Adaptabilidade, estabilidade e variabilidade do quociente fototermal para a cultura do trigo no Estado do Paraná

Wheat (Triticum aestivum L.) is broadly cultivated in South Region of Brazil where 90% of national production of this cereal stands. However, large climate variability occurs within different wheat areas that compromise grain yield. Thus, good stability and high yield of cultivars sowed in different...

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Autor principal: Silva, Raphael Rossi
Formato: Dissertação
Idioma: Português
Publicado em: Universidade Tecnológica Federal do Paraná 2012
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Acesso em linha: http://repositorio.utfpr.edu.br/jspui/handle/1/261
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Resumo: Wheat (Triticum aestivum L.) is broadly cultivated in South Region of Brazil where 90% of national production of this cereal stands. However, large climate variability occurs within different wheat areas that compromise grain yield. Thus, good stability and high yield of cultivars sowed in different locations is very important. The objective of this work was to perform a review to expose the qualities of AMMI and GGE Biplot methodologies and, later, to evaluate the adaptability and stability of wheat cultivars, submitted to different seasons of sowing at Guarapuava and Palotina locations, and identify the best sowing season for each. Also, this work aimed to study the time and space variability of photothermal quotient, the occurrence of hoarfrost and discuss the impact of these variables to define the adequate sowing season for wheat at Parana State. Literature review indicates that AMMI methodology presents the best efficiency when the potential of grain yield at the environment is to be inferred, and the AMMI1 model is recommended. However, when the objective of the researcher is strictly to select superior genotypes that present high yield and productive stability, the GGE biplot model is more efficient, mainly, due to the presence of main effect of PC1 in genotype (principal component 1). Also, GGE biplot methodology is indicated in studies for mega environments definition, in order to identify environmental groups. Late sowings in Guarapuava and advanced sowings in Palotina presented higher grain yield when cultivars were evaluated in different sowing seasons. BRS Umbu cultivar (Guarapuava) presented specific adaptation to E1, considered an unfavorable environmental condition. On the other hand, Safira cultivar presented high adaptability, stability and high grain yield. Therefore, it was concluded that in different and not representative seasons as, for example E1 (Guarapuava), adapted cultivars to this environmental condition present specific adaptability, while when in different and representative seasons as, for example E3 (Palotina), adapted cultivars present high adaptability. The highest values for the variability study of photothermal quotient were observed in VCU1 region (cold, humid and high altitude) however the probability of hoarfrost occurrence was high. In a broader sense, VCU3 region (hot, moderately dry and low altitude) presented the lower values of photothermal quotient. Wheat sowing in Parana must be performed at first in VCU3 region (10/03 to 10/05) followed by VCU2 region (20/03 to 10/06) and for last in VCU1 region (20/06 to 20/07). Based on photothermal quotient, it was concluded that VCU1 region is the one that may present higher potential for grain yield.