2.2. Agronomic traits measurements
For agronomic analyses, all the tested rice accessions were
grown on the experimental farm of the Taiwan Agricultural
Research Institute in autumn 2009, spring and autumn 2010, and
spring 2011. Rice grains were sown in the nursery plots, where the
seedlings grew up to the three-leaf stage before transplanting. The
seedlings from the two autumn crops were transplanted to the
experimental plots on 5 August 2009 and 30 July 2010, respectively.
The seedlings from the two spring crops were transplanted to the
experimental plots on 5 February 2010 and 16 February 2011,
respectively. The experiment was laid out in a completely
randomized block design with four replicates. One seedling per hill
was planted with a spacing of 30 cm 15 cm in each experimental
plot of 3m 6 m. Each plot received a basal application of fertilizer
before transplanting (24 kg N ha1, 36 kg P2O5 ha1 and
24 kg K2O ha1) and three top-dressings of fertilizer on the 20th
day (6 kg N ha1, 9 kg P2O5 ha1 and 6 kg K2O ha1), the 40th day
(9 kg N ha1, 13.5 kg P2O5 ha1 and 9 kg K2O ha1) and the 60th day
(9 kg N ha1, 13.5 kg P2O5 ha1 and 9 kg K2O ha1) after transplanting.
Diseases and pests were controlled using the standard
practices in the study areas. The middle four rows (2min length) of
each plot were hand-harvested. The grain mass of those handharvested
samples was weighed, and the moisture content of
each sample was also measured. Yields were expressed at
140 g kg1 moisture.