In this study, eleven diverse germplasm lines and their 55 F1s were morphologically evaluated for 10 economically important quantitative traits in garden pea. These germplasms were also screened to identify resistant sources against the powdery mildew disease. Among 11 parental lines evaluated, GP-17 was superior for earliness while pod length and width were highest in VP-233. Maximum number of seeds per plant, pod weight and shelling percentage were recorded in genotype GP-473. The maximum number of pods per plant were observed in IP-3 whereas, the highest yield per plant was recorded in VRP-7. Among F1 crosses, Arka Ajit × Pusa Pragati was the earliest and GP-17 × VRP-7 was superior for number of pods per plant. The maximum pod length, pod width, pod weight and number of seeds per pod were observed in GP-17 × VP-233, VRP-7 × IP-3, Arka Ajit × GP-6 and Arkel × VRP-7, respectively. Maximum shelling percentage was recorded in VP-233 × AP-3 while VP-233 × IP-3 gave maximum yield. Based on screening data, five genotypes (GP-6, GP-473, Arka Ajit, Pusa Pragati and VP-233) exhibited percent disease index (PDI) in the range of 2.54 to 7.78 and were considered resistant to powdery mildew and can be utilized as resistant sources in breeding programmes. The mendelian segregation ratio in six generations (P1, P2, F1, F2, BC1 and BC2) of five cross combinations using chi-square analysis showed that a monogenic recessive gene controls powdery mildew resistance in garden pea and it can be introgressed by backcross breeding in the popular and high yielding susceptible cultivars which will create a new pathway of resistance breeding in this crop.