The excised root tissue inoculation method was used to evaluate resistance to cassava root rot caused by Phytophthora in 137 inbred progen GR891 cassava samples. Genetic diversity analysis， including the coefficient of variation and genetic diversity indices， was conducted on 93 samples exhibiting high or moderate resistance at 10 key agronomic traits. Results showed that among the 137 samples， 56 exhibited high resistance （40.88%）， 37 showed resistance （27.01%）， 33 were moderately susceptible （24.09%）， 9 were susceptible （6.57%）， and 2 were highly susceptible （1.46%）. In the 93 resistant samples， the coefficients of variation for 10 main agronomic traits ranged from 14.46% to 77.63%， with genetic diversity indices between 0.60 and 2.04， indicating abundant genetic variation in the resistant progeny of GR891. Correlation analysis revealed three pairs of traits with highly significant correlations and three pairs with significant correlations. Fresh tuber weight per plant was significantly positively correlated with stem diameter and tuber number per plant， with correlation coefficients of 0.490 and 0.680， respectively. Principal component analysis identified plant height， stem thickness， main stem height， tuber number per plant， and fresh tuber weight per plant as the primary features of phenotypic variation in cassava， with the cumulative contribution rate of the three principal components reaching 74.52%. Cluster analysis suggested three major categories： Category I， including 7 materials which have relatively poor performance at traits； Category II， characterized by superior overall traits with outstanding performance in yield traits and disease resistance， showing high potential for utilization and including 4 materials； and Category III， comprising 82 materials， with Subgroup IIIa exhibiting good traits and disease resistance as well as significant potential for high yield， including 9 materials. This study provides scientific evidence for selecting cassava germplasm resistant to Phytophthora root rot and informs genetic analysis for resistance traits.