Kamphaeng Saen Research Articles

QTLs CONTROLLING SEED WEIGHT AND DAYS TO FLOWERING IN MUNGBEAN [Vigna radiata (L.) Wilczek], THEIR CONSERVATION IN AZUKI BEAN [V. angularis (Ohwi) Ohwi & Ohashi] AND RICE BEAN [V. umbellata (Thunb.) Ohwi & Ohashi

Mungbean ( Vigna radiata (L.) Wilczek) is a socio-economically important legume crop of Asia. Varieties with large seed size and early maturity are preferred in commercial production. In this study, we identified quantitative trait loci (QTL) controlling seed weight and days to flowering in mungbean. The mapping population comprises 155 F 2 -derived lines from a cross between Kamphaeng Saen 1 (large-seeded and early flowering) and V4718 (small-seeded and late flowering). The F 2 population was analyzed with 67 simple sequence repeat markers. The F2:3 families were evaluated for 100-seed weigh and days to flowering in two years, 2008 (one season) and 2011 (two seasons). Composite interval mapping identified six QTLs for 100-seed weight and 5 QTLs for days to flowering. Three genomic regions harbored QTLs for both seed weight and days to flowering, revealing association between the two traits. Comparison of QTLs for both traits found in this study with those reported in azuki bean ( Vigna angularis (Willd.) Ohwi & Ohashi) and rice bean ( Vigna umbellata (Thunb.) Ohwi & Ohashi) revealed that several QTLs are conserved among the three Vigna species.

BREEDING FIELD CROPS FOR ORNAMENTAL PURPOSE: A CASE IN Jatropha spp.

Populations of F 1 , F 2 and BC 1 F 1 were formed from an interspecific cross between green-flowered Jatropha curcas and red-flowered J. integerrima (dwarf type) to observe for segregation in flower colors and to select for ornamental segregants. The crossing to produce F 1 and BC 1 F 1 was successful only when J. curcas was used as the female parent. The suitable time for crossing was between 08:00 – 13:00 o’clock with fruit setting rate of 65-78%. The F 1 segregated into white- and pink-flowered plants. While flowers of the F 2 population segregated into nine different colors, viz. light green, green, white, very light pink, light pink, pink, deep pink, very deep pink, and red. When J. curcas was backcrossed by a pink-flowered F 1 , its BC 1 F 1 progenies segregated into green, light green, white, very light pink and light pink flowers. While another set of BC 1 F 1 progenies obtained from a white-flowered F 1 parent segregated into green, light green, and white. The segregating progenies in both sets showed smaller plants than jatropha and bore colorful flowers suitable for ornamental purpose. Six plants were chosen and registered at Kasetsart University and the Thai Department of Agriculture as commercial cultivars, ‘Kamphaeng Saen 1’ to ‘Kamphaeng Saen 6’. Keywords: ornamental jatropha, interspecific cross, flower color, crossing durations

Mutualistic relationships between the shield ant, Meranoplus bicolor (Guérin–Méneville) (Hymenoptera: Formicidae) and honeydew–producing hemipterans in guava plantation

ABSTRACT – Mutualistic relationship between the shield ant, Meranoplus bicolor (Guerin–Meneville), and two species of hemipteran, Aphis gossypii Glover and Ferrisia virgata (Cockerell), was investigated in an unsprayed guava plot at Kamphaeng Saen, Nakhon Pathom, Thailand. The reciprocal benefits were observed in both field and laboratory studies. M. bicolor activity coincided with peak seasonal activity of both hemipterans during June–August. We indicate two sets of support evidence in M. bicolor honeydew preference: (i) statistically higher value of adjusted honeydew weight collected by ant worker from A. gossypii compared with that from F. virgata ( p –value = .005), and (ii) the higher value of the strength of effect (h 2 = .62) in the total variance of multi-species association. We used two–group, ant–tended and ant–excluded, between–subject multivariate analysis of variance (MANOVA) in order to show hemipteran benefits. Both hemipteran populations increased in the ant–tended treatment, together with lesser amounts of two species of coccinellids, Menochilus sexmaculatus (Fabricius) and Coccinella transversalis Fabricius, and one species of syrphid fly, Pseudodorus clavatus (Fabricius), compared with the ant exclusion treatment ( p –value <.0005). The facultative mutualistic relationships of M. bicolor and the two hemipteran species were evaluated.

‘Kamphaeng Saen 1’, ‘Kamphaeng Saen 2’, and ‘Kamphaeng Saen 3’: New Ornamental Jatropha Cultivars Derived through an Interspecific Cross

‘Kamphaeng Saen 1’, ‘Kamphaeng Saen 2’, and ‘Kamphaeng Saen 3’: New Ornamental Jatropha Cultivars Derived through an Interspecific Cross

Establishment of a core collection of chilli germplasm using microsatellite analysis

Chilli (Capsicum spp.) is an economically important vegetable and spice. The Tropical Vegetable Research and Development Center, Kasetsart University, Kamphaeng Saen Campus has collected more than 2500 chilli germplasm accessions since 1989. Investment to maintain and evaluate such a large germplasm collection is high. For efficient germplasm management and to reduce the cost of germplasm maintenance, a core collection needs to be established. Therefore, this study aimed to investigate the genetic diversity of chilli germplasm using microsatellites. A total of 230 chilli germplasm accessions were evaluated using ten anchored Capsicum microsatellite loci. These loci generated 42 alleles with a size ranging from 87 to 323 bp. The average polymorphic information content was 0.57, ranging from 0.414 to 0.681, and the probability of identity (PI) ranged from 0.17 to 0.49. The combined PI of the ten microsatellite loci was 2.30 × 10− 6. The similarity index ranged from 0.29 to 1.00. The 230 chilli accessions were divided into two major groups. Group I comprised mainly C. annuum, and group II comprised all four Capsicum species with the majority being C. frutescens, C. chinense and C. baccatum. The matrix comparison showed that a cophenetic correlation of 0.798 indicated the best fit of the obtained dendrogram. The PowerCore program selected 28 representative chilli accessions to form a core collection, which maintained a similar level of diversity to that of the overall 230 chilli accessions. The representative alleles in those 28 core accessions equalled all the alleles present in the entire collection.

Aquatic Insects Biodiversity and Water Quality Parameters of Receiving Water body

Biodiversity of aquatic insect and physicochemical water quality parameters in receiving water bodies in Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom Province, central Thailand were assessed during October 2010 to September 2011. Seven sampling stations, each 100 m long, were established. Three replicates of samplings by aquatic D-net were used at sampling sites. A total of 4,257 individual of aquatic insect were collected during one year. Six Orders and 12 families were recorded in this study. The family Hydropsychidae and Chironomidae were the most abundance of aquatic insects that found in receiving water bodies. The CCA revealed the family Mesoveliidae and Chironomidae were correlated with alkalinity in receiving water bodies, whereas dissolved oxygen was correlated with family Baetidae, Coenagrionidae, Hydrophilidae, and Helotrephidae. Signs of increasing water quality deterioration were evident in the result of the physicochemical analyses.

Combining bio-pesticides with chemical pesticides to manage legume pod borer (Maruca vitrata) on yard-long bean in Thailand

This study aims to confirm the potential of bio-pesticide application under field conditions in combination with chemical pesticides against the pest moth Maruca vitrata on yard-long bean. Four field trials were conducted at two locations (AVRDC East and Southeast Asia Regional Research and Training Station, and farmers’ fields in Kamphaeng Saen, Thailand) from March to May 2012 and May to August 2012. The yard-long bean pod damage by M. vitrata was significantly reduced by 23–85%, with substantial yield increases (22–190%) in Bacillus thuringiensis-based treatments in combination with cypermethrin, when compared with the untreated check. Although the combined effect of cypermethrin with Beauveria bassiana or neem-based treatments was better than the untreated check, the pod damage was still higher in these treatments, recording up to 26.87% compared with B. thuringiensis subsp. aizawai-treated plots. Based on these results, B. thuringiensis is a promising component for integrated pest management strategies against M. vitrata on yard-long bean in Thailand.

Mapping quantitative trait loci for yield-related traits in soybean (Glycine max L.).

Development of soybean cultivars with high seed yield is a major focus in soybean breeding programs. This study was conducted to identify genetic loci associated with seed yield-related traits in soybean and also to clarify consistency of the detected QTLs with QTLs found by previous researchers. A population of 135 F2:3 lines was developed from a cross between a vegetable soybean line (MJ0004-6) and a landrace cultivar from Myanmar (R18500). They were evaluated in the experimental field of Kasetsart University, Kamphaeng Saen, Nakhon Pathom, Thailand in a randomized complete block design with two replications each in 2011 and 2012 growing seasons. The two parents exhibited contrasting characteristics for most of the traits that were mapped. Analysis of variance showed that the main effects of genotype and environment (year) were significant for all studied traits. Genotype by environment interaction was also highly significant for all the traits. The population was genotyped by 149 polymorphic SSR markers and the genetic map consisted of 129 SSR loci which converged into 38 linkage groups covering 1156 cM of soybean genome. There were 10 QTLs significantly associated with seed yield-related traits across two seasons with single QTLs explaining between 5.0% to 21.9% of the phenotypic variation. Three of these QTLs were detected in both years for days to flowering, days to maturity and 100 seed weight. Most of the detected QTLs in our research were consistent with earlier QTLs reported by previous researchers. However, four novel QTLs including SF1, SF2 and SF3 on linkage groups L and N for seed filling period and PN1 on linkage group D1b for pod number were identified in the present study.

Influence of colostral quality on serum proteins in dairy calves raised in smallholder farms in Thailand

The objective of this study was to analyze the influence of colostral quality on serum proteins in calves. Samples were collected from visited farms in Kasetsart University Veterinary Teaching Hospital at Kamphaeng Saen and Nong Pho Animal Hospital. In total, 35 dairy farms contributed 80 dams and calves' samples. Colostrum samples from 80 dairy cows and blood samples from their calves were taken to evaluate colostral immunoglobulins (Ig) and immunoglobulin G (IgG), and calf serum protein and IgG. Total colostral Ig, colostral and serum IgG, and serum protein were measured by a colostrometer, single radial immunodiffusion, and refractrometer, respectively. Immunoglobulin G and serum protein concentrations increased in the 1st day after birth, and maximum concentrations were seen in the 2nd day and then decreased in the 7th and 14th days. Average ± SD total colostral IgG concentrations at calving date and at 1 and 2days after calving were 93.85 ± 33.89, 37.11 ± 23.51, and 17.23 ± 9.4mg/mL, respectively. The profile of total Ig and IgG concentrations in colostrum had a similar pattern, with the maximum concentrations obtained in calving date and rapidly decreased thereafter. Low IgG concentrations were seen in the 7th and 14th day after calving. The calves that were fed with high quality colostrum had higher serum protein at 1day of age, 7.49 ± 1.01g/dL, than calves fed with low quality colostrum, 6.40 ± 0.86g/dL (P < 0.01). The increase in serum protein after first colostrum feeding of high and low quality colostrum was 1.55 ± 1.07 and 0.81 ± 0.69g/dL, respectively (P = 0.02).

Quantitative trait locus mapping reveals conservation of major and minor loci for powdery mildew resistance in four sources of resistance in mungbean [Vigna radiata (L.) Wilczek

Powdery mildew (PM) is a common and serious disease of mungbean [Vigna radiata (L.) Wilczek]. A few quantitative trait loci (QTL) for PM resistance in mungbean have been reported. The objective of this study was to locate QTL for PM resistance in two resistant accessions V4718 and RUM5. Simple sequence repeat markers were analyzed in an F2 population from a cross between Kamphaeng Saen 1 (KPS1; susceptible to PM) and V4718 (resistant to PM), and in F2 and BC1F1 populations from a cross between Chai Nat 60 (CN60; susceptible to PM) and RUM5 (resistant to PM). Progenies of 134 F2:3 and F2:4 lines derived from KPS1 × V4718, and 190 F2:3 and 74 BC1F1:2 lines derived from CN60 × RUM5 and CN60 × (CN60 × RUM5), respectively, were evaluated for response to PM under field conditions. Multiple interval mapping identified a major QTL on linkage group (LG) 9 and two minor QTL on LG4 for the resistance in V4718, and detected two major QTL on LG6 and LG9 and one minor QTL on LG4 for the resistance in RUM5. Comparative linkage analysis of the QTL for PM resistance in this study and in previous reports suggests that the resistance QTL on LG9 in V4718, RUM5, ATF3640 and VC6468-11-1A are the same locus or linked. One QTL on LG4 is the same in three sources (V4718, RUM5 and VC1210A). Another QTL on LG6 is the same in two sources (RUM5 and VC6468-11-1A). In addition, one QTL in V4718 on LG4 appears to be a new resistance locus. These different resistance loci will be useful for breeding durably PM-resistant mungbean cultivars.

Development of tetraploid plants from an interspecific hybrid between mungbean (Vigna radiata) and rice bean (Vigna umbellata)

Mungbean (Vigna radiata) and rice bean (V. umbellata) (both species 2n = 2x = 22) have desirable traits that complement each other. In this study, we rescued embryos from a cross between mungbean cv. “Kamphaeng Saen 2” and rice bean cv. “Miyazaki” and resolved the hybrid sterility problem by colchicine treatment. The interspecific hybrids were obtained when Kamphaeng Saen 2 was used as the female parent. Four out of 80 immature seeds at 12 days old were able to germinate on an MS medium supplemented with 1 mg L−1 IAA, 0.2 mg L−1 kinetin, and 500 mg L−1 casein hydrolysate. Forty random amplified polymorphic DNA (RAPD) primers were screened for polymorphism among the parents, and two specific primers were finally chosen for testing of hybridity. Using the two primers, all putative F1 hybrids were confirmed as the interspecific hybrids. To observe their fertility, some of the hybrid seedlings were transplanted. The hybrid produced flowers profusely but failed to set pods. To overcome the sterility, plants were induced to become tetraploid by colchicine treatment in vitro. The ploidy level of the regenerated seedlings was confirmed from leaf DNA using a flow cytometer. Three out of 20 hybrid seedlings (15%) were successfully induced from diploid to tetraploid by a colchicine concentration of 2 g L−1. The tetraploid hybrids were able to produce flowers and set pods normally.

Phenolic composition and antioxidant activity of white mulberry (Morus alba L.) fruits

SummaryEight major mulberry cultivars [Nakhonratchasima 60 (NS 60), Buriram 60 (BR 60), Chumphon (CP), Wavee (WV), Chaingmai (CM), Pikultong (PT), Kamphaengsaen (KS) and Kamnanchul (KJ)] cultivated in Thailand were assessed for their flavonoid and phenolic acid composition using HPLC and tested for antioxidant potential using 2,2‐diphenyl‐1‐picrylhydrazyl hydrate (DPPH) assay. The total phenolic content (TPC) ranged from 104.78 to 213.53 mg GAE/100 g DW, and total flavonoid content (TFC) ranged from 69.58 to 211.01 mg CE/100 g DW. The major flavonoid compounds in mulberry fruit cultivars were (+)‐catechin (309.26–750.01 mg/100 g DW), procyanidin B1 (62.59–224.41 mg/100 g DW), quercetin (5.36–58.42 mg/100 g DW), rutin (18.73–26.90 mg/100 g DW) and (−)‐epicatechin (8.47–29.21 mg/100 g DW). Gallic acid, cinnamic acid and p‐hydroxybenzoic acid were found to be the major phenolic acids in mulberry fruit cultivars. The gallic acid and cinnamic acid contents ranged from 7.33 to 23.90 mg/100 g DW and from 11.64 to 15.05 mg/100 g DW, respectively. p‐Hydroxybenzoic acid content ranged from 1.77 mg/100 g DW (PT) to 7.13 mg/100 g DW (KJ). DPPH‐scavenging ability was excellent for ethanolic extract of NS 60, and EC50 value of NS 60 (241.83 μg mL−1) was significantly lower than those of the others (P &lt; 0.05). TPC and TFC of the mulberry fruit were positively correlated with the DPPH‐scavenging ability.

Molecular Characterization of Begomoviruses Infecting Sauropus androgynus in Thailand

AbstractBegomoviruses were detected in leaf samples of Sauropus androgynus (L.) Merr. plants showing leaf curling with or without yellowing symptoms in Kamphaeng Saen, Nakhon Pathom, Thailand in 2009 and 2010. From eight plants with symptoms, 17 complete begomoviral DNA‐As were amplified by polymerase chain reaction and sequenced. No DNA‐B was detected in any of the plants. All the DNA‐As had the characteristic begomovirus genome organization of six open reading frames, two in the virion‐sense orientation and four in the complementary orientation. Sequence comparison of these virus isolates indicated that one isolate belongs to Tomato leaf curl New Delhi virus, 12 isolates belong to Ageratum yellow vein virus and four isolates belong to a novel species with the tentative name Sauropus leaf curl virus. Five of the eight samples were found to be co‐infected by isolates of two different begomovirus species. Recombination analysis indicated that all but one of the isolates were probably the product of one or more recombination events. The results indicated that S. androgynus plants act as natural hosts as well as potential nurseries for genetic recombination between begomovirus species and strains.

Mapping QTL conferring resistance to iron deficiency chlorosis in mungbean [Vigna radiata (L.) Wilczek

Foliar chlorosis caused by iron deficiency of plants grown on calcareous soil results in substantial crop yield loss and is an important in crop production problem. The objective of this study was to identify the quantitative trait locus (QTL) controlling resistance to iron deficiency chlorosis (IDC) in mungbean. An RIL population of 122 F8 lines developed from the cross between a susceptible cultivar, “Kamphaeng Saen 2” and a resistant line, “NM10-12” was genetically analyzed with simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers. The population was evaluated for IDC resistance in an iron deficient field by visually scoring and SPAD measurements in 2010 and 2011. Segregation of the visual scores and SPAD values of the RILs in both years suggested quantitative inheritance of the resistance to IDC. Visual score and SPAD value from each year and combined data were used for QTL analysis. Single marker analysis revealed that 12 DNA markers from 3 linkage groups (LG) associated with the resistance. Four SSR and two AFLP markers on LG 3 associated with the resistance in all cases. Composite interval mapping identified two QTLs, qIDC3.1 and qIDC2.1, controlling the resistance. qIDC3.1 on LG 3 was identified from visual scores and SPAD values to account for 12.12% and 41.67% of the total variation depending on traits measured and years. qIDC2.1 on LG 2 was detected only from visual score data in 2010 and explained 45.66% of the total variation. The qIDC3.1 was the same as qIR which was the major QTL previously reported for IDC in mungbean grown in hydroponic conditions. The SSR markers CEDG084 and CEDC031 flanked and closely linked to the qIDC are useful for marker-assisted selection for mungbean resistance to IDC.

Superovulation with Different Doses of Follicle Stimulating Hormone in Kamphaeng Saen Beef Cattle

An experiment was conducted to investigate the effect of different doses of follicle stimulating hormone (FSH) used in a superovulation program on numbers of corpora lutea, total ova/embryos and transferable embryos in Kamphaeng Saen beef cattle. Cyclic cows (n=3) and heifers (n=3) of Kamphaeng Saen beef breed were assigned to two levels of FSH (200 and 250 mg. NIH-FSH-P1) in Crossover Design by which two changes over treatments were studied over two periods in all animals. Cows and heifers were estrous synchronized by Cloprostenol (500 µg). Estrus detection was performed by teaser bull (Day 0 = day of the onset of standing estrus). On day 9 after the onset of standing estrus, all animals were treated with FSH twice daily in decreasing doses over 4 days. On day 3 of FSH injection, each animal was treated with Cloprostenol (500 µg). At the first standing estrus, all animals were artificially inseminated three times at 12 h intervals. Two straws of frozenthawed semen of Kamphaeng Saen bull were used per insemination. All animals were treated with gonadotropin releasing hormone (10 µg of Buserelin) at first insemination. Numbers of corpora lutea were determined by rectal palpation and embryos were flushed seven days after the onset of standing estrus and classified according to the development stage and quality. The results showed that numbers of corpora lutea, percentages of total ova/embryos and percentages of transferable embryos were not significantly different (P>0.05) between treatments (FSH: 200 versus 250 mg) in either cows or heifers.

Measurements of hydrogen peroxide concentrations in Tokyo and Thailand

Gas-phase hydrogen peroxide (H2O2) is very harmful to plants when combined with ozone (O3). Information on ambient H2O2 concentrations, especially for long durations, is limited not only in Thailand and South East Asia but also in Japan. The objective of the present research was to accumulate data of H2O2 concentrations over long durations in Tokyo and Thailand. Hydrogen peroxide concentrations were monitored at Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan (lat. 35.7°N long. 139.5°E), Kasetsart University, Kamphaeng Saen, Nakhon Pathom (lat. 14.0°N long. 100.0°E) and Mae-On, Chiang Mai (lat. 18.8°N long. 99.2°E), Thailand in 2009, 2010 and 2011. During the measurement period, the monthly average H2O2 concentration in Tokyo ranged from 0.0 to 2.2 ppbv, and showed lower values in May, June and November 2010 and became zero in January, February and April 2011. In Chiang Mai, the monthly average H2O2 concentration was a little higher than that of Tokyo, ranging from 1.2 to 3.1 ppbv. The monthly average H2O2 concentrations in Nakhon Pathom were three to four times higher than those of Tokyo and Chiang Mai in the same period except March and April 2011. The diurnal characteristics of H2O2 concentrations from October to December 2009 in Tokyo and Chiang Mai were similar and high around noon and low in the morning and late afternoon. Nevertheless, the pattern of diurnal characteristics in 2010 at Chiang Mai was high in the morning and gradually decreased in the afternoon and it was different from Tokyo. In the case of Nakhon Pathom, the variation was high each time. Thus, the diurnal characteristics varied from place to place and year to year. A positive correlation between atmospheric H2O2 and O3 and air temperature in Tokyo was found in the present observation.

QTL identification of flowering time at three different latitudes reveals homeologous genomic regions that control flowering in soybean

Since the genetic control of flowering time is very important in photoperiod-sensitive soybean (Glycine max (L.) Merr.), genes affecting flowering under different environment conditions have been identified and described. The objectives were to identify quantitative trait loci (QTLs) for flowering time in different latitudinal and climatic regions, and to understand how chromosomal rearrangement and genome organization contribute to flowering time in soybean. Recombinant inbred lines from a cross between late-flowering 'Jinpumkong 2' and early-flowering 'SS2-2' were used to evaluate the phenotypic data for days to flowering (DF) collected from Kamphaeng Saen, Thailand (14°01'N), Suwon, Korea (37°15'N), and Longjing, China (42°46'N). A weakly positive phenotypic correlation (r=0.36) was found between DF in Korea and Thailand; however, a strong correlation (r=0.74) was shown between Korea and China. After 178 simple sequence repeat (SSR) markers were placed on a genetic map spanning 2,551.7cM, four independent DF QTLs were identified on different chromosomes (Chrs). Among them, three QTLs on Chrs 9, 13 and 16 were either Thailand- or Korea-specific. The DF QTL on Chr 6 was identified in both Korea and China, suggesting it is less environment-sensitive. Comparative analysis of four DF QTL regions revealed a syntenic relationship between two QTLs on Chrs 6 and 13. All five duplicated gene pairs clustered in the homeologous genomic regions were found to be involved in the flowering. Identification and comparative analysis of multiple DF QTLs from different environments will facilitate the significant improvement in soybean breeding programs with respect to control of flowering time.

Mapping of quantitative trait loci controlling powdery mildew resistance in Mungbean (Vigna radiata (L.) Wilczek)

Powdery mildew disease in mungbean is caused by the fungus, Erysiphe polygoni D.C. We identified two quantitative trait loci (QTLs) controlling resistance to the disease in a RIL population of 190 F7 lines. The population was developed from the cross between a susceptible cultivar, “Kamphaeng Saen 1” and a resistant line, “VC6468-11-1A”. Reaction to the disease was evaluated for resistance in field and greenhouse conditions. Results from analysis of variance revealed that 15 SSR loci on three linkage groups (LG) associated with the resistance. Composite interval mapping consistently identified two QTLs on two LGs, qPMR-1 and qPMR-2, conferring the resistance. qPMR-1 and qPMR-2 accounted for 20.10 and 57.81% of the total variation for plant response to the disease, respectively. Comparison based on common markers used in our and previous studies suggested that qPMR-2 is possibly the same as the major QTL reported earlier using another resistant source. The SSR markers flanking and closely linked to qPMR-1 (CEDG282 and CEDG191) and qPMR-2 (MB-SSR238 and CEDG166) are useful for marker-assisted selection for mungbean resistance to powdery mildew.

Quantitative trait loci mapping of Cercospora leaf spot resistance in mungbean, Vigna radiata (L.) Wilczek

Cercospora leaf spot (CLS) caused by the fungus Cercospora canescens Illis & Martin is a serious disease in mungbean (Vigna radiata (L.) Wilczek), and disease can reduce seed yield by up to 50%. We report here for the first time quantitative trait loci (QTL) mapping for CLS resistance in mungbean. The QTL analysis was conducted using F2 (KPS1 × V4718) and BC1F1 [(KPS1 × V4718) × KPS1] populations developed from crosses between the CLS-resistant mungbean V4718 and CLS-susceptible cultivar Kamphaeng Saen 1 (KPS1). CLS resistance in F2 populations was evaluated under field conditions during the wet seasons of 2008 and 2009, and resistance in BC1F1 was evaluated under field conditions during the wet season in 2008. Seven hundred and fifty-three simple sequence repeat (SSR) markers from various legumes were used to assess polymorphism between KPS1 and V4718. Subsequently, 69 polymorphic markers were analyzed in the F2 and BC1F1 populations. The results of segregation analysis indicated that resistance to CLS is controlled by a single dominant gene, while composite interval mapping consistently identified one major QTL (qCLS) for CLS resistance on linkage group 3 in both F2 and BC1F1 populations. qCLS was located between markers CEDG117 and VR393, and accounted for 65.5–80.53% of the disease score variation depending on seasons and populations. An allele from V4718 increased the resistance. The SSR markers flanking qCLS will facilitate transferral of the CLS resistance allele from V4718 into elite mungbean cultivars.

Arthrobacter sp. strain KU001 isolated from a Thai soil degrades atrazine in the presence of inorganic nitrogen sources.

An atrazine degrading bacterium, strain KU001, was obtained from a sugarcane field at the Cane and Sugar Research and Development Center at the Kasetsart University, Kamphaeng Saen campus, Thailand. Strain KU001 had a rod-to-coccus morphological cycle during growth. Biolog carbon source analysis indicated that the isolated bacterium was Arthrobacter histidinolovorans. Sequence analysis of PCR product indicated the 16S rRNA gene in strain KU001 was 99% identical to the same region in Arthrobacter sp.. The atrazine degradation pathway in strain KU001 consists of the catabolic genes, trzN, atzB and, atzC. Strain KU001 was able to use atrazine as a sole nitrogen source for growth, and surprisingly, atrazine degradation was not inhibited in cells grown on ammonium, nitrate or urea, as compared to cells cultivated on growth-limiting nitrogen sources. During the atrazine degradation process, the supplementation of nitrate completely inhibits atrazine degradation activity in strain KU001, whereas ammonium and urea had no effect on atrazine degradation activity. The addition of strain KU001 to sterile or nonsterile soils resulted in the disappearance of atrazine at a rate that was 4 to 5-fold more than that achieved by the indigenous microbial community. The addition of citrate to soils resulted in enhanced atrazine degradation, 80% of atrazine disappeared within one day following nutrient supplementation.