In all measurement occasions (DS1–DS3) of drought score, drought score was small and after 42 days of drought period at DS3, it reached a mean value of only 3.3 (Table 3). Thus, the drought environment was classified as slow development of mild drought. Drought score was not significantly different among populations (P>0.05), but genotypic variation occurred within each population ( Table 3). There was a significant relationship between DS1 and DS2 (r=0.623**) and between DS1 and DS3 (r=0.343**), and also between DS2 and DS3 (r=0.749**).