Abstract:
An evaluation of genetic variability is useful for plant breeding and in the development of efficient
crop genotypes for different conditions. Eighty-one upland rice (Oryza sativa L.) genotypes were
tested for 15 quantitative traits in simple lattice design to assess the genetic variability and
association among traits at Mecha district, Bahir Dar University research station, under irrigation
condition in 2020/2021. Analysis of variance revealed the presence of significant differences among
genotypes for all traits. Moderate to high genotypic and phenotypic coefficients of variation was
exhibited by grain yield, biomass yield, harvest index, grain width, plant height, filled grain per
panicle and primary branch per panicle; indicates that simple selection can be practiced for further
improvement of these characters. Moderately high to very high estimates of heritability (>60%)
coupled with high genetic advance (>20%) were obtained for plant height, number of primary branch
per panicle, unfilled grain per panicle, biomass yield, harvest index, grain width and grain yield. This
indicating that selection may be effective for these traits in order to obtain maximum genetic gain for
yield improvement in rice by simple selection process. The phenotypic and genotypic correlations
revealed that grain yield had positive and significant correlations with plant height, number of
primary branch per panicle, filled grain per panicle, and biomass yield and harvest index on grain
yield. Indicated that, considering these traits improving upland rice through selection would be
effective. Path coefficient analysis revealed maximum positive direct effect of harvest index and
biological yield on grain yield. This indicates considering of these traits during selection of rice
genotypes would be more rewarding to evolve potential varieties of upland rice. The first six principal
components with Eigen values (3.09, 2.83, 2.38, 1.36 1.11 and 0.96) accounted for 78.18% of the total
variation among genotypes. Cluster analysis showed that genotypes were grouped into six clusters
with maximum inter-cluster distance between cluster IV and II (D2 =77.7) and cluster III contains the
desired genotypes that had better panicle length and grain yield. The result of this study demonstrated
that there is considerable variability among the genotypes