Like other vegetables, Pisum sativum L. also faces storage and degradation problems. To enhance their resistance and make them enable to cope with the deterioration problems during storage, the current study was designed to develop two resistant lines of P. sativum in terms of phenolic contents and genotypes. The phenolic compounds generally have antioxidant properties and deterioration during storage which are usually due to oxidation caused by free radicals. Thus, if a variety has high phenolic contents these problems will be coped in a better way. The genotype of a plant is also important in this regard, and the best adopted species would survive in unfavorable conditions. First, the phenolic and flavonoid contents were determined in the crude extract using the Folin-Ciocalteu method. Then, the identification and quantification of phenolic compounds were carried out in the developed lines of selected plants PL-04 and PL-05, as well as in the parental varieties [Climax (female) and Falan (male)] via HPLC. DPPH assay was used to determine the free radical scavenging capabilities of the extracts of the developed verities. The genotypic differences were confirmed by DNA fingerprinting using advanced simple sequence repeat (SSR) markers. The HPLC analysis of PL-04 confirmed the presence of three phenolic compounds in an appreciable amount which exhibited a higher antioxidant activity against DPPH radicals, while in the parental varieties, two phenolic compounds were identified and exhibited lower antioxidant activities. PL-04 was found rich in phenolic compounds and affectively scavenge-free radicals which would therefore be resistant to oxidation and degradation caused by free radicals. Comparing the present findings with our previous one, P-04 was found to be resistant to powdery mildew; it was concluded that the most probable reason of the resistance was the high phenolic contents and thus long shelf life.