The main target of the current study was to develop a new local cultivar of spinach with delayed bolting which characterized by late-flowering based on the multitrait selection for quality traits through the disposal of the male plants in the spinach population and increasing the percentage of females and no bias plants. This study was carried out at Kaha Vegetable Research Farm (Kaluobia Governorate, Egypt). Means, genetic and phenotypic parameters of population performances had been recorded for the characteristics of plant growth, yield and its components as well as chemical compounds. One genotype, Dokki cv. (a local cultivar as original population) was used. The selection program began on the first of September 2014 and continued to the year 2017 (four years), where a comparison experiment was conducted between the original and the selected population during 2018 and 2019-under high temperature in an early season-to measure the progress in achieving the goals of the selection program. The selection program based on multitrait selection under high temperatures in the early season had clear effects on genetic and phenotypic parameters. Moreover, the multitrait selection based on selection indices showed differences consistent with the goal of the selection program in all vegetative characteristics, delay bolting and chemical content of leaves that were significantly improved in the selected population compared to the original population.