Response growth and yield to plant density and row space under rainfed conditions in wheat

In order to evaluation of plant densities and row spacing effects on growth and yield of wheat, an experiment was conducted by using four plant densities (125, 250, 375 and 500 plants per m2), two row spacing (12.5 and 25 cm), in a randomized complete block design with three replicates in Anbare-Ololum reign in rainfed and saline conditions during 2008-2009. Results showed that leaf area index (LAI) corresponded to stem elongation stage was higher in row spacing of 12.5 (in comparison with row space of 25 cm), but in spite of stem elongation stage, this was inverse in booting stage. Increasing of row space decreased stem number, but increased plant height, while did not affect fertile stems number. Morover, dry matter and yield corresponded to row space of 25 cm was higher than 12.5 cm (about 11%). In addition, grain yield of 250 and 375 plants per square meter treatments increased 30&48% in comparison with 125 plants per square meter, respectively. But increasing of plant density upper than 375 to 500 plants per square meter did not affect grain yield significantly. Interaction of plant density and row spacing treatments revealed that dry matter, 1000-grain weight and harvest index with using row space of 25 cm was more than row space of 12.5 cm in all plant densities, Overall, it seems that row space of 25 cm decreases stem number per unit area without reducing fertile stems number, while it increases dry matter, plant height, grain yield and harvest index.