Effects of sowing date and plant density on ear yield of sweet corn Sc.403

In order to study the effect of sowing date and plant density on quantity and quality of sweet corn SC.403, field experiments were conducted in Gorgan Reaserch Station during 2001-2003 growing seasons. In these experiments four sowing dates (April 9, April 29, May 19 and June 8) and four plant densities (45000, 55000, 65000 and 75000 plants per hectar) were evaluated in a factorial experiment (4 ×4) Using Randomized Compelet Block Design with four replications. Results showed that ear yield, ear lenght, can seed percent and ear harvest index was influenced by planting date. Maximum ear weight achieved in April 29 (20250 kg/ha). The ear yield was identical in this planting date with April 9, With dealy in planting dek anthesis period decreased and therefore ear yield reduced due to the reduction of growth period and high air temperature. Plant density effected the ear yield, ear length and harvest index. Although maximum ear yield was 18170 kg/ha in 75000 plants per hectar, but it decreased, with increase in plant density, Ear marketing, obviously decreased, not only for fresh consumption bat also for industry. Despite of significant increase in ear weight in 75000 plant per hectar it is recommended that for better marketing of sweet corn it should be planted with 55000-65000 plant per hectar in spring.