Browsing by Author "Chorbadjian, Rodrigo"

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    Cross-induction of systemic induced resistance between an insect and a fungal pathogen in Austrian pine over a fertility gradient
    (2007) Eyles, Alieta; Chorbadjian, Rodrigo; Wallis, Chris; Hansen, Robert; Cipollini, Don; Herms, Dan; Bonello, Pierluigi
    Evidence for cross-induction of systemic resistance or susceptibility in plant-fungus-herbivore interactions is mostly derived from herbaceous model systems and not perennial woody plants. Furthermore, the effects of environmental variables such as soil fertility on these tripartite interactions are generally unknown. This study examined cross-induction of systemic resistance in Pinus nigra (Austrian Pine) to infection by Sphaeropsis sapinea (a fungal pathogen), or feeding by Neodiprion sertifer (European pine sawfly), by prior induction with either S. sapinea or N. sertifer, over a fertility gradient. In a replicated 3-year study, cross-induction of systemic induced resistance (SIR) was found to be both asymmetric within a single year and variable between years. Prior induction with insect defoliation induced SIR to subsequent fungal challenge in 2006 but not in 2005. In 2005, a fertility-independent negative systemic effect of the fungal infection on herbivore growth was detected while herbivore survival was affected by a significant interaction between induction treatment and fertility level in 2006. Prior infection by the fungus induced SIR against the same fungus in both years regardless of fertility levels. This is the first report of whole-plant SIR against a defoliating insect induced by a fungal pathogen and vice versa, under variable nutrient availability, in a conifer or any other tree.
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    Seeds Yield and Quality of Quinoa ( Chenopodium quinoa Willd.) Plants Grown Under Different Nitrogen Fertilization Doses
    (2024) Contreras, Samuel; Molina, Jorge; Garcia, Margarita; Sanchez, Javier; Chorbadjian, Rodrigo; Fuentes, Francisco; Albornoz, Francisco
    S. Contreras, J. Molina, M. Garc & iacute;a, J. S & aacute;nchez, R. Chorbadjian, F. Fuentes, and F. Albornoz. 2024. Seeds Yield and Quality of Quinoa (Chenopodium quinoa Willd.) Plants Grown Under Different Nitrogen Fertilization Doses. Int. J. Agric. Nat. Resour. 68-74. Quinoa ( Chenopodium quinoa Willd.) has been cultivated for more than 7,000 years in the mountain regions (Andes Mountains) of South America. Five ecotypes differing in their phenology, morphology and stress resistance can be found. One of these ecotypes corresponds to the coastal ecotype, which is cultivated mainly in Chile. Little information is available regarding the response of this ecotype to nitrogen (N) fertilization. In the present study, three N fertilization doses (low: 30, adequate: 140 and high: 280 kg ha -1 ) were evaluated in plants grown in containers. Seed yield and quality attributes, including seed weight, nitrate content, germination, and seed longevity, were evaluated. These results indicate that increasing N fertilization promotes increases in seed yield and weight. In terms of seed quality, although the fertilization treatments did not affect germination, seed longevity was reduced by increasing the N fertilization dose.