VARIABILITY AND HERITABILITY ESTIMATE OF 30 RICE LANDRACES OF LAMJUNG AND TANAHUN DISTRICTS, NEPAL

The variability in the rice landraces is the source of variation and offers substantial opportunity for the development of new varieties through the selection. Exploring diversity and variability of landraces is utmost for rice improvement. The objective of the study was to assess diversity indices, magnitude of genetic variability, heritability, genetic advance for the yield, and yield contributing traits. An experiment was carried out in alpha-lattice with 30 landraces, two replications in the Agronomy farm of IAAS, Lamjung Campus, during June-November, 2018. Shannon and Simpson's indices were calculated for 18 qualitative traits. The value of the Shannon and Simpson index ranged 0.15-1.41 and 0.07- 0.75, respectively. Landraces showed significant variations (p<0.001) for all 13 qualitative traits studied. The higher value of the phenotypic coefficient of variation (PCV) compared to the corresponding genotypic coefficient of variation (GCV) for all the studied traits indicated the influence of the environment. The filled-grain per panicle exhibited a high estimate of PCV and GCV, followed by the effective tiller and filled grain percentage. High heritability, along with high genetic advance was found in 10 traits, including 1000 grain weight, grain length, and filled grain per panicle indicated the presence of additive gene action. Direct selection of characters of these traits based on phenotypic expression by a selection method will be more reliable for yield improvement. The study suggests that the existence of diversity and estimated genetic parameters among landraces of rice that can be exploited in future rice breeding programs.