There was variation of grain yield among 10 upland rice varieties.
KMC had the highest grain yield (623.3 kilogram per rai)
KDK had the lowest grain yield (226.6 kilogram per rai)
Increasing of grain yield among 10 upland rice varieties was positively correlated with yield components of length of panicle, total seed and number of branch ,but it was not correlated with filled seed and unfilled seed.
Harvest index of the 10 upland rice varieties was significantly correlated to grain yield.
Increasing grain yield of upland rice varieties can be done by improving some yield components and harvest index.