Five rice varieties (Longjing 21, Chaobei 2, Suijing 13, Kenjing 3 and Kendao 12; Fig. 1) were planted in paddy fields (Table 1) in 2012, at five sites in Heilongjiang Province, China with different ATZs. Each variety was planted 100 m2, in random order, repeated for three times, 1 500 m2 was planted in each site. Field management was accordant in all the sites, row spacing and plant spacing were respectively 30 cm and 10 cm.