كارايي مصرف نور در هيبريدهاي ذرت با گروه هاي مختلف رسيدگي در پاسخ به تراكم

Radiation use efficiency of maize (Zea may L.) hybrids with different growth types in response to density

In order to investigate the response of yield and yield component of three maize hybrids on seven plant densities, an experiment was conducted during 2006 growing season in Mashhad, Iran. Three maize hybrids including late maturity maize (704), medium maturity maize (504) and early maturity maize (260) and seven plant densities including D1 = 3, D2= 5, D3 = 7, D4 = 9, D5 = 11, D6 = 13 and D7 = 15 plants m-2 were compared in a strip plots design with three replications. The result of this study showed the radiation use efficiency increased in proportion to an increase in the plant density: die late maturity variety of 15 plants m-2 (1.103 g MJ-1), the medium maturity of 15 plants m"2 (1.214 g M-1) and early maturity of 15 plants m"2. Density factor had significant effect on the number of row of seed per each ear, the number of seed per each ear, 100 seed weight and seed weight per plant. There was significant difference among ear diameter, ear length, number of seed row on each ear, number of seed per each ear, seed weight per each plant, 100 seed weights and weight of dry cob per each ear. The highest grain yield were obtained in third plant density (D3) for late maturity hybrid (11334 kg ha-1), in fourth plant density (D4) for medium maturity hybrid (10937 kg ha-1) and in sixth plant density (D6) for early maturity hybrid (7591 kg ha-1). When the plant density was increased more than optimum rang of density, biology yield increased and seed yield decreased. The results demonstrated that optimum yield was depended on radiation use efficiency, plant growth types and density. Our results showed that late maturity maize compared to early maturity hybrids need less density.