Abstract

The softness of cooked rice is an important eating quality trait that strongly influences consumer preference and the market value of rice. This study aimed to evaluate and select F₅ rice lines derived from the cross between PTT1 and RD41 based on the softness of cooked rice grains, using the grain spreading method as the evaluation criterion. The results revealed significant variation in physical softness among the F₅ lines, with values ranging from 0.63 to 1.03. Lines 3-54-2 and 3-21-1 exhibited high spreading values comparable to the female parent PTT1, which is characterized as a soft-textured rice variety. In contrast, line 3-134-2 showed the lowest spreading value, similar to the male parent RD41, which is classified as a hard-textured rice variety. These findings demonstrate clear differences in cooked rice softness among the F₅ lines and indicate that both soft- and hard-textured rice lines can be effectively selected at this generation. The results provide valuable information to support the selection of superior rice lines for further breeding and variety development.