Effect of devernilization and planting time on growth and yield on onion

Abstract

This study was conducted in al soofia area of AL-Ramadi city a 90 Km west of Baghdad for the agricultural season 2014-2015 to study the effect of planting time and period exposure of devernilization on the growth and production of onion Texas Early Grano. The study includes two factors. The planting time which include four times: 1/Nov, 15/Nov, 1/Dec, 15/Dec and the exposure to devernilization period 20 c0. This factor includes the exposure of seedling to three periods 24, 48, and 72 hours,and the comparison with the other that are not treated by devernilization, the results showed, that the fourth date 12/15 leads to increase the number of tubular leaf, leaf area and blubbing percent plant product and the total product for unit area which is 12.33 leaf/plant, 50.88 dcm2/plant, 95.30%, 243.47 gm/plant, 42.23 ton/h, The fourth date also leads to decrease flowering 4.73 %. The treatment with devernilization 72 h, lead to increase the number of tubular leaf and leaf area and blubbing percent plant product and the total product for unit area which is 13.10 leaf/plant, 45.97 dcm2/plant 72.42%, 196.93 gm/plant 34.16 ton/h, and decreasing flowering percent 27.44 %.The interaction result between study factors showed the exceeding of fourth date treated plant 12/15 and the exposure of 72 h from devernilization and orient in the some of previous factor orientation.