2.2 Molecular Screening
Molecular studies were conducted at the State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China, using the 20 mg silica gel-dried leaves collected from six Oryza types from Sri Lanka. Preliminary screening of 150 pairs of simple sequence repeat (SSR) loci across representative individuals sampled from different populations revealed that 33 SSRs produced clear and reproducible products. These 33 SSR primer pairs were designed based on cultivated rice sequences from the RiceGenes Database (https://gramene.org), and used to assess the genetic variation of DWWC in this study. The 33 loci were dispersed in all 12 chromosomes in the rice genome, with the polymorphism varying widely among loci. Detailed information on the primer pairs is given in Table S4. Primers were synthesized by ABI DNA Analyzer (Applied Biosystems, Foster City, CA, USA), with the forward primers labelled with blue (FAM), yellow (TAMAR), and green (HEX) fluorophores.