Evaluation of rice varieties for adaptability and genetic variability under rainfed conditions in Ebinat district, northwestern Ethiopia

<h2>Abstract</h2> Rice is an important strategic food security crop in Ethiopia, ranking second in productivity after maize. The northwestern region of Ethiopia is the primary rice-producing area, yet rice cultivation remains limited compared to its potential. To address this gap, a study was conducted during the 2020–2021 main cropping seasons to evaluate the adaptability and genetic variability of rice varieties for potential expansion into new areas. Eleven rice varieties were assessed for yield and agronomic performance using a randomized complete block design (RCBD) with three replications at two locations, Zeha and Mechena, in the Ebinat district, South Gondar, Ethiopia. The objective was to identify high-performing varieties suited for expansion. Combined analysis of variance across years and locations revealed significant (P ≤ 0.05) differences among varieties for yield and other agronomic traits. While most varieties exhibited inconsistent performance across years, the variety <i>Shaga</i> demonstrated stable performance with a relatively higher yield. <i>Shaga</i> recorded the highest grain yield, showing a 41.6 % yield advantage over the lowest-yielding variety, <i>Chewaka</i>. Genetic variability analysis indicated the presence of substantial variability among the tested varieties. The phenotypic coefficient of variation (PCV) was higher than the genotypic coefficient of variation (GCV) for all measured traits. High PCV and GCV values (>20 %) were observed for grain yield and the number of effective tillers per plant. Additionally, broad-sense heritability and genetic advance as a percentage of the mean (GAM) were highest for grain yield, total tiller number, and effective tiller number per plant. Given the high heritability and genetic advance of yield-related traits, coupled with the consistent agronomic performance of <i>Shaga</i>, this variety is recommended for cultivation in the test locations.