Dry matter accumulation in grain sorghum

• Autor(a) principal: Bueno, Álvaro
• Data de Publicação: 2014
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/17066
• topic: Sorghum bicolor L. Moench; growth analysis; photosynthesis; plant development; Sorghum bicolor L. Moench; análise de crescimento; fotossíntese; desenvolvimento vegetal

Results from growth analysis in grain sorghum (Sorghum bicolor L. Moench) experiments, containing a certain range of genotypes and environmental conditions, were examined from early vegetative stages until completion of plant growth. The average relative growth rate (RGR) decreased during vegetative and flowering phases and increased during the grain filling stage. The average net assimilation rate (NAR) was influeced by external factors which affect the photosynthesis and also by an internal regulatory process that controls the quantity of photosyntesized material. When the demand was high, photosynthesis and NAR were also high. But, during periods of low energy utilization both photosynthesis and NAR showed low values NAR values were significantly higher at the low density due to less leaf shading. The tall hybrid presented higher NAR values only during the vegetative phase. Variations in density and height of hybrids caused a greater impact than variations in spacings, in the average leaf area rate LAR. Conditions that promoted high values were associated with low NAR values due to more leaf shading and a consequent low photosynthetic efficiency. It was evident that materials photosynthesized before the flowering stage and stored in the stem were translocated again to the panicle during the period of grain development.