10%) were broken or insufficiently compacted, whereas after optimization the number decreased to 8 briquettes (8.90%), representing a reduction of 11 briquettes (57.89%).

Effect of Planting Materials and Chemical Fertilizers on the Growth and Yield of Clitoria ternatea L.

Anan Piriyaphattarakit — 2026-02-05

This study aimed to investigate the effects of planting media and chemical fertilizer on the growth and flower yield of Clitoria ternatea L. The experiment was arranged in a randomized complete block design (RCBD) consisting of two separate experiments. 1) The first experiment evaluated five planting media formulas: (1) soil mixed with Samanea saman leaf compost (control), (2) peat moss : soil mixed with S. saman leaf compost (1:1), (3) peat moss : perlite : soil mixed with S. saman leaf compost (1:1:1), (4) peat moss : perlite : soil mixed with S. saman leaf compost (1:2:1), and (5) soil mixed with S. saman leaf compost : chopped coconut husk (1:1). 2) The second experiment examined the effects of chemical fertilizer (16-16-16) applied at rates of 0, 10, 15, 20, and 25 g per plant. Plants were grown in 20-inch pots. Vegetative growth was recorded every 15 days after transplanting for two months, while flower yield was evaluated over a six-month period. The results showed that planting media significantly affected plant growth and flower yield. Plants grown in planting medium formula 3 exhibited the greatest plant height (170.00 cm), the highest number of flowers (139 flowers per plant), and the highest fresh and dry flower weights (52.32 and 5.83 g, respectively). Regarding fertilizer application, the rate of 10 g per plant resulted in the highest number of shoots (43 shoots per plant) and the largest stem diameter (0.78 cm). In contrast, fertilizer application at 15 g per plant produced the highest fresh and dry flower weights (80.65 and 8.03 g, respectively). Therefore, planting medium formula 3 combined with chemical fertilizer at a rate of 10 g per plant was considered the most suitable treatment for promoting optimal growth and flower yield of C. ternatea L.

Effects of Operating Modes and Electric Potential Difference on Image Quality and Elemental Analysis of Zinc Oxide Nanomaterials

Nidcha Aroonrote — 2026-02-09

This research focuses on selecting the optimal operating mode and accelerating voltage for the analysis of zinc oxide (ZnO) nanomaterials using a Field Emission Scanning Electron Microscope (FESEM) combined with Energy Dispersive X-ray Spectroscopy (EDS). The effects of operating mode and accelerating voltage on image quality and elemental analysis were evaluated. The results showed that the GB-HIGH mode at an accelerating voltage of 2 kV produced the sharpest images and revealed the most detailed surface morphology compared with the SEM mode and other accelerating voltages. In addition, EDS analysis indicated a uniform distribution of zinc (Zn) and oxygen (O) on the material surface. A comparison between the Analyzer method and the Point & ID method for elemental quantification revealed similar Zn and O contents, consistent with the characteristics of ZnO nanomaterials. These results highlight the importance of selecting appropriate operating parameters to enhance image quality and improve the accuracy of elemental analysis in nanomaterial research, and they can be applied to future materials research and development.

Effects of Salt-Farm Residue Application Rate on Fruit Quality of ‘Hom Thong’ Banana

Boonchart Kativat — 2026-02-09

This study investigated the use of salt-farm residue to improve the fruit quality of ‘Hom Thong’ banana. The experiment consisted of five treatments: (1) control (no fertilizer), (2) chemical fertilizer 13-13-21 at 125 g per plant, (3) salt-farm residue at 240 g per plant, (4) salt-farm residue at 480 g per plant, and (5) salt-farm residue at 720 g per plant. The results showed that fertilizer 13-13-21 produced the greatest fruit width, fruit length, bunch weight, and fruit weight. The application of salt-farm residue at 720 g per plant resulted in the lowest firmness values for mature-green and ripe fruits (4.88±0.34 and 0.338±0.016 N, respectively). Salt-farm residue at 480 and 720 g per plant produced the highest total soluble solids (TSS) in ripe fruits (21.37±0.88 and 21.51±0.77 °Brix, respectively). In addition, salt-farm residue at 720 g per plant resulted in a TSS/TA ratio of 36.52±5.16. Overall, the highest application rate of salt-farm residue improved fruit quality, particularly by increasing TSS. Further studies should investigate higher application rates or the combined use of salt-farm residue with chemical fertilizer to reduce production costs and improve product quality.

Diversity and Nutritional Value of Local Vegetable Side Dishes (Pak Nhor) in Muang Khon–Style Thai Rice Noodle Meals within the Kao–Pa–Na–Lay Context of Nakhon Si Thammarat

Chantira Wongwichian — 2026-02-06

This study aimed to investigate the diversity and nutritional value of processed local vegetable side dishes (Pak Nhor) served with Khanom Jeen (Thai rice noodles) in four distinct geographical contexts mountain (Kao), forest (Pa), rice field (Na), and coastal (Lay) areas of Nakhon Si Thammarat Province, Thailand. Data were collected through field interviews and laboratory-based nutritional analyses. The results indicated that processed Pak Nhor could be classified into three main categories: pickled vegetables, coconut-blanched vegetables, and traditional salad-type preparations. Pickled cucumber, pickled papaya, and coconut-blanched vegetables were commonly found across all four areas. Traditional salad-type preparations were found exclusively in the rice field (Na) area, including young mango salad and young mango salad with local freshwater crab (Pu Piaw). Distinctive processed vegetables in the mountain (Kao) area included pickled Luk Pra (local wild legume pods) and pickled bitter bean (Sator). The coastal (Lay) area featured pickled mustard greens and a coconut-blanched mixed vegetable dish locally known as “Four Friends,” while the forest (Pa) area was characterized by Ajaad-style pickled cucumber and a coconut-blanched mixture of water spinach and banana stalks. Nutritional analysis revealed that different types of processed Pak Nhor exhibited distinct nutrient profiles. Pickled vegetables generally contained higher sodium and sugar contents. Pickled nipa palm fruit, pickled banana pith, and pickled cucumber showed high sugar contents (15.09±0.04, 11.20±0.03, and 9.74±0.04 g per 100 g edible portion, respectively). In contrast, pickled Luk Pra, pickled Sator, and pickled mustard greens were high in sodium (1,256.70±0.57, 1,102.40±0.25, and 829.40±0.06 mg per 100 g edible portion, respectively). In addition, each type of processed vegetable demonstrated distinctive vitamin and mineral contents depending on the plant species and processing method used. This study highlights the potential of processed local vegetables (Pak Nhor) as traditional functional foods that contribute to dietary diversity, support local food systems, promote community-based economic development, and aid in the preservation of regional culinary heritage.

Focal Mechanisms from Waveform Inversion and Multiple Velocity Models: Phayao Fault Zone, Northern Thailand

Kasemsak Saetang — 2026-02-13

Northern Thailand, situated within the complex Sunda Tectonic Plate, shows significant seismic activity due to its proximity to major tectonic boundaries; however, it often has lower to medium magnitudes. One of the delineated active fault zones is the Phayao Fault Zone (PFZ), which generated an M_w 6.3 earthquake in 2014. Its further south located Pan Segment is also active, but with lower magnitudes. However, understanding and characterizing its seismicity is essential for ongoing seismic hazard assessment of the area. To overcome the challenges, waveform inversion techniques in combination with multiple velocity models were employed, with the aim to characterize the seismic source parameters of earthquakes in this area. Hypocentres were determined with exceptional precision and subsequently validated by applying a velocity model that demonstrated the highest double-couple percentage. This indicates the model's efficacy in precisely calculating hypocentral parameters in this specific geological context. Our findings unveil a complex interplay between right-lateral strike-slip and reverse faulting mechanisms, consistent with a transpressional tectonic regime in the Pan Segment. This regime reflects the accommodation of regional compressional stresses superimposed on the dominant strike-slip motion along the Phayao Fault Zone, thereby yielding a significant contribution to seismic hazard assessment in Northern Thailand. The study also underscores the need for further research to refine these models and methodologies, thereby enhancing our understanding of the seismic characteristics of earthquakes in such regions. Methodologies and insights gained here could serve as a model for characterizing seismic source parameters in other understudied low-seismicity regions globally.