The researchers studied 30 types of upland rice to see how they differ in grain yield and related traits. They found that there is a lot of variation among the rice types, especially in traits like yield per plant, panicle weight, and 1000-grain weight. Traits like plant height, tillers per plant, and grain weight are highly heritable and can be improved through selection. The weight of 1000 grains is closely linked to yield, making it a good trait to focus on for breeding better rice varieties.