Selection of Early Maturity and Semi-Dwarf Stem Mutants in The M2 Population of Local Rice of the Singgam Putih Genotype from Kuantan Singingi District, Riau

Selection is an important stage in mutation breeding. The selection stage determines the candidates to be obtained in the target mutant, especially early maturing mutants and mutants with semidwarf stem features. The aim of this study was to select early maturing mutants and semidwarf stem features in the M2 population of the local rice genotype Singgam Putih from Kuantan Singingi Regency, Riau Province. The study was conducted in rainfed rice fields in Pebaun Hulu Village, Kuantan Mudik District, Kuantan Singingi Regency, Riau Province. The material in this study was seeds resulting from the irradiation of M1 generation seeds in the M2 population. The parameters observed included chlorophyll mutations at the seedling stage, plant height (cm), number of productive tillers (stems), plant age (days), and panicle length (cm) at the planting stage in the field. The results showed that it could cause significant phenotypic diversity in the M2 population both at the seedling stage and the planting phase. During the nursery phase, chlorophyll mutations were found in the leaves of rice seedlings, namely: the Tigrina mutation, the Albina mutation, the Marginata mutation, and the Striata mutation. Field planting results showed a 20–30% reduction in plant height compared to the control and an acceleration of flowering age up to 10–15 days earlier. The frequency of semidwarf mutants was 0.7%, while early maturing mutants were 0.5%. Several mutant individuals showed a combination of both traits with yield potential equivalent to or even higher than that of the control plants. These findings indicate that a dose of 300 Gy is effective in inducing beneficial genetic variation in the White Singgam genotype, which can be used as a basis for the formation of superior early maturing and semi-dwarf mutant lines for the development of adaptive and high-yielding local rice varieties.