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Rhizobacteria are well recognized for their beneficial multifunctions as key promoters of plant development, suppressing pathogens, and improving soil health. In this study, experiments focused on characterizing the plant growth promotion (PGP) and extracellular hydrolase production traits of rhizobacteria, and their impact on Jerusalem artichoke growth. A total of 50 isolates proved capable of either direct PGP or hydrolase-producing traits. Two promising strains (Enterobactercloacae S81 and Pseudomonasazotoformans C2-114) showed potential on phosphate and potassium solubilization, IAA production, and 1-aminocyclopropane-1-carboxylic acid deaminase activity and hydrolase production. A hydrolase-producing strain (Bacillussubtilis S42) was able to generate cellulase, protease, amylase, β-glucosidase, and phosphatase. These three selected strains also gave positive results for indirect PGP traits such as siderophore, ammonia, oxalate oxidase, polyamine, exopolysaccharide, biofilm, motility, and tolerance to salinity and drought stress. Colonization was observed using a scanning electron microscope and rhizobacteria appeared at the root surface. Interestingly, inoculation with consortia strains (S42, S81, and C2-114) significantly increased all plant parameters, including height, biomass, root (length, surface, diameter, and volume), and tuber fresh weight. Therefore, we recommend that potential consortia of PGP and hydrolase-producing rhizobacteria be employed as a biofertilizer to improve soil and boost crop productivity.

Stem rot is a serious disease in Jerusalem artichoke (JA). To reduce the impact of this disease on yield and quality farmers often use fungicides, but this control method can be expensive and leave chemical residues. The objective of this study was to evaluate the efficacy of two biological control agents, Trichoderma harzianum T9 and Bacillus firmus BSR032 for control of Sclerotium rolfsii under field conditions. Four accessions of JA (HEL246, HEL65, JA47, and JA12) were treated or notreated with T. harzianum T9 and B. firmus BSR032 in a 4 × 2 × 2 factorial experiment in two fields (environments), one unfertilized and one fertilized. Plants were inoculated with S. rolfsii and disease was evaluated at 3-day intervals for 46 days. T. harzianum T9 and B. firmus BSR032 reduced disease incidence by 48% and 49%, respectively, whereas T. harzianum T9 + B. firmus BSR032 reduced disease incidence by 37%. The efficacy of T. harzianum T9 and B. firmus BSR032 for control of S. rolfsii was dependent on environments and genotypes. The expression of host plant resistance also depended on the environment. However, HEL246 showed consistently low disease incidence and severity index in both environments (fertilized and unfertilized). Individually, T. harzianum T9, B. firmus BSR032, or host plant resistance control stem rot caused by S. rolfsii in JA. However, no combination of these treatments provided more effective control than each alone.

Due to different functions of phosphate solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF), their potential synergistic effects on enhancing plant growth and yield are worth investigating, especially under adverse conditions. This work focused on the isolation of PSB and characterization for their plant growth promoting properties under drought. The most efficient P solubilizing bacterium was isolated and identified as

Drought is more concerned to be a huge problem for agriculture as it affects plant growth and yield. Endophytic bacteria act as plant growth promoting bacteria that have roles for improving plant growth under stress conditions. The properties of four strains of endophytic bacteria were determined under water deficit medium with 20% polyethylene glycol. Bacillus aquimaris strain 3.13 showed high 1-aminocyclopropane-1-carboxylate (ACC) deaminase production; Micrococcus luteus strain 4.43 produced indole acetic acid (IAA). Exopolysaccharide production was high in Bacillus methylotrophicus strain 5.18 while Bacillus sp. strain 5.2 did not show major properties for drought response. Inoculation of endophytic bacteria into plants, strain 3.13 and 4.43 increased height, shoot and root weight, root length, root diameter, root volume, root area and root surface of Jerusalem artichoke grown under water limitation, clearly shown in water supply at 1/3 of available water. These increases were caused by bacteria ACC deaminase and IAA production; moreover, strain 4.43 boosted leaf area and chlorophyll levels, leading to increased photosynthesis under drought at 60 days of planting. The harvest index was high in the treatment with strain 4.43 and 3.13 under 1/3 of available water, promoting tuber numbers and tuber weight. Inulin content was unchanged in the control between well-watered and drought conditions. In comparison, inulin levels were higher in the endophytic bacteria treatment under both conditions, although yields dipped under drought. Thus, the endophytic bacteria promoted in plant growth and yield under drought; they had outstanding function in the enhancement of inulin content under wellwatered condition.

Most Jerusalem artichoke (JA, Helianthus tuberosus L.) grown as edible functional food plant, produce more tubers with high stems (1.5-2.0 m). To develop them as potted plant it is necessary to control their height and to increase branches in order to create a more compact canopy. Two experiments were conducted under greenhouse conditions. Experiment 1 demonstrated that pinching seedlings at all position (2, 3, and 4 leaf pairs: LFP) increased canopy width, total leaf area, compactness index, number of branching and leaf and stem dry weight, but reduced plant height more than 40% when compared with non-pinching treatment. Leaving 2 or 3 LFP instead of 4 LFP after pinching only increased compactness index with marketable characters. None of the pinching times (10, 20 and 30 days after tuber planting: DAP) affected total leaf area, compactness index, number of branching and total leaf area. Pinching at 30 DAP gave the lowest leaf and root dry weight (DW). No interaction between pinching position and time in all growth parameters was seen, except in plant stem DW by leaving 2 or 3 LFP at 20 DAP after pinching. Experiment 2 showed that pinching seedlings with 2 LFP had low new tuber DW through all growth stages, however the underground part produced higher DW when reaching the harvesting stage. Higher reducing sugar accumulation in new tubers was found in normal plants (non-pinched) from flowering stage to senescence stage, thereafter its content declined compared to pinching plant at harvesting time. This result suggests that pinching technique might be partially a good horticultural practice to control JA height and canopy for the use as an ideal ornamental containerized plant.

Paclobutrazol (PBZ) is a plant growth retardant often used in potted ornamental plants to control their height and canopy for compactness. Helianthus tuberosus L., belonging to the Asteraceae family, has the potential to be developed as an edible ornamental potted plant. It has long lasting vivid yellow flowers and contains many nutritional tubers in the underground parts. However, an obstacle for commercialization is the control of the plant height. Therefore we evaluated different PBZ application methods (media drenching and tuber soaking) and concentrations (0, 50 and 100 ppm) on growth, flowering and inulin content of H. tuberosus The results show that PBZ concentration significantly reduced all growth parameters (plant height, canopy width and total leaf area), providing more compact plants of good commercial value, representing a reduction of compactness index (cm2 cm-1) and confirming its efficiency to reduce the vertical growth. None of the PBZ application methods affected plant height, canopy width, number of flowers, percentage of flowering and inulin content, while tuber-soaking treatment gave a reduction of total leaf area and compactness index. PBZ application at 50 ppm was sufficient to reduce plant height, total leaf area and compactness index compared with normal plants. Increasing the PBZ concentration seems to increase inulin content in tubers, although it seems to decrease the number of flowers.

Drought is a problem for peanut production as drought at any growth stage generally reduces pod yield and alters protein and amino acid compositions in kernels. The aim of work was to examine effects of terminal drought on arginine content in kernels of peanut genotypes with different levels of drought tolerance. Five peanut genotypes were planted under two water treatments, field capacity (FC) and 1/3 available water (1/3 AW). Arginine content, physiological traits and pod yield were recorded at harvest. The results showed that drought increased arginine content in sensitive and resistant genotypes, and the increase in arginine content was highest in sensitive genotype (Tainan 9). The variation in arginine content in peanut depended on peanut genotype rather than the level of drought resistance. No correlation between arginine content and drought-resistance physiological traits and pod yield were not found. These findings indicated that arginine content and resistance to terminal drought in a peanut may be improved simultaneously through selection in a breeding program.

In this work, the effects of co-inoculation between an arbuscular mycorrhizal fungus (AMF) and a phosphate solubilizing bacteria (PSB) to promote the growth and production of sunchoke under field condition were investigated during 2016 and 2017. Four treatments were set up as follows: plants without inoculation, with AMF inoculation, with PSB inoculation and with co-inoculation of PSB and AMF. The results showed the presence of PSB and AMF colonization at the harvest stage in both years. This suggested the survival of PSB and successful AMF colonization throughout the experiments. According to correlation analysis, PSB positively affected AMF spore density and colonization rate. Also, both AMF and PSB positively correlated with growth and production of sunchoke. Co-inoculation could enhance various plant parameters. However, better results in 2016 were found in co-inoculation treatment, while AMF inoculation performed the best in 2017. All of these results suggested that our AMF and PSB could effectively promote growth and production of sunchoke under field conditions. Such effects were varied due to different environmental conditions each year. Note that this is the first study showing successful co-inoculation of AMF and PSB for promoting growth and yield of sunchoke in the real cultivation fields.

Diurnal photosynthesis responses of cassava cultivar Rayong 9 ('RY9') three months after planting, grown in a field conditions under irrigated and rainfed conditions, were evaluated during the rainy, cool, and hot seasons. Under the mild conditions of the rainy and cool seasons, net photosynthetic rates (PN) increased in parallel with light intensity and attained the maximum at 13.00 or 11.00 h. In the hot season, PN attained the prominent peak at 9.00 h, after which stomatal conductance decreased rapidly coordinated with declining PN and nonphotochemical quenching was enhanced. Photosynthetically active radiation was the major factor influencing PN in the rainy and cool seasons, whereas vapor pressure deficit was the major factor in the hot season. 'RY9' adapted extremely well in this climate because the maximal quantum yield of PSII photochemistry recovered fully in the evening even under the rainfed conditions in the hot season.

Seasonal variations in photosynthesis of cassava cv. Rayong 9 (RY9) under irrigated and rain-fed conditions were evaluated at the age of three and six months after planting (MAP). Photosynthetic light-response (PN/I) curves revealed that cassava leaves attained the highest maximum net photosynthetic rates (PNmax) in the rainy season, followed by the hot one, while the lowest PNmax was found in the cool season. Photosynthetic potential of the 3-month-old plants was mostly higher than that of the 6-month-old plants, and the seasonal variation in photosynthetic capacity was also more apparent in the younger plants. PN/I curves were used to predict daily net photosynthetic rate (PN) for each season based on daily average solar radiation data. The predicted PN were considerably lower than the PNmax values. This indicated that solar radiation is a limiting factor for photosynthesis, particularly in the rainy season. The data provided basic information for breeding cassava genotypes with enhanced photosynthesis during the period of unfavorable environment. Furthermore, the data are potentially useful in modeling photosynthesis and crop growth as affected by environmental factors.

The chromatographic separation of Helianthus tuberosus L. (Jerusalem artichoke) flowers led to the isolation of twenty three compounds (1-23). They were characterized into four classes, terpenoids, flavonoids, coumarins and chromones, based primarily on the analysis of spectral data including IR, 1D and 2D NMR (1H, 13C, COSY, NOSEY, HMQC, and HMBC). The antiproliferative activity against colon cancer cell lines HT29 and HCT116, cytotoxicity against Vero cells and antimicrobial activity against E. Faecium ATCC 51559, P. aeruginosa PAO1, A. Baumannii ATCC 19606, K. Neumoniae ATCC 700603 and M. tuberculosis H37Ra (TB) were evaluated. Feradiol (9) exhibited a significant growth inhibitory effect against both cell lines (IC50 values of 3.93 ± 0.52 and 6.02 ± 0.33 μg/mL at 72 h respectively). The ent-kaur-16-en-19-oic acid (1) and β-sitostenone (14) exhibited weak antimicrobial activity against E. faecium with the same MIC values in the range of 6.25–12.50 μg/mL. In addition, 14 showed weak anti-TB with a MIC of 25.00 μg/mL. To the best of our knowledge, this is the first report on the chemical constituents and their biological activities from H. tuberosus L. flowers.

Plant physiological and photosynthetic responses to drought among Jerusalem artichoke genotypes possessing different levels of drought resistance are still lacking. We investigated the physiological and photosynthetic responses to drought of six Jerusalem artichoke genotypes differing in drought-resistance levels and evaluated the contribution of physiological and photosynthetic traits to tuber yield under drought condition. The split-plot in randomized complete block design with four replications was used. Six Jerusalem artichoke genotypes as sub-plots were nested in two water regimes (100% ET and 50% ET) as main plots. Relative water content (RWC) was recorded at 30, 60, and 90 days after transplanting (DAT), while SPAD chlorophyll meter reading (SCMR), net photosynthetic rate (Pn), stomatal conductance (gs), and leaf area (LA) were recorded at 30 and 90 DAT. Biomass and tuber yield were recorded at harvest stage. Water deficit restricted RWC by 20.45%, LA by 23.29%, Pn by 9.87, gs by 40.315, biomass by 42.62, and tuber yield by 46.13%, yet increased SCMR (6.74%) of six genotypes. The reductions observed on all traits of drought-resistant genotypes were smaller than that of susceptible genotypes. A drought-resistant genotype KT 50-4 showed a low tuber yield reduction (36.59%) and LA (16.34%) under water deficit condition, whereas KT 50-4, JA 60, and JA 125 had low reductions of Pn (7.06–9.75%) and gs (15.40–42.86%) under water deficit condition. While LA had a significant contribution to tuber yield under fully irrigated (80.11%) and drought (85.57%), Pn and SCMR had smaller contributions to tuber yield under drought condition (3.73% and 12.65%). Our results indicated that improvement of LA could contribute to high tuber yield under limited water conditions.

Endophytic fungi (EPF) and arbuscular mycorrhizal fungi (AMF) symbioses can promote the growth and productivity of several types of plants. This work aimed to investigate the effect of co-inoculation of an EPF Exserohilum rostratum NMS1.5 and an AMF Glomus etunicatum UDCN52867 g.5 on the growth and yields of sunchoke (Helianthus tuberosus L.) compared to the effects of full-dose and half-dose chemical fertilizer (15–15–15) under field conditions. Several plant growth parameters of the co-inoculated plants were significantly higher than the other treatments. Remarkably, such an effect was relatively equal to that of the full-dose chemical fertilizers. Moreover, the co-inoculation of EPF and AMF significantly improved the tuber yield production, even better than the use of a chemical fertilizer. This is the first report to show that plant growth promoting effects of the co-inoculation of EPF and AMF were exceptionally greater than those of the chemical fertilizer. Therefore, our EPF and AMF could potentially be used as a biofertilizer for promoting the growth and yield of sunchoke in the fields.

The endophytic bacteria isolated from the leaves, stems, tubers and roots of Helianthus tuberosus L. (Jerusalem artichoke) were studied and characterized. The isolated endophytes were clustered by amplified ribosomal DNA restriction analysis (ARDRA) technique and identified by 16 S rRNA sequencing to demonstrate bacteria diversity, mainly in Bacillus, Pseudomonas, Stenotrophomonas, Microbacterium, Curtobacterium. The proportions of endophytes exhibited colonization (from most to least) in stems, leaves, roots and tubers. The more isolates had ACC (1 aminocyclopropane-1-carboxylate) deaminase and nitrogen fixation, the less they showed phosphate and potassium solubilization. Antifungal activity was exhibited only in Bacillus, while many isolates had stress tolerance in polyethylene glycol. Six endophytic bacteria were recolonized into 2 varieties of Jerusalem artichoke (HEL65 and JA102xJA89) and showed increases in height, root and stem weight, and tuber number. The potential local endophyte, Pantoea ananatis 4.14 responded to the tuber by increasing inulin content, which is a valued product of Jerusalem artichoke.

Helianthus tuberosus L. (sunchoke or Jerusalem artichoke) has been widely applied in food and industrial products. Due to its economical benefits, sunchoke has been of great interest in many areas. Therefore, the aims of this study were to isolate fungal endophytes from sunchoke and screen for their ability to produce IAA, GA3 and other plant growth-promoting (PGP) agents. Among a total of 126 isolates, 4 most effective PGP strains were identified as C. gloeosporioides CPS3/5, G. cingulate NMS1.4, E. rostratum NMS1.5 and Xylariaceae sp. KKL3. In the pot experiments, several plant growth parameters such as plant height, diameter of stem, SPAD chlorophyll content, plant biomass, plant root growth, the number of tubers and tuber inulin content in sunchoke inoculated with these fungal endophytes were significantly higher than those of the uninoculated controls. Outstandingly, E. rostratum NMS1.5 exhibited the best performance on promoting growth and yield of sunchoke. Interestingly, strain NMS1.5 is the first member of E. rostratum that is beneficial to plant growth without causing any negative effects. This study suggested that our fungal endophytes can be effective plant growth promoters for use as biofertilizers for sunchoke production.

Winged beans (Psophocarpus tetragonolobus (L.) DC.) are grown as a vegetable legume crop in Thailand. All parts of the plant, including pods, seeds, leaves, flowers, and tubers are edible and are rich in protein and nutrients. Although the major consumption of winged bean is based on pod and tuber yields, only the people of Myanmar and Indonesia utilize winged bean tubers as food materials. The usefulness of the winged bean as an alternative crop for staple food and feed can shed some light on the impact of winged bean. Therefore, the evaluation of the dual purpose of the winged bean based on pod tuber yields is the objective of this study. In this study, ten-winged bean accessions—six accessions obtained from introduced sources and four accessions obtained from local Thai varieties—were laid out in randomized complete block design (RCBD) with three replications at the Agronomy Field Crop Station, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand from September 2019 to April 2020 and from October 2020 to April 2021. Data, including total pod weight, number of pods, pod length, 10-pod weight, and tuber weight were recorded, and the proximate nutrient and mineral contents in the tubers were also determined. The results revealed that the principal effects of year (Y) and genotype (G) were significant for total pod weight and the number of pods. Moreover, the Y × G interactions were principal effects upon the total pod weights and tuber weights. The results indicated that superior genotype and appropriate environmental conditions are key elements in successful winged bean production for both pod and tuber yields. The winged bean accessions W099 and W018 were consistent in both experimental years for pod and tuber yields at 23.6 and 18.36 T/ha and 15.20 and 15.5 T/ha, respectively. Each accession also proved high in tuber protein content at 20.92% and 21.04%, respectively, as well as significant in fiber, energy, and minerals. The results suggest that the winged bean accessions W099 and W018 can be used for dual-purpose winged bean production in Thailand.

Drought severely limits crop yield of peanut. Yet cultivars with enhanced root development enable the exploration of a greater volume of soil for water and nutrients, helping the plant survive. Root distribution patterns of three genotypes (ICGV 98305, ICGV 98324 and Tifton-8) were compared when grown in well-watered rhizoboxes and when grown in rhizoboxes where an early-season drought was imposed using rain-exclusion shelters. The treatments were arranged in a completely randomized design with three replications, and the experiment was conducted during two seasons at the Field Crop Research Station of Khon Kaen University, in Khon Kaen, Thailand. The root system of ICGV 98305, when grown under drought, had a significantly higher root length in the 30–110 cm deep soil layers and less roots in the 0–30 cm soil layers when under drought than when grown under well-watered conditions. Roots of Tifton-8 had the largest reductions in root length in upper soil layer and reduced in most soil layers. Tifton-8 grown under drought was smaller than under well-watered control for all root traits, showing negative response to drought. The peanut genotypes with high root traits in deeper soil layer under early-season drought might contribute to drought avoidance mechanism.

The impact of water stress on plant growth, tuber yield and inulin content has been widely studied but there is limited information on the effect of drought on photosynthetic characteristics. Therefore, this study was to investigate the effect of water stress on photosynthetic characteristics in Jerusalem artichoke genotypes with different levels of drought tolerance. Two experiments were conducted in rhizobox under greenhouse conditions during August to October in 2015 and 2016. A factorial experiment in randomized complete block design with three replications was used. Factor A were two water regimes (irrigated = field capacity; (FC) and water stress) and factor B were three Jerusalem artichoke genotypes. Data were recorded for relative water content, SPAD chlorophyll meter reading (SCMR), photosynthetic characteristics and water use efficiency (WUE) at 7 and 30 days after imposing drought. Leaf area and dry matter was recorded at 30 days after imposing drought. Our results revealed that drought caused a greater reduction in stomatal conductance ( g s ), net photosynthetic rate (P n ), leaf area and biomass production than in other traits measured. In contrast, WUE and SCMR were increased under drought conditions. However, g s and P n decreases were less in resistant Jerusalem artichoke genotypes than in susceptible genotypes. Also, resistant genotypes had higher WUE increases than susceptible genotypes. Improved P n combined with high WUE could contribute to higher biomass production. Interestingly, SCMR was associated with P n and this trait could be used as surrogate trait for improved P n under drought conditions.

Influences of harvest time and storage conditions on activities of fructan:fructan1-fructosyltransferase (1-FFT) and inulin hydrolase (InH) in relation to inulin and soluble sugars of Jerusalem artichoke (Helianthus tuberosus L.) tubers were investigated. Maturity affected 1-FFT-activity, inulin contents, and inulin profiles of the tubers harvested between 30 and 70 days after flowering (DAF). Decreases in 1-FFT activity, high molecular weight inulin, and inulin content were observed in late-harvested tubers. The tubers harvested at 50 DAF had the highest inulin content (734.9 ± 20.5 g kg−1 DW) with a high degree of polymerization (28% of DP >30). During storage of the tubers, increases in InH activity (reached its peak at 15 days of storage) and gradual decreases in 1-FFT activity took placed. These changes were associated with inulin depolymerization, causing decreases in inulin content and increases in soluble sugars. As well, decreasing storage temperatures would retain high inulin content and keep low soluble sugars; and freezing at −18 °C would best retard 1-FFT, InH, and inulin changes.

Information on macronutrient uptake and nutrient use efficiency (NUE) of cassava genotypes under different planting dates is limited. The aims of this study were 1) to investigate the responses of cassava genotypes to planting dates for nutrient uptake and NUE and 2) to identify the superior genotypes based on these traits. Three cassava genotypes (Kasetsart 50 (KU50), Rayong 11 (RY11) and CMR38-125-77) were planted in a randomized complete block design with four replications at four planting dates (20-Apr, 30-Jun, 5-Oct and 15-Dec 2016) and harvested at 12 months after planting (MAP). Planting cassava on 20-Apr and 15-Dec produced the highest total crop nutrient uptake and nutrient uptake for storage roots. Whereas planting cassava on 5-Oct and 15-Dec with higher solar radiation, temperature, relative humidity and longer photoperiod during canopy establishment until high carbohydrates translocation and with lower temperature and shorter photoperiod during a dormancy period resulted in greater NUE for biomass and storage roots and nutrient harvest index for all genotypes and most elements. CMR38-125-77 and KU50 showed good performance in terms of total nutrient uptake across planting dates (1.45–38.31 g plant−1) for most elements. CMR38-125-77 seems to be the best genotype on the basis of high storage root dry weight, high NUE for both biomass (90.1–1,594.6) and storage roots (39.9–927.1) and nutrient harvest index (0.14–0.58) for almost all planting dates, except in planting date 20-Apr in which RY11 was the highest for these traits. The genotype identified is useful as parental source for further breeding programs to improve genotypes with high NUE and high storage root yield.

Arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) could interact synergistically because PSB solubilize sparingly available phosphorous compounds into orthophosphate that AMF can absorb and transport to the host plant. Little is known about the interactions between these two groups in terms of promoting Jerusalem artichoke, Helianthus tuberosus L., which is widely planted by farmers because of its high inulin content. Production depends mainly on synthetic fertilizers as source of plant nutrients. This study aimed to isolate and characterize PSB and investigate the effects of co-inoculation of AMF and PSB on plant performance and inulin accumulation. Isolate UDJA102x89-9, identified as Klebsiella variicola (KV), showed phosphate-solubilizing ability and produced high amounts of several organic acids in vitro and of indole-3-acetic acid (IAA). The experiment combined KV and two AMF species (Glomus multisubtensum (GM) and Rhizophagus intraradices (RI)). Co-inoculation of KV with RI, in combination with rock phosphate, showed the largest increases in plant growth and tuber inulin content, compared both to an unfertilized and fertilized control. This result would reveal whether the phosphate solubilization and IAA property of the PSB in vitro played a significant role in changing plant growth and production, and the available P was subsequently taken up and transported to plant roots by AMF. The high combined effect may have the potential for use by farmers in the future as a biofertilizer for inulin production by Helianthus tuberosus L.

The objectives of this study were to evaluate the efficacy of integrating resistant genotypes of Jerusalem artichoke with Trichoderma harzianum isolate T9 to control Alternaria leaf spot caused by Alternaria spp. under two fertilization regimes and to determine whether T9 application induced chitinase and β-1,3-glucanase activity in Jerusalem artichoke leaves. Six Jerusalem artichoke varieties (resistant varieties JA15, JA86, and JA116 and susceptible varieties HEL246, HEL293, and JA109) and three disease control methods (a non-inoculated control, application of T. harzianum T9, and fungicide sprays (propiconazole at a rate of 30 mL/20 L of water, 375 ppm)) was conducted in two separate trials (different fertilization regimes) at the experimental farm of the Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand. Resistant genotypes controlled Alternaria leaf spot effectively. Application of Trichoderma showed low efficacy to control Alternaria leaf spot, but in specific susceptible genotypes—HEL246 and HEL293—the application of Trichoderma could reduce disease severity up to 10%. The application of Trichoderma was associated with a rise in production of chitinase and β-1,3-glucanase in HEL246 seedlings. The number of Trichoderma propagules in soil, as well as the extent of colonization of roots and leaves, were monitored. The results indicated that application of Trichoderma had higher propagules than non-inoculated control. Neither varietal resistance nor the disease control methods used in this study impacted the yield or yield components of Jerusalem artichoke.

Drought is more concerned to be a huge problem for agriculture as it affects plant growth and yield. Endophytic bacteria act as plant growth promoting bacteria that have roles for improving plant growth under stress conditions. The properties of four strains of endophytic bacteria were determined under water deficit medium with 20% polyethylene glycol.

Selecting the appropriate genotypes for particular planting dates may help increase cassava productivity. The CSM–MANIHOT–Cassava model is a new tool to support decision making for crop management. However, it is important to explore the potential of a model prior to any application. The objective of this study was to evaluate the CSM–MANIHOT–Cassava model in simulating the performance of cassava genotypes for different planting dates. An experiment with four cassava genotypes and eight planting dates was conducted on the experimental farm of the Faculty of Agriculture at Khon Kaen University, Thailand, under optimum conditions. The data for soil and weather conditions, crop management, and crop traits were recorded. The cultivar parameters were determined using experimental data for three planting dates, while the remaining five planting dates were used for model evaluation. A scenario analysis for different planting dates using historical weather data from 2003 to 2018 was also conducted. The calibration results showed a good agreement between simulated and observed phenology and crop traits. Model evaluation based on the d-index showed a good agreement between simulated and observed total crop, stem, and storage root dry weights with values above 0.8 for almost all four genotypes and five planting dates. The model provided acceptable outputs for final total crop dry matter and storage root yield. The results from both the scenario analysis with the CSM–MANIHOT–Cassava model and the actual experiment classified Kasetsart 50 and CMR38–125–77 as one out of the top two genotypes based on final total crop biomass, demonstrating the potential of the model to help identify promising cassava genotypes.

The impacts of light sources on development, morphological characteristics, and chlorophyll fluorescence of Jerusalem artichoke (Helianthus tuberosus L; JA) seedlings were investigated under natural light (NL), fluorescence light (FL), red light LEDs (R), blue light LEDs (B) and red + blue light LEDs (R + B) (photosynthetic photon flux density 326.74, 30.61, 159.23, 445.38 and 332.56 μmol m−2·s-1, respectively). Morphological appearances of seedlings were significantly different, The R and R + B lighting significantly reduced seedling height and internode length when compare with NL. In contrast, B light could enhance JA seedling growth by increase stem dry weight and net assimilation rate (NAR). Photosynthetic efficiency in terms of photochemical quenching (qP) of seedling were higher under B light than FL light. JA response of seedlings under B light condition was much overall better yield compare to another light source condition. Taken together, R and R + B lighting facilitated plant shortening and more compact canopy, emphasizing the importance of R light spectral quality to manipulate plant growth. It therefore represents modify alternative method to obtain edible potted JA plants under control lighting.

Due to its increasing economical values, sunchoke is widely planted including in Northeast Thailand where insufficient water supply recurs. This work then aimed to investigate the efficiency of 5 different AMF species to enhance growth of sunchoke under drought stress conditions. Factorial experiments in a randomized complete block design (RCBD) were conducted with four replications under two conditions, a well-watered (WW) and a drought stress (DS). This result showed that Rhizophagus irregularis BM-2 g1, Glomus hoi KKU g3 and Rhizophagus aggregatus BM-3 g3, were the best AMF to enhance the growth and yield of sunchoke. We found that Glomus etunicatum UDCN52867 g5 less affected the growth of sunchoke when compared to the other Glomus spp. in this work. Different AMF species belonging to Glomales affected different plant growth parameters at different levels. This suggested a variety of plant growth promoting functions of Glomus spp. Moreover, Acaulospora mallea KKU-NBP-SB-2, isolated from Eucalyptus plants, did not significantly enhance the growth and yield of sunchoke under both WW and DS conditions. This suggested that plant-AMF symbiosis is a species-specific interaction. Detailed mechanisms of AMF and an application of a combination of AMF species with different functions to enhance sunchoke growth are worth investigating.

The distribution patterns of peanut roots in response to different durations of drought events might affect water acquiring capacity of peanut and this information has not been clearly investigated. In this study, the response to different durations of drought in root distribution was evaluated in peanut genotype ICGV 98305 for three seasons in rhizoboxes in a rainout shelter at Khon Kaen University. Two seasons of this study were in 2013 and one in 2014. The first and the second trials were conducted in the rainy season and the third trial was carried out in the dry season. A completely randomized design with three replications was used. Drought treatments were imposed at 14 days after emergence. The durations of drought imposition were 7, 14 and 21 days after the irrigation withholding. Root samples were divided into 11 soil layers at 10 cm intervals from the top to the bottom of the rhizobox. Drought imposed to peanut at early growth stages could change root distribution patterns of peanut, and the change in root distribution patterns was more pronounced with long duration of drought. In this study, imposing of drought for 21 days caused a clear difference of root distribution patterns between peanut grown under well-watered (WW) and under drought stress (DS) treatments. The peanut adaptation to severe drought appears to be through enhanced root length and the root system growing deeper. The knowledge obtained is useful to decide the duration of drought that causes discernible modification in root system and can help identification of genetic variation for such adaptation. As water stress can mean excess water stress too, generally the expression drought stress is adopted.

The objectives of this study were to determine the effects of drought on tuber yield, total biomass, harvest index, water use efficiency of tuber yield (WUEt) and water use efficiency of biomass (WUEb), and to evaluate the differential responses of Jerusalem artichoke (JA) varieties under drought stress. The 3 × 5 factorial combinations of three water regimes (Field capacity (FC), 50% available soil water (50%AW) and 25%AW), and five JA varieties (JA 60, JA 125, JA 5, JA 89 and HEL 65) were arranged in a pot experiment in a randomized complete block design with four replications for two years. Data were recorded for tuber dry weight, total biomass, harvest index, WUEt and WUEb at harvest. Drought reduced tuber dry weight, total biomass, harvest index, WUEt and WUEb, and reductions were more severe under the severe drought stress of 25%AW. Varieties were significantly different for all traits under drought and well-watered conditions. The JA varieties were classified into three groups. The first category was comprised of the JA 5 variety with high tuber yield potential and low drought tolerance, the second category consisted of JA 60 and JA 125 varieties with low tuber yield potential and high drought tolerance, and the third group included JA 89 and HEL 65 varieties with low tuber yield potential and low drought tolerance. The multiple regression analysis showed that tuber yield, total biomass and harvest index at 50%AW and 25%AW depended largely on the reductions of tuber yield, total biomass and harvest index under drought. Therefore, the results of this study recommend that the selection of JA genotypes with low reduction in yield under drought stress could be a criterion in drought resistance breeding programs for development of JA varieties with high tuber yield under drought stress. JA with drought tolerance in this study means high tuber yield under drought conditions. JA 5 had high yield and WUEt across water regimes and could be used as parental source for drought tolerance breeding programs in further research.

Stem rot caused by Sclerotium rolfsii is an important problem of Jerusalem artichoke, and breeding of Jerusalem artichoke for resistance to stem rot requires effective screening methods. The objective of this study was to compare methods for inoculating Jerusalem artichoke with S. rolfsii under field conditions. A 4 × 2 × 3 factorial in a randomized complete block with four replications was used in two environments characterized by different rates of fertilizer application (recommended rate and low rate) in the rainy season. The factors included four Jerusalem artichoke varieties (HEL280, HEL278, HEL256 and JA49), two levels of wounding (wounded and not wounded) and three methods of inoculation. The inoculation methods consisted of: 1) non-inoculated natural infection; 2) attaching one colonized sorghum seed at the crown of plants (single sorghum seed method); and 3) spreading 30 g m−2 of colonized sorghum seeds (broadcast inoculation method). Jerusalem artichoke varieties and inoculation methods were significantly different for disease incidence, whereas the difference between wounded and non wounded treatments was not significant. Significant interactions were found between the variety and wounding method, the variety and inoculation method, wounding method and inoculation method, and inoculation method and environments. Natural infection resulted in the lowest disease incidence (32.2 %), whereas the single sorghum seed and the broadcast inoculation methods had a high disease incidence (79.0 % and 77.3 % respectively) and were not signnificantly different from each other. Broadcast inoculation did not allow differentiation of Jerusalem artichoke varieties for disease incidence, whereas single seed inoculation could better identify the differences among Jerusalem artichoke varieties.

Drought is a major constraint in peanut production. Drought not only reduces pod yield but also may affect phenolic compounds in peanut. This experiment was conducted for two years under field conditions. Soil moisture levels (field capacity and mid season drought stress) were assigned as main plots, and five peanut genotypes were assigned as sub plots. Peanut seeds were analyzed for phenolic compounds at harvest. Leaves and stems were also analyzed at 30 and 60 days after planting (DAP), and at harvest. Water regimes did not result in significant differences for phenolic compounds in seeds, whereas peanut genotypes were significantly different for this trait. Drought increased phenolic contents in leaves at 60 DAP and phenolic contents were reduced during the recovery period. The production of leaf phenolic compounds differed among genotypes. Mid season drought increased phenolic compounds in stems during the drought period and levels of phenolic production were different depending on peanut genotype. Breeding for high phenolic content and drought tolerance in peanut should be possible because mid season drought did not affect phenolic content in seeds.

This study is aimed to investigate the antifungal activity of endophytic fungi isolated from Jerusalem artichoke (Helianthus tuberosus) and Ginger (Zingiber officinale) and Stemona root (Stemona tuberosa) against causative agent of southern stem rot Sclerotium rolfsii. The dual assay results showed that out of 110 fungal endophytes, Diaporthe phaseolorum BUP3/1 and Macrophomina phaseolina BUP2/3, isolated from Jerusalem artichoke and Daldinia eschscholtzii 2NTYL11 and Trichoderma erinaceum ST-KKU2, isolated from Stemona root and ginger could effectively inhibited the mycelial growth of S. rolfsii at 76.00, 41.20, 66.67 and 63.63%, respectively. The β-1,3 glucanase and chitinase activities of all endophytic fungi was determined which reached the maximum after 2 and 7 days of incubation, respectively. In addition, Scanning Electron Microscope (SEM) observation showed that T. erinaceum ST-KKU2 has predatory mechanism aginst S. rolfsii via coiling and invasion. Interestingly, our endophytic fungi T. erinaceum ST-KKU2 and D. eschscholtzii 2NTYL11 were the first species in their genera to produce polyketides group as 6-n-pentyl-2H-pyran-2-one (6PAP) and 2,3-dihydro-5-hydroxy-2-methyl-4H-1-benzopyran-4-one (DHMB), respectively, to control S. rolfsii. Moreover, the antagonistic mechanisms of all endophytes were determined in vivo under greenhouse condition. The endophytic fungi, T. erinaceum ST-KKU2 and D. eschscholtzii 2NTYL11 also showed high level of reduction of southern stem rot disease by 58.14% under pot experiment. Such effects were also higher than the effects of other endophytic fungi isolated from Jerusalem artichoke when tested under greenhouse condition. Our experiments showed the fungal endophytes isolated have potential for further development as a biocontrol agent in the future.

Endophytic fungi were able to protect their host plants against pathogens and promote plant growth. No previous studies have been conducted on the growth promotion of sunchoke by endophytic fungi. This research was the first to characterize plant growth promoting properties of endophytic fungi including, Macrophomina phaseolina BUP2/3 and Diaporthe phaseolorum BUP3/1 isolated from sunchoke and Daldinia eschscholtzii 2NTYL11, Trichoderma koningii ST-KKU1, Trichoderma erinaceum ST-KKU2, Macrophomina phaseolina SS1L10 and Macrophomina phaseolina SS1R10 from medicinal plants. Also, their plant growth promoting efficiency in artichoke plants under greenhouse condition was evaluated. The highest phosphate solubility and production of extracellular enzymes including amylase, protease, cellulase and xylanase were found after 5 and 21 days of incubation, respectively. Moreover, Indole-3-Acetic Acid (IAA) in the crude extracts of fungi isolated from Jerusalem artichoke was higher than that from medicinal plants (p ≤ 0.05). HPLC analysis suggested the putative IAA biosynthesis pathways in our fungi were via Indole-3-lactic acid (ILA) and Indole-3-acetamide (IAM). In the pot experiment, the values of height, diameter, chlorophyll content and leaf dry weight in sunchoke plants inoculated with fungal endophytes were significantly higher than those of un-inoculated plants. Therefore, this study suggested that fungal endophytes could be used as a biofertilizer for promoting growth of sunchoke.

As a secondary crop planting in the double-cropping system, terminal drought is the major constraint of Jerusalem artichoke production in the rainfed area. This study aims to estimate the effects of different durations of terminal drought on total biomass, tuber yields, harvest index, yield components, and to identify high yield potential and low yield reduction genotypes for the varietal improvement program. A split-plot design with four replications was conducted under field experiment for two years. Three drought durations including non-drought stress (SD0), drought from 60 and 45 days after transplanting until harvest (SD1 and SD2, respectively), were assigned in main plots and six genotypes were arranged in subplots. Crop parameters were greater decreased under a long-drought duration than under short-drought duration. The genotypes were identified, HEL256, JA37 and JA125 had high yield potential under SD0 conditions, whereas there was high yield reduction under drought conditions. In contrast, JA60 and HEL253 were identified as low yield potential and low yield reduction genotypes. This information suggested that high yield potential genotypes and low yield reduction genotypes should be selected and generated progeny population for improvement of new varieties with high yield potential and low yield reduction for growing in terminal drought-prone environments.

Additional information on the physiological performances for different cassava genotypes would support better decision-making about desirable genetic resources for water-limited conditions. The objective of this study was to evaluate the physiological expression and yield of eight different cassava genotypes grown under a dry environment during high storage root accumulation. The eight cassava genotypes, i.e., Kasetsart 50, Huay Bong 80, Rayong 5, Rayong 7, Rayong 9, Rayong 11, Rayong 90, and CMR38-125-77 were evaluated under rain-fed upland conditions at Khon Kaen University, Thailand, during 2018 to 2020. A randomized complete block design (RCBD) with three replications was used. Soil moisture contents, chlorophyll fluorescence (Fv/Fm and Fv&prime, /Fm&prime, ), net photosynthesis (Pn), stomatal conductance, water use efficiency (WUE), relative water content (RWC) for leaf, leaf area index (LAI), specific leaf area (SLA), starch content, crop dry weight, and starch yield were observed at 180, 270, and 360 days after planting (DAP), and weather data during the experimental period were also recorded. The results from both 2018/2019 and 2019/2020 indicated that Pn was positively and significantly correlated with stomatal conductance and Fv/Fm during the high storage root accumulation stage (270 and 360 DAP) with soil moisture content lower than field capacity. CMR38-125-77 had satisfactory performances in Pn, RWC, Fv/Fm, Fv&prime, stomatal conductance, LAI, SLA, WUE, biomass, starch content, and starch yield at a last growth stage with soil moisture content lower than permanent wilting point. Significant association between crop dry weight and WUE at 360 DAP was recorded, and CMR38-125-77 and Kasetsart 50 were classified as favorable genotypes with high WUE and biomass.

Although cassava can be planted throughout the year, its starch qualities may vary based on the date of planting. Seasonal variation on starch content, starch yield, starch granule size and amylose content of cassava cv. Rayong 9 grown under irrigated and rainfed conditions were studied for four planting dates in Thailand. A randomized complete block design with four replications was used in each planting. Planting dates consisted of hot-dry (20-Apr), early-rainy (30-Jun), late-rainy (5-Oct) and cool seasons (15-Dec). At final harvest, planting date accounted for the largest variations for starch yield (60.8%), starch granule size (38.2%), amylose content (50.5%) and ratio of amylose to amylopectin (53.7%), whereas starch content was affected more by water regime (52.1%). Supplemental irrigation did not significantly increase starch yield and other parameters for most planting dates, except for starch yield of the crop planted in the hot-dry season. This indicated that irrigation at the late-growth stages (during Sep to Mar) for the crop planted in the hot-dry season helped to increase starch yield, however, irrigation was unnecessary for other planting dates once cassava was established. The crops planted in the late-rainy and cool seasons had a greater starch content and starch yield than other planting dates for both irrigated and rainfed crops, whereas the crop planted in the hot-dry season had high starch yield for the irrigated crops only. In this study, the crops planted in the early-rainy season showed the worst performances for starch content and starch yield for both irrigated and rainfed crops. The data provided information on the responses of starch yield and its characteristics under irrigated and rainfed conditions at different planting dates, which can be useful for designing cultural practices with respect to water management and planting period in order to obtain optimum starch yield and qualities.

Phenolic compounds present in our diet play an important role in colon cancer chemoprevention. Previous results demonstrated that peanut testa extract inhibited both histone deacetylase (HDAC) activity and the growth of colon cancer cells. In this study, four identified phenolic compounds in peanut testae (resveratrol, p-coumaric acid, ferulic acid, and sinapinic acid) were investigated for their HDAC inhibitory and anticancer activities against colon cancer cell lines. In vitro study revealed that resveratrol exhibited the greatest HDAC inhibitory activity. Molecular docking studies demonstrated that all four compounds could bind both HDAC1 and HDAC2. Resveratrol exhibited the most effective antiproliferative activity against both human colon adenocarcinoma (HT29) and human colorectal carcinoma (HCT116) cells. Apoptosis induction by ferulic acid and resveratrol appeared to be associated with p53 activation in HCT116 cells. However, resveratrol, p-coumaric acid, ferulic acid, and sinapinic acid induced apoptosis of HT29 cells in a p53-independent manner. Low-concentration treatments of p-coumaric and ferulic acids resulted in cell cycle arrest of HCT116 cells. In contrast, high-concentration treatments of p-coumaric and ferulic acids showed cell death activation as evidenced by increased sub-G1 fractions. The induction of p21 by p-coumaric acid and resveratrol correlated well with the decreased CDK4 levels and cell cycle arrest. Resveratrol, p-coumaric acid, ferulic acid, and sinapinic acid caused activation of pERK1/2 in HCT116 cells, whereas ferulic and sinapinic acids caused downregulation of pERK1/2 in HT29 cells. These results suggest that these peanut phenolics may be potential antineoplastic agents for colon cancer chemoprevention/chemotherapy.

Seasonal variations affect growth and yield of a crop, primarily by changing its phenological developmental processes. The objective of the present study was to evaluate seasonal variation effects on growth and development of Jerusalem artichoke. The experiment was conducted during the early-rainy seasons in June–September 2011 and the post-rainy seasons in September–December in 2011, and two seasons were repeated in 2012 at the Field Crop Research Station of Khon Kaen University. A randomize complete block design (RCBD) with 5 replications was used. Four Jerusalem genotypes including JA 89, HEL 65, CN 52867 and KT 50-4 were used. Results indicated similar phenological development between the early and post rainy-seasons. However, high temperature combined with long photoperiod during the early-rainy seasons delayed tuber initiation and extended maturity. Low temperature and short photoperiod was a favorable condition for tuber development but reduced vegetative and reproductive development. On average, tuber dry weights and tuber growth rate were higher in the post-rainy season compared to the early-rainy season. On the other hand, biomass and crop growth rates were higher in the early-rainy seasons compared to the post-rainy seasons. The knowledge obtained in this study is important for Jerusalem artichoke production and selection of Jerusalem artichoke genotypes in the tropical climate.

The objective of this study was to determine effects of drought on selected root growth parameters and develop relationships between root parameters and tuber yield for selected Jerusalem artichoke (JA) genotypes. Three water regimes (Field capacity, 50% available soil water (AW) and 25% AW) and five JA varieties (JA 60, JA 125, JA 5, JA 89 and HEL 65) were planted with factorial treatments in a randomized complete block design with four replications. Data on root dry weight (RDW) and root: shoot ratios (RSR) were measured manually. Root diameter (RD), root length (RL), root surface area (RSA) and root volume (RV) were collected at harvest. Drought tolerance indices (DTI) were calculated for all root parameters. Drought reduced all root parameters and DTI but increased RSR in JA 60, JA 125, JA 5, and HEL 65. JA 125 had high values for all root traits and DTI of these traits under drought stress. JA 60 had high DTI of RDW, RD and RSR under mild and severe water stress. JA 5 had high DTI of RDW, RD, RL, RSR and RV under drought conditions. JA 89 and HEL 65 performed well for RDW, RD, RL and low DTI of all root characteristics. DTI for root parameters were positively correlated with tuber dry weight under mild and severe water stress. The JA 5, JA 60 and JA 125 varieties showed high DTI for some root traits, indicating that better root parameters contributed to higher tuber yield under drought stress.

Inhibition of histone deacetylase (HDAC) is a promising strategy for cancer treatment. In this study, HDAC inhibitory activity of 15 Valencia-type peanut testa extracts was assessed in mammalian cell model. Nine of 15 testa extracts exhibited HDAC inhibitory activity. Two peanut testa extracts (genotypes ICG15042 and KK4) possessing the greatest HDAC inhibitory activity could inhibit the growth of all five human cancer cell lines tested. At 72-h treatment, both ICG15042 and KK4 testa extracts showed the most effective growth inhibition on Jurkat T-leukemia cells with IC50 values of 28.81 and 30.00 μg/mL, respectively. Both extracts were more toxic against the cancerous cell lines, but safer toward a noncancer cell line. Growth inhibitory effects of both extracts appeared to be mediated by induction of apoptosis in a dose-dependent manner. Moreover, some phenolic acids including protocatechuic, syringic, p-coumaric, ferulic and sinapinic acids, which may underpin their anticancer activity, were also identified and analyzed quantitatively. Practical Applications HDAC inhibitory potentials of phenolic-rich testa extracts of 15 Valencia-type peanut genotypes in mammalian cell model were evaluated. The results suggest that peanut skins (testae) of nine peanut genotypes possessed HDAC inhibitory activity and two of them (ICG15042 and KK4), with the highest HDAC inhibitory activity, could inhibit cancer cell growth via apoptosis induction. Accordingly, peanut skins could be useful for application in areas such as alternative medicine for cancer treatment and functional food for dietary prevention of cancer.

Stem rot caused by Sclerotium rolfsii is an important problem for Jerusalem artichoke production. Host plant resistance is the most promising method to control disease. If resistant genotypes can be identified in seedlings and this resistance is closely related to resistance at maturity, the evaluation of disease resistance in adult plants could be curtailed or omitted, increasing the speed and efficiency of screening. The objective of this study was to determine the relationship between resistance to S. rolfsii in Jerusalem artichoke in seedling and in adult stages under field conditions. Field experiments were set up in different soil fertility environments in the rainy season during July to October 2014. In each environment, 10 varieties of Jerusalem artichoke with differences in resistance to S. rolfsii were planted and inoculated either 15 or 45 days after transplanting. Higher disease incidence was observed on adult plant stage, but disease severity was similar for both plant stages. The correlations between seedling and adult responses were positive and significant for disease incidence, area under disease progress curve and severity index. Screening for resistance to S. rolfsii in Jerusalem artichoke can be carried out on seedlings, thus improving the efficiency of selection.

Previous studies demonstrated that peanut testa extracts (KK4 and ICG15042) containing natural histone deacetylase (HDAC) inhibitors inhibited the growth of several human cancer cell lines via apoptosis induction. The aims of this study were to investigate the anti-proliferative effects and the mechanism(s) responsible for apoptosis induction mediated by these peanut testa extracts in human cholangiocarcinoma cell lines (KKU-M214 and KKU-100). The anti-proliferative effects were assessed by MTT assay. Apoptotic cell death and cell cycle arrest were analyzed by flow cytometry. The caspase activities were studied using colorimetric caspase activity assay and western blot analysis. Our results revealed that KK4 and ICG15042 extracts inhibited cell proliferation of both KKU-M214 and KKU-100 cells in a dose- and time-dependent manner, with IC50 values of 38.28 ± 0.29 (KK4), 43.91 ± 1.94 (ICG15042) μg/mL for KKU-M214 and 78.40 ± 1.74 (KK4), 82.77 ± 0.94 (ICG15042) μg/mL for KKU-100 at 72 h. Apoptosis induction by these peanut testa extracts were observed in both KKU-M214 and KKU-100 cells in a concentration-dependent manner. Moreover, the percentage of cells in the sub-G1 phase was significantly increased in both KKU-M214 and KKU-100 cells. Cell cycle arrest was not observed in other cell cycle phases. Activation of caspases 8 and 3 were apparent integral parts of apoptosis induction in both cells. Both peanut testa extracts also caused down-regulation of p53, p21, Bcl-2 and pERK1/2 protein expression in these cells. These results suggest that peanut testa extracts may be potential anti-cancer agents for cholangiocarcinoma chemoprevention or chemotherapy.