Resumen de Irrigated rice behaviour in function of seedling proportions originated from high and low physiological quality seeds

Paulo Melo, Luis Osmar Braga Schuch, Francisco Neto de Assis, Germani Concenço

• The objective of this study was to evaluate the behaviour of plant populations submitted to different proportions of seedlings originated from low and high physiological quality seeds. The trial was conducted at Universidade Federal de Pelotas, Pelotas/RS, Brazil, with five treatments (0, 25, 33, 50 and 100% of high vigor seeds in the mix). The seeds were sowed under controlled environment and transplanted to field 15 days after sowing, in order to secure the sowing stand and uniformity. The physiological parameters relative growing rate (TCR), leaf area index (IAF), crop growing rate (TCC), net assimilation rate (TAL) and absolute growing rate (TCA) were evaluated using the intervalar method between 60 – 102 and 102 – 134 days after transplanting (DAT) to field. Plant height, dry mass and tillering were evaluated at 60, 102 and 134 DAT, besides the number of panicles per plant, biological yield and grain yield were evaluated at 134 DAT. Increasing in proportion of plants from high vigor seeds, in the rice plants establishment showed reductions in physiological parameters after 60 DAT, increasing in IAF, dry matter production, and grain yield around 20% higher than plants from low vigor seeds. Key words: Oryza sativa, vigor, grain yield.