3. Experimental Section
3.1. Germplasm Characterization
A total of 307 rice germplasms conserved at the Philippine Rice Research Institute (PhilRice)
genebank which were collected from different parts of the country (Figure 4) were used to evaluate the
genetic diversity of farmers’ traditional rice varieties and landraces. Characterization of the collected
rice germplasms was done at the at the PhilRice Central Experimental Station, Maligaya, Science City
of Munoz, Nueva Ecija (15°40 N, 120°53 E, 57.6 masl) during the wet cropping season (WS) in
2009. Prior to sowing, seeds were incubated in the oven set at 37 °C for 12 h to break inherent seed
dormancy. Seeds were sown in a raised seedbed in the greenhouse and covered with coconut coir dust.
Seven-day-old seedlings were transplanted into the field following a planting distance of 25 cm × 25 cm.
A total of 20 plants per accession in three replicates were planted in the field for characterization.
Agronomic characters were measured and scored following the Rice Descriptors [39]. A total of
18 quantitative and 39 qualitative characters were selected to score the germplasm collections.
Figure 4. Philippine map showing the provinces (areas in green) where the rice germplasm
were collected. The map was generated using DIVA-GIS ver.7.5.0 [40].