Abstract

Seed size was physical grain quality with important. Breeding for Thai rice standard must be long grain and slender shape. Thus, the objective of this experiment was to evaluate grain size and grain shape of F₈ lines obtained from crosses Prayaleumgang x Chanat1 and Prayaleumgang x Suphanburi 3, 16 and 9 lines respectively. The results indicated that 10 lines of PLG X CNT1 and 8 lines of PLG X SPR3 were classified into long grain to very long grain. While, grain shape was evaluated that 11 lines of PLG X CNT1 and 8 lines of PLG X SPR3 were classified into slender. Grain size and grain shape were combined considering. The results indicated that there were 8 lines of both crosses were long grain and slender. The information of this experiment will be using lines selection.