Sampling and PCR method for detecting pathogenic Fusarium oxysporum strains in onion harvest

Fusarium basal rot is a worldwide disease problem in onions, and causes substantial losses in onion production, both during the growing season and in the storage. To minimize the post-harvest losses, a protocol for screening of latent infections with pathogenic Fusarium oxysporum strains from harvested onions was developed. This protocol is based on a dual PCR test with primers specific for the fungal species and new SIX3 primers specific for the onion-pathogenic F. oxysporum strains. A pooled sample containing pieces from 50 harvested symptomless onions was prepared for the dual PCR using microwave disruption of the filamentous Fusarium fungi and Whatman FTA(TM) filter paper matrix technology, or as a reference protocol, by extracting DNA with a commercial kit. The two sample preparation protocols gave consistent results with the tested onion samples. Detection limit of the dual PCR protocol was 100 pg of F. oxysporum DNA, in a mixture with onion DNA, when the FTA card was applied. The new protocol reported here is simple and sensitive enough for routine testing, enabling the detection of latent infections in harvest lots even at the infection levels under 10%. Significance and Impact of the Study Fusarium basal rot causes serious problems in onion production. To minimize post-harvest losses, a simple protocol based on FTA(TM) technology and a dual PCR test with Fusarium oxysporum species-specific and pathogenicity-specific primers was developed. By testing pooled onion samples using this method, latent infections with F. oxysporum can be screened from a representative sample of the harvest. This screening method could be a useful tool to manage the post-harvest losses caused by latent infections with F. oxysporum and, with modification of the PCR protocol, with other Fusarium species pathogenic to onion.Peer reviewe

Addition of meloxicam to the treatment of clinical mastitis improves subsequent reproductive performance

AbstractA blinded, negative controlled, randomized intervention study was undertaken to test the hypothesis that addition of meloxicam, a nonsteroidal anti-inflammatory drug, to antimicrobial treatment of mild to moderate clinical mastitis would improve fertility and reduce the risk of removal from the herd. Cows (n=509) from 61 herds in 8 regions (sites) in 6 European countries were enrolled. Following herd-owner diagnosis of mild to moderate clinical mastitis within the first 120d of lactation in a single gland, the rectal temperature, milk appearance, and California Mastitis Test score were assessed. Cows were randomly assigned within each site to be treated either with meloxicam or a placebo (control). All cows were additionally treated with 1 to 4 intramammary infusions of cephalexin and kanamycin at 24-h intervals. Prior to treatment and at 14 and 21d posttreatment, milk samples were collected for bacteriology and somatic cell count. Cows were bred by artificial insemination and pregnancy status was subsequently defined. General estimating equations were used to determine the effect of treatment (meloxicam versus control) on bacteriological cure, somatic cell count, the probability of being inseminated by 21d after the voluntary waiting period, the probability of conception to first artificial insemination, the number of artificial insemination/conception, the probability of pregnancy by 120 or 200d postcalving, and the risk of removal by 300d after treatment. Cox’s proportional hazards models were used to test the effect of treatment on the calving to first insemination and calving to conception intervals. Groups did not differ in terms of age, clot score, California Mastitis Test score, rectal temperature, number of antimicrobial treatments given or bacteria present at the time of enrollment, but cows treated with meloxicam had greater days in milk at enrollment. Cows treated with meloxicam had a higher bacteriological cure proportion than those treated with the placebo [0.66 (standard error=0.04) versus 0.50 (standard error=0.06), respectively], although the proportion of glands from which no bacteria were isolated posttreatment did not differ between groups. No difference was observed in the somatic cell count between groups pre- or posttreatment. The proportion of cows that underwent artificial insemination by 21d after the voluntary waiting period was unaffected by treatment. Treatment with meloxicam was associated with a higher proportion of cows conceiving to their first artificial insemination (0.31 versus 0.21), and a higher proportion of meloxicam-treated cows were pregnant by 120d after calving (0.40 versus 0.31). The number of artificial inseminations required to achieve conception was lower in the meloxicam compared with control cows (2.43 versus 2.92). No difference was observed between groups in the proportion of cows pregnant by 200d after calving or in the proportion of cows that were culled, died, or sold by 300d after calving (17% versus 21% for meloxicam versus control, respectively). It was concluded that use of meloxicam, in conjunction with antimicrobial therapy, for mild to moderate cases of clinical mastitis, resulted in a higher probability of bacteriological cure, an increased probability of conception to first artificial insemination, fewer artificial inseminations, and a greater proportion of cows pregnant by 120d in milk

Acute phase response in two consecutive experimentally induced E. coli intramammary infections in dairy cows

<p>Abstract</p> <p>Background</p> <p>Acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) have suggested to be suitable inflammatory markers for bovine mastitis. The aim of the study was to investigate acute phase markers along with clinical parameters in two consecutive intramammary challenges with <it>Escherichia coli </it>and to evaluate the possible carry-over effect when same animals are used in an experimental model.</p> <p>Methods</p> <p>Mastitis was induced with a dose of 1500 cfu of <it>E. coli </it>in one quarter of six cows and inoculation repeated in another quarter after an interval of 14 days. Concentrations of acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) were determined in serum and milk.</p> <p>Results</p> <p>In both challenges all cows became infected and developed clinical mastitis within 12 hours of inoculation. Clinical disease and acute phase response was generally milder in the second challenge. Concentrations of SAA in milk started to increase 12 hours after inoculation and peaked at 60 hours after the first challenge and at 44 hours after the second challenge. Concentrations of SAA in serum increased more slowly and peaked at the same times as in milk; concentrations in serum were about one third of those in milk. Hp started to increase in milk similarly and peaked at 36–44 hours. In serum, the concentration of Hp peaked at 60–68 hours and was twice as high as in milk. LBP concentrations in milk and serum started to increase after 12 hours and peaked at 36 hours, being higher in milk. The concentrations of acute phase proteins in serum and milk in the <it>E. coli </it>infection model were much higher than those recorded in experiments using Gram-positive pathogens, indicating the severe inflammation induced by <it>E. coli</it>.</p> <p>Conclusion</p> <p>Acute phase proteins would be useful parameters as mastitis indicators and to assess the severity of mastitis. If repeated experimental intramammary induction of the same animals with <it>E. coli </it>is used in cross-over studies, the interval between challenges should be longer than 2 weeks, due to the carry-over effect from the first infection.</p

Effect of harvest time on storage loss and sprouting in onion

Storability of onion is affected by timing of harvest. However, the optimal time for maximum yield and maximum storability do not necessarily coincide. This study aimed to determine the most suitable harvest time for obtaining a high bulb yield with high quality and storability. Storage experiments were conducted on onions produced in field experiments at a research field and on farms in four years. Results indicate that harvesting could be delayed to 100% maturity, or even longer, without a marked increase in storage loss. In rainy years, late harvest is likely to impair the quality. The incidence of sprouting in shelf life tests varied considerably between years. An early harvest before 50% maturity and a delayed harvest increased the risk of sprouting. It may be concluded that the harvesting of onions for long-term storage can be timed to take place between 50% maturity and even some weeks after complete maturity without a loss in storage quality. Therefore, it is possible to combine high yield and good storage quality.Sadonkorjuuaika vaikuttaa sipulin varastokestävyyteen. Korjuuoptimi ei kuitenkaan ole välttämättä sama tavoiteltaessa korkeaa satoa tai hyvää säilyvyyttä. Tämän tutkimuksen tavoitteena oli määrittää suotuisin sadonkorjuuaika, kun päämääränä on sekä määrältään että varastolaadultaan hyvä sato. Neljänä vuonna tehdyissä varastointikokeissa käytettiin puutarhatuotannon tutkimusyksikössä ja eteläsuomalaisilla tiloilla viljeltyä satoa. Tulosten mukaan sadonkorjuuta voidaan lykätä 100 %:n tuleentumiseen asti, ja jopa pidempään, ilman varastohävikin merkittävää lisääntymistä. Sateisina vuosina myöhäinen korjuu kuitenkin saattaa heikentää laatua. Sipuleiden versomisalttius vaihteli huomattavasti vuosittain. Varhainen, ennen 50 %:n tuleentumisastetta ajoitettu sadonkorjuu ja viivästetty korjuu lisäsivät versomisriskiä. Tutkimuksen mukaan pitkäaikaiseen varastointiin tarkoitettu sipuli voidaan korjata 50 %:n ja 100 %:n tuleentumisasteen välillä, jopa pari viikkoa täyden tuleentumisen jälkeen varastolaadun heikkenemättä. Näin ollen on mahdollista saavuttaa yhtä aikaa korkea sato ja hyvä varastokestävyys

Growth of and partitioning between shoot and storage root of carrot in a northern climate

Matching the growth pattern of a vegetable cultivar with the seasonal changes in climate is a prerequisite for successful yield production in a northern climate. This paper describes the growth characteristics of two carrot cultivars in relation to climatic conditions in two years, with special reference to the factors associated with high yield. Cv. Fontana produced twice as large a leaf area and shoot weight as cv. Panther. Increased partitioning to shoot in the former cultivar also resulted in a higher root yield. Uniformity in relative growth rates during the period of analysis suggests that intervarietal differences in the shoot to root ratio and in the yield potential appear very early. Nearly half of the root weight at final harvest was gained after mid-August, when temperature and daily irradiance began to decrease. A large leaf area may ensure better utilisation of diminishing growth resources at the end of the growing season. In the more favourable growing season, 1997, plants invested more in leaf production than they did in 1996: shoot fresh and dry weights were considerably higher but leaf area was not much higher.;Vihanneslajikkeiden kasvurytmin oikea ajoittuminen suhteessa ympäristötekijöiden muutoksiin on sadontuotannon edellytys pohjoisissa oloissa. Tässä tutkimuksessa kuvataan kahden porkkanalajikkeen kasvua suhteessa säätekijöihin kahtenakoevuonna, erityistavoitteena arvioida satopotentiaalia sääteleviä kasvumuuttujia. Fontana-lajike tuotti kaksinkertaisen lehtialan ja lehtimassan Panther-lajikkeeseen verrattuna. Suurempi lehtimassa ja -ala edesauttoivat myös suuren juurisadon muodostumista. Molempien lajikkeiden suhteellisten kasvunopeuksien yhtäsuuruus kasvukaudella merkitsee, että lajikkeiden väliset erot verso/juuri -suhteessa ja satopotentiaalissa syntyvät hyvin aikaisin. Lähes puolet varastojuurten painosta syntyi elokuun puolivälin jälkeen, jolloin lämpötila ja säteily alkoivat selvästi vähetä. Suuri lehtiala varmistanee vähenevien kasvutekijöiden tehokkaamman hyväksikäytön kasvukauden lopulla. Sääoloiltaan suotuisampana kasvukautena 1997 kasvit sijoittivat yhteyttämistuotteitaan enemmän lehtien tuotantoon kuin vuonna 1996: lehtien tuore- ja kuivapainot olivat selvästi korkeammat, mutta lehtiala ei paljon vaihdellut eri vuosina

Effects of fertilisation and irrigation practices on yield, maturity and storability of onions

The study aimed to establish whether a high onion yield and good storage performance could be obtained with low fertilisation rates if irrigation was applied when necessary. Two-year experiments investigated the effects of three NPK fertiliser levels (N 50, 100, 125/150 kg/ha), with and without irrigation, on yield, advancement of maturity, storage losses and shelf life. High fertilisation advanced maturity but irrigation had no effect. High fertilisation increased yield only in 1996 (5B7%), but irrigation increased the yield noticeably: by 33.5% in 1995 and 8.5% in 1996. There was no interaction between fertilisation and irrigation. The low fertilisation optimum is attributed to the mineralisation of soil nitrogen, as the soil was rich in organic matter. At the low fertilisation level, plants took up twice as much nitrogen as present in the fertiliser, and with increased fertilisation the nitrogen uptake increased markedly. The foliage nitrogen content was low, evidently as a result of late harvesting. Treatments had only a minor effect on the storage performance and shelf life of onions. The results suggest that fertilisation rates could be reduced in onion production. Irrigation during warm and dry periods is essential to achieve the maximum yield potential and does not impair the storage quality of onions.;Tutkimuksen tavoitteena oli selvittää, voidaanko määrältään ja varastokestävyydeltään hyvä sipulisato saavuttaa vähällä lannoituksella, kun kasvustoa kastellaan tarvittaessa. Kaksivuotisissa kokeissa tutkittiin kolmen lannoitusmäärän (N 50, 100, 125/150 kg/ha) ja kastelun vaikutusta sadon määrään, valmistumiseen sekä varasto- ja kauppakestävyyteen. Sadon valmistuminen nopeutui lannoitusta lisättäessä, mutta kastelu ei vaikuttanut tuleentumiseen. Runsas lannoitus lisäsi satoa vain vuonna 1996 (5B7 %). Sen sijaan kastelu lisäsi satoa selvästi: 33,5 % vuonna 1995 ja 8,5 % vuonna 1996. Kastelun ja lannoituksen välillä ei havaittu yhdysvaikutusta. Alhaisen lannoitusoptimin oletetaan johtuvan typen mineralisoitumisesta maassa. Pienimmällä lannoitustasolla kasvit pystyivät ottamaan kaksinkertaisen typpimäärän lannoituksessa annettuun määrään verrattuna. Lannoituksen lisääminen lisäsi huomattavasti kasvien typenottoa. Lehtien typpipitoisuus oli pieni, minkä oletetaan johtuvan myöhäisestä sadonkorjuusta. Käsittelyiden vaikutus sipulin varasto- tai kauppakestävyyteen oli vähäinen. Tulosten mukaan sipulin lannoitusta voidaan alentaa, jolloin ravinnepäästöt ympäristöön vähenevät. Kastelu on välttämätöntä kuivien jaksojen aikana täyden sadon saamiseksi, eikä se heikennä sipuleiden varastokestävyyttä

Yield potential of chive: Effects of cultivar, plastic mulch and fertilisation

Chive is a perennial herb, growing also natural in Finland. Commercial production of the herb is very small in our country, but large amounts of chive are imported. This fact has aroused interest in investigating the opportunities of producing chive using modern cultivation techniques. Effects of cultivar, plastic mulch as ground cover and fertilisation on yield were studied in field experiments over three years. In the experiments, the most productive cultivars or populations (a Finnish population Hankoniemi, a Dutch population Tavallinen and a German cultivar Grolau) produced 1020% higher yields than the less productive cultivars. There were no clear differences in the yield quality between the cultivars. Black plastic mulch was effective in increasing yield, controlling weeds and maintaining soil moisture. For fertilisation, the experiments revealed the high nutrient demand of chive. After the basic soil fertilisation, weekly fertigation with a NPK fertiliser at a higher nitrogen dose (10-15 kg ha -1 N per week) resulted in higher biomass production than fertigation with nitrogen alone and/or a half nitrogen dose. In the years following the planting, the annual uptakes in yield were 185-200 kg ha -1 for nitrogen, 17-20 kg ha -1 for phosphorus, and 120-140 kg ha -1 for potassium in the most intensively fertilised treatment producing the highest yield. The results show that chive is feasible for commercial production with modern cultivation techniques.

Effect of harvest time on storage loss and sprouting in onion

Storability of onion is affected by timing of harvest. However, the optimal time for maximum yield and maximum storability do not necessarily coincide. This study aimed to determine the most suitable harvest time for obtaining a high bulb yield with high quality and storability. Storage experiments were conducted on onions produced in field experiments at a research field and on farms in four years. Results indicate that harvesting could be delayed to 100% maturity, or even longer, without a marked increase in storage loss. In rainy years, late harvest is likely to impair the quality. The incidence of sprouting in shelf life tests varied considerably between years. An early harvest before 50% maturity and a delayed harvest increased the risk of sprouting. It may be concluded that the harvesting of onions for long-term storage can be timed to take place between 50% maturity and even some weeks after complete maturity without a loss in storage quality. Therefore, it is possible to combine high yield and good storage quality

Sensory Quality of Carrots: Effect of Harvest and Storage Time

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