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sur le développement des zones arides et semi-arides

Titre : Efeitos diferenciais da fertilização azotada sobre variedades antigas e modernas de Trigo

Auteur : Baía, Carina Roxo

Université de soutenance : Universidade de Tras os Montes E Alto Douro

Grade : Mestrado em Biotecnologia e Qualidade Alimentar 2018

Résumé partiel
Modern agriculture relies on the use of large quantities of inputs, such as nitrogen fertilizers, which results in significant costs for producers and a high environmental impact. In this way, the future of agriculture goes through the search for plant production systems that maintain high levels of productivity with quality, reducing the use of inputs. The present work is part of the AGRISOST (sistemas agrarios sostenibles. manejo de carbono, nitrógeno y agua para optimizar producción y calidad, 2014-2018). Considering that N represents a mineral nutrient essential to the development and yield of plants, in this project is intended to study the mechanisms that control the response of wheat to the application of nitrogen fertilizer and to select of varieties more efficient in the use of N. In this work, two modern varieties (Artur Nick and Califa Sur) and two old varieties (Aragón 03 and Chamorro) were studied, because genetic standardization that characterizes modern varieties may result in the loss of efficient response alleles to the use of N, which is thought to be found in older varieties characterized by a high genetic diversity. In order to fulfill the work’s objectives, were evaluated the response of morphological characteristics, phenology variables, yield and parameters related to baking quality and the rheological properties of the flour in three different nitrogen regimes (N0 – without N, N50 - 130 kg N/ha e N100 - 260 kg N/ha). In addition to the study of the agro-morphological characteristics, a PCR process was also optimized for the sequencing of glutamine synthetase, a key enzyme in N metabolism, which in several studies has been related to components of the yield of various cereals. Modern varieties showed inferior height and superior precocity in relation to the old varieties. Artur Nick was the most productive variety, Chamorro, the variety with the highest protein content and Califa Sur, the variety with the highest mixing time of the dough. Differentiated fertilization did not have a significant effect on the variables under study except for the plant height and spike density, on the contrary all variables, except for the density of spikes, showed influence of the genotype.

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