Effects of paclobutrazol (PP333) on seed quality for western wheatgrass

Low seed quality of western wheatgrass in China was caused by lodging and harvesting dates. The trials were conducted with 3-year western wheatgrass to study the change of seed quality after PP333 spraying in Jiuquan area of Gansu Province. The results showed thatspraying PP333 in three-leaf stage reduced western wheatgrass seed moisture decreasing rate during late seed development period. Seed moisture decreasing from 45% to 35% needs 3 d in CK but 6～9 d after spraying PP333, which made the seed maturation tend to be consistent and reduced grain losses effectively. When the PP333 spraying rate was 2.40 kg·ha-1,the most suitable harvest date western wheatgrass was the 42nd day after full-bloom stage because the seed dry-weight and standard germination percentage was the maximum value at that time.