HETEROSIS AND HETEROTIC GROUPING EFFECTS ON GRAIN YIELD, HEIGHT, TILLER DENSITY, AND DAYS TO HEADING IN HYBRID RICE (ORYZA

Heterotic groups are necessary for high vigor in hybrid rice. However, hybrids produced from crosses between parents different rice subspecies (i.e., Indica × Japonica) have extensive incompatibility issues exhibited by low seed sets. The study objectives were to evaluate the heterosis grain yield and yield-related traits parental genetic distances (PGDs) demonstrate heterotic group approach From PGDs, eight three assigned PGD groups, respectively. Neighbor-joining clustering model-based population structure analyses classified into four with found consisting of intra-subpopulation intersubpopulation crosses, Replicated trials conducted at Beaumont, Texas, transpired 2019 2020. normal sets, least one each hybrid's determined possess wide compatibility S5n allele sets crosses. Trait standard values estimates included number days heading, plant height, tiller density, yield. Higher trait density occurred than group, especially inter-subpopulation indica had consistent positive correlations (r = 0.41 0.60) (0.28 0.36) both years. PGDs aid determining highly cross combinations forming groups. grouping is advisable through cluster genome-wide markers instead identifying genetically-distant based on pedigree information.