Received: 21-03-2013 / Accepted: 26-04-2013
The pot-experiment was carried out in the green house at the Faculty of Agronomy in autumn 2011 and spring season 2012 to evaluate photosynthetic characteristics, dry matter accumulation and plant growth rate of short - growth duration rice genotypes. Two lines, IL 3-4-2-7, IL 19-4-3-8 and control varierty IR24 were used in this study. At active tillering, heading and dough ripening stages, four plants of each line were randomly selected to measure photosynthetic characteristics, such as photosynthetic rate, SPAD value (an indicator of chlorophyll content), leaf area and dry matter biomass in leaves, stems and panicles. The results showed that there was no significant difference in photosynthetic characteristics and dry matter production between IL-lines and IR24. Plant growth rate (PGR) of IL3-4-2-7 and IL 19-4-3-8 from active tillering to heading stages was higher than that from heading to dough ripening stage. In contrary, the PGR of IR24 was the same at two stages. A significant and positive correlation between grain yield and photosynthesis rate at active tillering and heading stages was found in newly selected lines, whereas the significant and positive correlation between grain yield and photosynthesis rate at heading and dough ripening periods was observed for IR24 variery. Grain yield of lines with short growth duration correlated significantly and positively with PGR before heading stage, while grain yield of IR24 correlated significantly and positively with PGR after heading stage.
