Abstract: 【Objective】 To investigate the resistance performance of potato hybrid progenies to common scab,the interrelationships among common scab incidence rate,disease area,and disease depth,as well as the segregation and genetic variation patterns of potato phenotypic traits.【Methods】 Resistance identification was conducted in a natural disease nursery,using 160 hybrid progenies from the cross between Kenshu No. 1 and Zhongshu No. 5（Combination 1） and 80 hybrid progenies from the cross between Kenshu No. 1 and Youjin（Combination 2） as experimental materials. Descriptive traits,numerical traits,and common scab-related indicators of potato were investigated to analyze the correlations among disease constituent factors,together with the resistance performance,discrete characteristics,and genetic performance of potato,and to calculate the coefficient of variation,mid-parent heterosis rates,transgressive heterosis rates,and relative heritability from the parental lines.【Results】 The common scab incidence rates for Combination 1 and Combination 2 were 10.71%-100% and 17.65%-100%,respectively;while the disease indices were 0.02-19.74 and 0.16-24.20,respectively. Highly significant positive correlations（P<0.01） were observed among incidence rate,disease area,and disease depth,and the resistance levels in both combinations exhibited transgressive segregation. The diversity indices of 10 descriptive traits in Combination 1 and Combination 2 were 0.23-1.71 and 0.26-1.33,respectively;the diversity indices of 6 numerical traits were 0.91-2.03 and 0.98-1.81,respectively. Among the 16 traits of Combination 1 and Combination 2,the mid-parent heterosis rates of potato were -33.39% to 29.38% and -19.04% to 43.20%,respectively,whereas the transgressive heterosis rates were 4.69% to 105.00% and -42.50% to 125.00%,respectively.【Conclusion】 Hybrid progeny populations derived from Kenshu No. 1×Zhongshu No. 5 and Kenshu No. 1×Youjin displayed transgressive segregation in common scab resistance levels,with highly significant positive correlations observed among common scab incidence rate,disease area,and disease depth. The variation of numerical traits in the hybrid progenies of the two combinations is more abundant than that of descriptive traits,and the heterosis performances of the hybrid progenies are varied.

Key words: Potato common scab, Resistance evaluation, Genetic diversity index, Coefficient of variation, Cluster analysis