Growth and yield characteristics of Manaw Thu Kha, a Myanmar rice [Oryza sativa] cultivar, influenced by the kind of chemical fertilizer and its application method

The growth and yield of Manaw Thu Kha (MTK), a high yielding rice cultivar in Myanmar, were studied comparison with those of Japanese cultivars, Koshihikari (KH) and Nipponbare (NB). Four fertilization plots M1, M2. J1 and J2, were set in the field of Mie University and the study was conducted from 2001 to 2003. The M1 plot was top-dressed with urea of 11.4kg N/10a in total, at 30 and 60 days after transplanting (DAT) without basal dressing. The M2 plot was fertilized in the same way as in the M1 plot but with additional application of 2.2kg/10a of P2O5 at 60 DAT. The J1 plot was supplied with compound fertilizer at 6kg N/10a as basal dressing and top-dressed two times each with 2.5kg N/10a. The J2 plot was supplied with half amount of fertilizer used for the J1 plot. The plant length in M plots (M1 and M2 plots) increased rapidly for 10 days after topdressing with urea. Tillering of all the cultivars in M plots was later than that in J plots (J1 and J2 plots). The maximum tiller number of MTK was lower in the J2 plot but nearly the same in M and J1 plots. On the other hand, the maximum tiller number of KH and NB was higher in J plots than in M plots. Leaf color value of the 13th to 14th leaves from the base on the main culm was lower in MTK than in KH and NB both in M and J plots. The SPAD value of the 14th leaf of MTK rapidly decreased from the 5th week after topdressing, but that of NB remained nearly constant even after the 6th week after topdressing. The heading period of MTK was longer than that of KH and NB in both M and J plots showing two peaks of heading. The leaf area index and light extinction coefficient at heading was higher in MTK than in NB. Thus, light-interception characteristic of MTK was inferior to that of NB. In MTK, the number of panicles was greater in the Ml plot than in the M2 plot, but the number of grains per panicle and filled grain percentage were higher in the M2 plot than in the M1 plot.