Thai Agricultural Research Journal

Development of a Subsoiler with Two Tandem Shanks Arranged for Directional Movement and Automated Depth Adjustment

2024-04-23T12:44:16+07:00

Subsoiling is essential for farmers to rectify soil compaction that reduces crop yields, but it requires high drawbar pull, often exceeding the capabilities of farmers' tractors and increasing costs. This study aimed to develop a tandem-type subsoiler with a front shank equipped with automatic depth adjustment to minimize drawbar pull during subsoiling operations. The front subsoiler shank (FSS) can autonomously adjust its depth, controlled by an automatic depth control system utilizing an Arduino UNO microcontroller. Moreover, the distance between the FSS and the rear subsoiler shank (RSS) is adjustable. Field tests were conducted in Kampheang Sean, Nakhon Pathom, where the soil exhibited a moisture content of 5.4±1.92%, a bulk density of 1.5±0.14 g/cm3, and a soil penetration resistance ranging from 0 to 50 cm depth, with an average of 1.88±0.41 MPa. Four key factors were considered during testing: 1) type of FSS point (winged point and fin point), 2) Motor systems for adjusting the depth of the front subsoiler shank (fixed displacement control system and immediate response system), 3) Motor sensitivity (10, 20 and 30%), and 4) Distance between the FSS and RSS (40, 50 and 60 cm). The subsoiling depth during the test was 50 cm. Results demonstrated that the control system facilitated automatic up and down movement of the FSS to determine the optimal drawbar pull. Specifically, the FSS equipped with a fin point exhibited significantly lower drawbar pull compared to the winged point, with values of 14.84±3.30 kN and 17.66±2.87 kN, respectively. Additionally, a distance of 40 cm between the FSS and RSS resulted in the least drawbar pull of 14.42±3.00 kN. Notably, the tandem-type subsoiler with automatic depth adjustment achieved the lowest drawbar pull of 12.65±1.33 kN, representing a reduction of over 10% compared to a conventional single shank subsoiler, which exhibited a drawbar pull of 14.00±2.01 kN under similar test conditions. Motor systems for adjusting the depth of the front subsoiler shank and sensitivity did not significantly affected drawbar pull. Research results indicate that using a subsoiler with two tandem shanks, where the front shank automatically adjusts its depth, allows farmers to perform subsoiling more efficiently, resulting in better crop yields and reduced costs.

Development of Vertical Planting Mechanism for Sugarcane Transplanter

2024-05-30T08:40:48+07:00

An efficient sugarcane seedling transplanter is essential for transplanting seedlings grown from bud billets to reduce labor cost and planting time The purposes of this research are to create a sugarcane transplanter that the planting mechanism moves vertically using pre-germinated buds and to assess the transplanter's performance. The device that had been developed was a seedling mechanism that used planting funnel attached to a metering disc which received thrust from the soil layer so that the transplanter worked without sending power through the sprockets and chains to the planting mechanism. It was like the planting device itself was the ground wheel, and the planting mechanism was always pressed into the ground to independently plant seedlings into the ground to the desired depth of planting without the use of a soil opener. It was attached to three-point hitches on a 56.7 kW (76 hp) tractor. In this research, the planting distance was controlled by a metering disc, which had a planting funnel mounted on it. Three different diameters: 78 cm (D1), 86 cm (D2) and 96 cm (D3) metering discs were tested in this study. The experimental works were conducted at travel speeds of 1.27, 1.89 and 2.73 km/hr. and planting depths of 10 and 15 cm. Results showed that the average planting pitch of the metering discs D1, D2 and D3 was 36.30, 50.15 and 68.35 cm respectively, and it showed that the planting success rate (PSR) at a 10 cm planting depth was higher than at a 15 cm planting pitch. The success rate of metering disc D3 (67.32%) was higher when compared to metering disc D2 (59.76%) and metering disc D1 (53.18%). These experimental results showed that the planting depth of 10 cm and the forward speed of 1.27 km/hr. were practical operating conditions.

Response of Some Rice Varieties against the Fungus, Exserohilum rostratum, Causing Leaf Spot Disease on Rice and Expression of Plant Hormone Responsive Genes in Rice During Infection

2024-07-12T10:46:02+07:00

Exserohilum rostratum is an ascomycete fungus causing leaf spot on rice and rice seed discoloration in rice-growing areas of several countries. The objectives of this study were to evaluate the response of some rice varieties against E. rostratum and to analyse the expression of plant hormone-responsive genes during infection. Five different rice varieties, Khao Dawk Mali 105 (KDML105), RD31, RD41, Pathum Thani 1, and Jao Hom Nin (JHN) were inoculated with each representative E. rostratum isolate (n=10). Results showed that JHN exhibited the lowest level of disease severity whereas KDML105 displayed the greatest disease severity when infected by E. rostratum. Subsequently, these two varieties were analysed to elucidate their respective defense mechanisms against E. rostratum. Expression of plant hormone-responsive genes, including OsPR1b and OsPBZ1 (salicylic acid-responsive defense genes), JiOsPR10 (jasmonic acid-responsive defense gene), and OsEBP89 (ethylene-responsive gene), were examined with quantitative real-time RT-PCR in KDML105 and JHN inoculated with E. rostratum at 24, 48, and 72 hours. The findings demonstrated that all of the tested genes were upregulated, with the highest levels observed mostly at 24-48 hours after inoculation in both rice varieties, indicating the involvement of these rice genes in response to E. rostratum infection. Indeed, the mechanism of rice resistance to E. rostratum may not be regulated through the jasmonic acid and ethylene signaling pathways. In summary, this study provides information on the potential rice leaf spot resistant variety and fundamental insights contributing to an enhanced comprehension of rice defense mechanisms against E. rostatum.

Insight into Host-driven in Planta Evolution of Columnea Latent Viroid through Quasi-species Population

2024-05-24T09:09:43+07:00

With a high mutation rate and fast replication, a population of mutated viroid progenies is generated and co-exists in the same host plant as a population of variants (so-called quasi-species), showing a huge level of genetic diversity. In our work, we report the evidence of the quasi-species in CLVd in several solanaceous plants; tomato (Rutgers and Seda 50), bolo maka and eggplant. An infectious dsDNA CLVd was synthesized from the recombinant plasmid containing the full-length genome of CLVd isolate Solanum-1 (JF742632) and then inoculated on the plants under specific conditions. The initial inoculation only successfully infected tomato cv. Rutgers. This CLVd-infected Rutgers was used for subsequent inoculation of the above-mentioned host plants. When all host plants proved to be systemically infected, RNA extraction and RT-PCR were performed. To study the CLVd population in individual host plants, the specific CLVd primers linked with an eight base sample-tagging sequence were used for amplifying libraries. The average 20,237 CLVd reads per PCR-replicate and 22 progeny variants in total from the first infected tomato plant were obtained. Among these 22 of CLVd variants, we found 22 total number of single-nucleotide polymorphisms in which average three point-mutations per CLVd genome mainly in Terminal Right and Pathogenic domains were observed. In addition, the estimated mutation rate of CLVd was calculated at 8.15 X10-3. Our data demonstrate that CLVd in a host plant exists as a population of quasi-species while showing host specificity of the dominant variants as host-driven in planta evolution.

Development of SNP Molecular Markers for Detection of Xanthomonas oryzae pv. oryzae Population Causing Bacterial Blight Disease of Rice in Thailand Using MassARRAY Technique

2024-04-30T15:24:50+07:00

Xanthomonas oryzae pv. oryzae (Xoo), the causal organism of bacterial blight, exhibits genetic diversity and adapts continuously to overcome rice varieties with inherent resistance to this disease. To effectively manage bacterial blight, rapid and high-throughput diagnostic tools are essential for monitoring changes in Xoo populations across different regions. In this study, we aimed to develop molecular SNP markers using data from housekeeping gene clusters in Xoo. We analyzed 50 Xoo strains collected during 2008 - 2018 from rice cultivation areas in 14 provinces of Thailand. We designed Xoo-SNPs (single nucleotide polymorphisms) to enable high-throughput multiplex detection based on MassARRAY technology. Our research successfully developed 9 SNP positions derived from eight housekeeping genes (DnaK, gluS, leuA, pyk, pyrH, RecA, rpoB, and tpiA). These markers effectively tracked Xoo populations, representing 33 races prevalent in Thailand, within a remarkable turnaround time of 2 days, excluding the sample preparation step. Furthermore, our approach allowed the simultaneous examination of up to 45 samples per day. Notably, the developed Xoo-SNPs MassARRAY-based markers not only differentiated Xoo strains based on their pathogenicity toward rice varieties carrying the xa5 resistance gene but also identified markers specific to the geographical origin of the strains in provinces such as Nakhon Si Thammarat, Buriram, Roi Et, Sukhothai, and Chiang Rai. However, no significant correlation was observed between the SNP markers designed from housekeeping genes and the race-specific or disease severity characteristics.

Colour and Odour Characteristics of Local Durian Varieties in Songkhla Province

2024-01-30T10:22:08+07:00

The information on colour and odour characteristic of local durian varieties in Thailand are limited. The objective of this research is to investigate the physical and chemical characteristics of 7 local durian varieties from Songkhla province, namely Supnasaen, Phikunklin, Aileuang, Lepyiao, Muktaam, Nomsao, and Nomsod. The study utilized scientific instruments to collect data that could serve as a basis for promoting and selecting durian varieties in the future. The flesh of all seven varieties was analyzed for color using a colorimeter, elemental composition using a CHNS/O analyzer and volatile organic compounds (VOCs) using headspace solid-phase microextraction (HS-SPME) followed by GC-MS analysis. Yellow index values were found to effectively and rapidly indicate the initial differences between each durian variety. In terms of elemental composition, the highest carbon and hydrogen content were found in Supnasan (44.42±0.20 and 7.04±0.04%, respectively), the highest nitrogen and sulfur content in Nomsao (1.49±0.02 and 0.11±0.01%, respectively), and the highest oxygen content in Aileuang (48.12±0.22%). The results of the odour analysis revealed a total of 52-74 volatile organic compounds (VOCs) which categorized into 18 functional groups. Specific compounds were unique to certain varieties such as; Aldehyde was found only in the Aileuang variety, Azine was found only in the Muktaam variety, Diene was found in the Supnasaen and Lepyiao varieties, Ether was found in the Nomsao and Nomsod varieties, Oxazole was found in the Muktaam and Nomsao varieties. Thiazole was found in the Aileuang and Lepyiao varieties, Pyrazine was found, but volatile sulfur was not found in the Phikunklin variety, Carboxylic acid was not found in the Lepyiao variety and Terpene was not found in both the Supnasaen and Nomsao varieties. Esters and sulfides were the main functional groups providing odour across all varieties, but in varying quantities. Results of this research demonstrated methods of physical and chemical analyses that can be used to promote the cultivation of durian varieties with colour and odour profiles preferred by consumers.

Effects of Fruit Bagging Materials on Yield and Fruit Quality of ‘Barhee’ Date Palm

2024-07-08T12:47:30+07:00

Fruit bagging is an important factor for increasing the quality of date palm yield. This experiment was conducted to investigate the effects of fruit bagging materials on yield and fruit quality of date palm variety “Barhee” at farmer's orchard in Fang district, Chiang Mai province in 2023. The experiment used randomized complete block design with five replications. Four treatments were investigated: 1) non- bagging, 2) transparent plastic bag, 3) blue plastic bag and 4) brown paper bag. Date palm fruits were thinned and covered with three different bags at the age of 2 months after pollination. The fruit samples were investigated for physical and quality changes. We found that using blue plastic bag or brown paper bag or transparent plastic bag resulted in larger fruit size, weighing 14.03-15.49 g, seed length 22.04-22.19 mm, seed weight 1.30-1.35 g, bunch weight 7.45-8.72 kg, number of fruits per bunch 561.5-676.5 and pulp weight 12.70-14.14 g which were significantly higher than non-bagging treatment with fruit weight 11.97 g, seed length 20.45 mm, seed weight 1.21 g, bunch weight 1.1 kg, number of fruits per bunch 74.33 and pulp weight 10.76 g. Bagging with blue plastic bag or brown paper bag or transparent plastic bag could similarly decrease damages caused by disease, insects, fruit cracking and birds better than non-bagging. Moreover, blue plastic bag and brown paper bag also improved peel color to dark yellow throughout bunch and extended harvesting period which were better than transparent plastic bag and non-bagging. There were no differences in TSS and brown seed coloration between bagging or non-bagging. Overall, blue plastic bag was recommended for Barhee date palm fruit bagging because this treatment could improve fruit quality, reduce fruit damage, extend harvesting period and be economical than other bagging treatments.

Yield Trial of Pisang Mas Banana Mutant Clones Derived from Gamma Irradiation

2024-07-11T14:41:00+07:00

Growing Pisang Mas banana varieties that are suitable for each area is one of the methods to increase yield and quality. The objectives of this experiment were to compare and select Pisang Mas banana mutant clones derived from Gamma irradiation for high yield and quality suitable for commercial production in southern Thailand. The experiment was conducted at Trang Horticultural Research Center in Trang province from October 2018 to September 2020. A completely randomized design of six treatments with three replicates comprised 5 Pisang Mas banana mutant clones, KM8-22, KM9-20, KM22-5, KM22-27, KM30-11 and Kamphaeng Phet (commercial variety) was used. Results showed that KM22-27, KM30-11 and Kamphaeng Phet gave closely and consistently higher yield than the others in two consecutive harvesting seasons. The yield range in the first, second year and average of two years were between 3,909-4,180, 3,989-4,248 and 3,980-4,149 kg/rai, respectively. For quality, KM22-27 and KM30-11 had statistically significant less sour taste than that of Kamphaeng Phet. In addition, the yield components of KM22-27 and KM30-11, i.e., bunch weight, panicle weight, fruit weight and fruit length had no statistical differences compared to those of Kamphaeng Phet. Therefore, KM22-27 and KM30-11 were the two new Pisang Mas banana clones which had potential for commercial production in Trang province or the southern region of Thailand in the future.

Comparison in Fresh Fruit Bunch Yield of Five Oil Palm Hybrids and Two commercial Oil Palms at the Young Mature Phase

2024-07-16T09:06:33+07:00

The young mature phase is a pivotal period for small oil palm plantations, as bunch harvesting takes about 2-3 years. Our study aimed to evaluate the bunch yields of five hybrids (H1–H5) and two commercial Tenera oil palms during this crucial phase. The assessment, conducted over four consecutive years from 2012 to 2015 at the Hong Sila Agriculture and Industry Company Limited, Krabi, Thailand, revealed some intriguing findings using a randomized complete block design with four replicates spaced 9 meters in a triangular pattern. H3 emerged as the best Tenera, delivering the highest fresh fruit bunch (FFB, 243.90 kg/palm/year) over other hybrids and two commercial varieties. H4 demonstrated the highest bunch number (BNO, 26.04 bunches/palm/year) and the lowest average bunch weight (ABW, 8.17 kg/bunch) in the young mature phase. The H3 and H5 were high FFB over checks varieties followed by year. This information was essential in selecting oil palm parents, which had high potential for crossing to produce new hybrids and recognize to choose for their genetics to improve oil palm variety. These findings highlighted the potential benefits of understanding the impact of genetics on the parents of oil palm to produce Tenera.