Early maturity upland crop cultivars allow sequential and relay cropping in either pre- or post-rice cropping patterns. The cultivars have shorter competition periods with rice when intercropped. When a short duration cultivar is not available, maturity of existing cultivars can be altered through the crop's sensitivity to pbotoperiods and temperatures: This alteration is achieved by careful planting date manipulation.   Some cultural practices can also reduce crop harvesting time. Two different species with similar maturity and crop phenology can have different adverse effects on the main crop. Thus, earliness should not be emphasized as .a criterion for choosing field crop species. However, it is more meaningful to compare the maturities of cultivars from a given species.

Early maturity upland crop cultivars allow sequential and relay cropping in either pre- or post-rice cropping patterns. The cultivars have shorter competition periods with rice when intercropped. When a short duration cultivar is not available, maturity of existing cultivars can be altered through the crop's sensitivity to pbotoperiods and temperatures: This alteration is achieved by careful planting date manipulation.   Some cultural practices can also reduce crop harvesting time. Two different species with similar maturity and crop phenology can have different adverse effects on the main crop. Thus, earliness should not be emphasized as .a criterion for choosing field crop species. However, it is more meaningful to compare the maturities of cultivars from a given species.