| Abstract: The growth characteristics of two spinach cultivars at different sowing dates before winter were compared and analyzed, which provided the best sowing date and scientific basis for high yield and high quality cultivation of overwintering spinach in northern Xinjiang. Two spinach cultivars, 'Green crown 369' and 'American big leaf', were sowed on August 15, August 25 and September 15, 2018, respectively, and the related morphological indexes were determined on October 16. The results showed that two different spinach cultivars could grow normally at three sowing dates. The number of leaves per plant and fresh weight per plant of 'American big leaf' decreased gradually with the delay of sowing date, and there were significant differences among sowing dates, but there was no significant difference in plant height and relative chlorophyll content between August 15 and August 25. The number of leaves per plant of 'Green crown 369' spinach decreased gradually with the delay of sowing date, but there was no significant difference in the height per plant, fresh weight per plant and relative chlorophyll content between the first two sowing dates. The number of leaves per plant of 'American big leaf' spinach sown on September 15 was 5, and that of 'Green crown 369' spinach was 6.67, all of which met the requirements of safe overwintering of spinach. The spinach cultivars sown at about 20~25 ℃ in autumn in northern Xinjiang could be supplied to the market or false planting for storage before winter. The growth indexes of the two spinach cultivars sown at an average temperature of about 15 ℃ before winter were the most suitable for overwintering. |