Genetic and Cytogenetic Characterization of Local Rice (Oryza sativa L.) Varieties from Chalan Beel

An experiment was conducted in the Agronomy Field Laboratory, along with a laboratory experiment at the Farming System Engineering Laboratory, Department of Agronomy and Agricultural Extension, University of Rajshahi, from mid-May to mid-November 2024. Eight rice genotypes were analyzed to understand their genetic variation, heritability (broad sense), genetic advance, and karyotype details. The study design followed Randomized Complete Block Design (RCBD), and each treatment was repeated three times, evaluating agronomic traits like plant height, leaf number, tiller number, effective tillers per meter², panicle length, grains per plant, filled grains, 1000-grain weight, straw yield, yield of grain, and biological yield. Significant variation was observed across most traits. Grain yield exhibited the highest genotypic (GCV) and phenotypic coefficient of variation (PCV), followed by plant height, while grain per plant and 1000-grain weight showed the lowest. For each trait, the phenotypic coefficient of variation (PCV) was slightly higher than the genotypic coefficient of variation (GCV), indicating a measurable environmental influence on trait expression. Heritability was observed to be high in the case of 1000-grain weight, followed by panicle length and grain yield, whereas the height of the plant showed the highest genetic advance. For karyotype analysis, metaphase plate photomicrographs, camera-lucida drawings, and idiograms were used to assess total chromosome length (TCL), arm ratio, centromeric position, TF%, and karyotype formulae. The highest TCL with the lowest TF% was observed in SADA VAULA, while the lowest TCL with the highest TF% was recorded in BINA-7. The combination of high heritability and genetic advance for traits like plant height and grain yield indicates the predominance of additive gene action and suggests good potential for improvement through direct selection.