Abstract:
Development of drought tolerant potato varieties for moisture stress areas is one of the
strategic orientation and research priorities of the Ethiopian Potato Research Program.
Estimation of variability is the first step in the process of variety development. This
research was conducted at Simada research site of Adet Agricultural Research Center, a
satellite site for drought experiments, in 2016 main rain season to estimate genetic
variability, correlation among traits and to determine genetic diversity among 105 potato
genotypes that included five checks. The experiment was laid out in Augmented design and
data were collected for 20 traits. The analysis of variance revealed the presence of highly
significant (P<0.01) differences among genotypes for all traits considered except plant
height and small and medium size tubers percentage. Marketable and total tuber yield
ranged from 10.81 to 38.99 and 13.92 to 41.79 ton ha-1, respectively. Three new entries
(20SET4.2, 20SET4.1 and 16SET5.5) had total tuber yield advantage of 35 to 51% over the
best yielding check (Belete). Phenotypic (PCV) and genotypic (GCV) coefficient of
variation values ranged from 1.86 (SG) to 32.8 (LTP), and 1.3 (SG) to 25.5% (LTP),
respectively, while heritability and genetic advance as percent of mean estimates ranged
from 45.95(LA) to 89.15% (TNP) and 3.33 (SG) to 40.89% (UMY), respectively. Moderate
to high GCV, PCV, H2 and GAM were estimated for stem number per plant, tuber number
and yield per plant, average tuber weight, unmarketable and marketable yield, bulking
rate per plot, very small and large size tubers percentage and total starch content,
suggesting selection breeding is effective to improve these traits. Total tuber yield showed
significant and positive correlation with leaf area, tuber number per plant, tuber yield per
plant, marketable tuber yield, bulking rate, large size tubers percentage and average tuber
weight, but significant negative correlation was observed with very small tuber
percentage. Thus, selection for positively correlated traits will simultaneously increase the
total tuber yield. Genetic distances of genotypes measured by Euclidean distance ranged
from 1.11 to 12.60 and the dendrogram constructed by using the Unweighted Pair Group
Method using Arithmetic means (UPGMA) grouped genotypes into 20 major clusters. The
genotypes in different clusters are characterized by one or more desirable traits with wide
range of intra and inter clusters mean genetic distances suggesting a higher chance of
developing varieties through direct selection or crossing to produce heterotic hybrids.
