Methods for stimulating the growth of non-leguminous plants are disclosed. In the methods, a non-leguminous plant, a part thereof, or a seedling or seed thereof is contacted with a composition comprising a chitooligosaccharide (CO) having the formula:R1 is —H, —CH3, —COCH3, —SO3H, —SO3Na, arabinose, methylated arabinose, fucose, or methylated fucose R2 is —H, —CH3, —COCH3, —SO3H, —SO3Na, arabinose, methylated arabinose, fucose, or methylated fucose each R3 is independently —H or —COCH3 and n is 0, 1, 2, 3, 4, 5 or 6. As non-limiting examples, the method can be used to stimulate production and yield in a cereal grain crop plant, such as rice, wheat or corn (maize).
