Aunque el raleo es una practica comun en la region productora de manzana ( Malus x domestica Bork... more Aunque el raleo es una practica comun en la region productora de manzana ( Malus x domestica Borkh.) del estado de Chihuahua, aun es frecuente que se lleve a cabo de manera manual, tardia, poco eficiente y costosa. El raleo quimico es una practica cada vez mas comun. En manzano, el raleo de flores o frutos incrementa la calidad de los frutos y reduce la alternancia en la produccion. Para maximizar los beneficios de esta practica, se evaluo la eficiencia de los siguientes compuestos asperjados durante la floracion: acido naftalenacetico, cianamida hidrogenada, tiosulfato de amonio, bencil adenina, acido giberelico y una mezcla de cal-azufre y aceite de pescado como raleadores quimicos de flores en los cultivares Golden Delicious y RedChief Delicious. Otro tratamiento consistio en las aplicaciones de la mezcla de cal-azufre y aceite de pescado en floracion, ademas de una aspersion con acido naftalenacetico en post-floracion. Los resultados se compararon con un testigo con un raleo manual tardio y un tratamiento con raleo manual en floracion. En ambos cultivares, el tratamiento de cal-azufre en floracion y acido naftalenacetico en post-floracion, redujo significativamente el cuajado de frutos sin reducir el rendimiento a cosecha. Ademas, con este mismo tratamiento se obtuvieron los frutos de mayor tamano a la cosecha. Los tratamientos con cal-azufre y aceite de pescado provocaron roseteado en los frutos ‘Golden Delicious’. El tratamiento con acido naftalenacetico en floracion redujo significativamente la alternancia de la produccion observada en ‘Golden Delicious’
approved: v^ _ ^ Porter B. Lombard Several pollinizers were evaluated for phenology, fruit set, p... more approved: v^ _ ^ Porter B. Lombard Several pollinizers were evaluated for phenology, fruit set, pollen tube growth, comparative flower characteristics, and bee behavior for Royal Ann sweet cherry in the Willamette Valley during 1982 and 1983. Fruit set of hand-pollinated flowers on uncaged limbs were used to test the fertility of the cultivars evaluated. Handpollination to evaluate pollen tube growth was made on stigmas and the branches were placed in controlled temperature rooms or on caged limbs in the field. Pollen tubes were scanned in the microscope under fluorescent light with aniline blue as a dye. Field observations were used to determine the floral characteristics and bee behavior. Length of stamens and pistil, amount of pollen , sugar content in nectar, phenology of bloom period and bee attractiveness were determined. Number of bee visits per flower, and the type of bee and their behavior when foraging the different pollinizers were also evaluated. Among the cultivars eval...
Antagonistic Trichoderma spp. are used throughout the world for the biological control of soil-bo... more Antagonistic Trichoderma spp. are used throughout the world for the biological control of soil-borne plant diseases. This approach has stimulated an on-going search for more efficient mycoparasitic strains with a high potential for producing extracellular lytic enzymes. This study compares the production of lytic enzymes by native strains of Trichoderma asperellum and Trichoderma longibrachiatum on substrates of differing complexity. The quantity of protein induced by Agaricus bisporus-based medium was higher than that induced by Phymatotrichopsis omnivora-based medium. In P. omnivora medium, T. asperellum exhibited higher chitinolytic and β-1,3-glucanolytic activities than T. longibrachiatum. The enzyme profile was related to the previously reported ability of these strains to inhibit the growth of several soil-borne plant pathogens. NAGase production was similar among the tested indigenous strains of T. longibrachiatum; T479 and T359 produced more endochitinase, T479 produced more glucanase, and T341 and T359 produced more β-1,3-glucanase. The detected variations in glucanase and β-1,3-glucanase activities suggest that the production of these enzymes is strongly influenced by the substrate. Strains T397 and T359 exhibited xylanase activity, which triggers defence mechanisms in plants. Thus, these strains may utilise an additional mechanism of biocontrol.
Three Candida oleophila strains (L06, L07 smooth, and L07 rough) were evaluated in vivo and in vi... more Three Candida oleophila strains (L06, L07 smooth, and L07 rough) were evaluated in vivo and in vitro as biocontrol agents against Penicillium expansum on postharvest ‘Golden Delicious’ apples (Malus domestica Borkh.) in Chihuahua, Mexico. The in vivo and in vitro activity of exo-β-1,3-glucanase was measured as a possible biocontrol mode of action for C. oleophila. Mean disease incidence caused by P. expansum was 0.3% for apples treated with fludioxonil + ciprodinil, which were used as a positive control, and 1% for fruits treated with a combination of the three C. oleophila strains; the effects of these treatments were significantly equivalent. Disease incidence in control apples was 39% and was significantly different from the other treatments. The in vivo exo-β-1,3-glucanase activity began at 24 h and peaked at 72 and 96 h for all treatments. Strain L06 had the highest activity (7.96 nKat) and a specific activity of 2.92 nKat μg-1. Candida albicans had the lowest activity (2.83 nKat) and a specific activity of 0.67 nKat μg-1. The highest in vitro activity was for C. albicans (85.03 nKat) and the lowest for strain L06 (78.2 nKat). Significant differences in both in vivo and in vitro enzymatic activity were observed between strain L06 and C. albicans. Polynomial regression analysis (R2 = 0.96 in vitro and 0.68 in vivo) indicated that increased enzymatic activity was associated with reduced fruit disease incidence. The production of exo-β-1,3-glucanase by C. oleophila is a possible mode of action for the efficient biocontrol of P. expansum on postharvest apples.
Aunque el raleo es una practica comun en la region productora de manzana ( Malus x domestica Bork... more Aunque el raleo es una practica comun en la region productora de manzana ( Malus x domestica Borkh.) del estado de Chihuahua, aun es frecuente que se lleve a cabo de manera manual, tardia, poco eficiente y costosa. El raleo quimico es una practica cada vez mas comun. En manzano, el raleo de flores o frutos incrementa la calidad de los frutos y reduce la alternancia en la produccion. Para maximizar los beneficios de esta practica, se evaluo la eficiencia de los siguientes compuestos asperjados durante la floracion: acido naftalenacetico, cianamida hidrogenada, tiosulfato de amonio, bencil adenina, acido giberelico y una mezcla de cal-azufre y aceite de pescado como raleadores quimicos de flores en los cultivares Golden Delicious y RedChief Delicious. Otro tratamiento consistio en las aplicaciones de la mezcla de cal-azufre y aceite de pescado en floracion, ademas de una aspersion con acido naftalenacetico en post-floracion. Los resultados se compararon con un testigo con un raleo manual tardio y un tratamiento con raleo manual en floracion. En ambos cultivares, el tratamiento de cal-azufre en floracion y acido naftalenacetico en post-floracion, redujo significativamente el cuajado de frutos sin reducir el rendimiento a cosecha. Ademas, con este mismo tratamiento se obtuvieron los frutos de mayor tamano a la cosecha. Los tratamientos con cal-azufre y aceite de pescado provocaron roseteado en los frutos ‘Golden Delicious’. El tratamiento con acido naftalenacetico en floracion redujo significativamente la alternancia de la produccion observada en ‘Golden Delicious’
approved: v^ _ ^ Porter B. Lombard Several pollinizers were evaluated for phenology, fruit set, p... more approved: v^ _ ^ Porter B. Lombard Several pollinizers were evaluated for phenology, fruit set, pollen tube growth, comparative flower characteristics, and bee behavior for Royal Ann sweet cherry in the Willamette Valley during 1982 and 1983. Fruit set of hand-pollinated flowers on uncaged limbs were used to test the fertility of the cultivars evaluated. Handpollination to evaluate pollen tube growth was made on stigmas and the branches were placed in controlled temperature rooms or on caged limbs in the field. Pollen tubes were scanned in the microscope under fluorescent light with aniline blue as a dye. Field observations were used to determine the floral characteristics and bee behavior. Length of stamens and pistil, amount of pollen , sugar content in nectar, phenology of bloom period and bee attractiveness were determined. Number of bee visits per flower, and the type of bee and their behavior when foraging the different pollinizers were also evaluated. Among the cultivars eval...
Antagonistic Trichoderma spp. are used throughout the world for the biological control of soil-bo... more Antagonistic Trichoderma spp. are used throughout the world for the biological control of soil-borne plant diseases. This approach has stimulated an on-going search for more efficient mycoparasitic strains with a high potential for producing extracellular lytic enzymes. This study compares the production of lytic enzymes by native strains of Trichoderma asperellum and Trichoderma longibrachiatum on substrates of differing complexity. The quantity of protein induced by Agaricus bisporus-based medium was higher than that induced by Phymatotrichopsis omnivora-based medium. In P. omnivora medium, T. asperellum exhibited higher chitinolytic and β-1,3-glucanolytic activities than T. longibrachiatum. The enzyme profile was related to the previously reported ability of these strains to inhibit the growth of several soil-borne plant pathogens. NAGase production was similar among the tested indigenous strains of T. longibrachiatum; T479 and T359 produced more endochitinase, T479 produced more glucanase, and T341 and T359 produced more β-1,3-glucanase. The detected variations in glucanase and β-1,3-glucanase activities suggest that the production of these enzymes is strongly influenced by the substrate. Strains T397 and T359 exhibited xylanase activity, which triggers defence mechanisms in plants. Thus, these strains may utilise an additional mechanism of biocontrol.
Three Candida oleophila strains (L06, L07 smooth, and L07 rough) were evaluated in vivo and in vi... more Three Candida oleophila strains (L06, L07 smooth, and L07 rough) were evaluated in vivo and in vitro as biocontrol agents against Penicillium expansum on postharvest ‘Golden Delicious’ apples (Malus domestica Borkh.) in Chihuahua, Mexico. The in vivo and in vitro activity of exo-β-1,3-glucanase was measured as a possible biocontrol mode of action for C. oleophila. Mean disease incidence caused by P. expansum was 0.3% for apples treated with fludioxonil + ciprodinil, which were used as a positive control, and 1% for fruits treated with a combination of the three C. oleophila strains; the effects of these treatments were significantly equivalent. Disease incidence in control apples was 39% and was significantly different from the other treatments. The in vivo exo-β-1,3-glucanase activity began at 24 h and peaked at 72 and 96 h for all treatments. Strain L06 had the highest activity (7.96 nKat) and a specific activity of 2.92 nKat μg-1. Candida albicans had the lowest activity (2.83 nKat) and a specific activity of 0.67 nKat μg-1. The highest in vitro activity was for C. albicans (85.03 nKat) and the lowest for strain L06 (78.2 nKat). Significant differences in both in vivo and in vitro enzymatic activity were observed between strain L06 and C. albicans. Polynomial regression analysis (R2 = 0.96 in vitro and 0.68 in vivo) indicated that increased enzymatic activity was associated with reduced fruit disease incidence. The production of exo-β-1,3-glucanase by C. oleophila is a possible mode of action for the efficient biocontrol of P. expansum on postharvest apples.
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