Eficiência nutricional em fósforo de genótipos de cana-de-açúcar

• Autor(a) principal: Silveira, Gustavo da
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1375
• topic: Saccharum spp.; Eficiência de absorção; Eficiência de utilização; Sistema radical; Saccharum spp.; Absorption efficiency; Utilization efficiency; Radical system; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL

Low P availability is one of the major factors limiting crop production in tropical areas. Phosphate fertilizer application is the conventional method to alleviate P deficiency in the soil, but it is often inefficient because the P supplied can bind to soil particles and become unavailable to plants. Therefore, the improvement of P efficiency in crops would be more efficient, less expensive and environmentally safer. This work was developed considering these and involved two experiments. First, we attempted to identify genetic variability in sugarcane for P efficiency, taking into account P acquisition efficiency (PAE) and P utilization efficiency (PUE). Twenty-three sugarcane genotypes were cultivated in a greenhouse in 30 L pots with two P levels, high-P and low-P, for eight months. It was possible to identify genetic variation for PAE and PUE and measure the genotypes performance as affected by these traits. In low P availability, PAE was more effective in discriminating among the genotypes. However, PUE was more effective in high P availability. The second experiment aimed to identify morphological and physiological sugarcane traits related to P-efficiency and was conducted in a greenhouse for three months. Nineteen sugarcane genotypes were cultivated in 9 L pots with two P levels, high-P and low-P. The measured traits were: leaf area, shoot and root dry weight, root length of three classes of roots, root hair, and photosynthetic rate. Genetic variation was detected for all traits. The traits had different effects on performance at high-P or low-P. Fine roots and leaf area were correlated with increased sugarcane performance in the low P condition. We concluded that there is genetic variation in sugarcane for P efficiency. Therefore, it is possible to select genotypes with increased phosphorus acquisition in low P soils, and increased phosphorus utilization efficiency in high P soils. Root traits, especially, may increase P efficiency.