2.1 Plant materials
A total of six WR populations occurring in the early (code as WRE) and
late (WRL) rice-cultivation seasons were collected from three rice
fields in Leizhou, Guangdong Province of China (Table S1). The
geographic distance between the sampled rice fields were
>30 km. WR populations collected from the same field were
treated as a population pair (e.g., CDE/L, DCE/L or HJE/L pair). About
60 randomly selected samples were collected from each WR population of
either the early- or late-season rice field at the spatial distance
intervals of >10 m to avoid the sampling of similar
genotypes. Matured panicles from a WR plant were collected as an
independent sample. The average duration of the early rice-cultivation
seasons (ES) was from March 1st to June
25th, whereas that of late rice-cultivation seasons
(LS) was from July 20th to November
5th.