عنوان مقاله [English]
Seed processing is one of the most important step in wheat production cycle and more than 12 percent of wheat seed lose annually in harvesting, transportation and processing factories. More than half of seed losses occurred in the factories that can be reduced by consider some technical comments. In this paper, operational process and critical point of wheat seed process analyzed in Thehran, Alborz and Ghazvin provinces using the cause and effect diagram and matrix. Besides, the effective parameters on wheat seed losses were studied. Result of filed study showed that averagely 15 percent of wheat seed lost in harvesting, transportation and processing factories in Thehran, Alborz and Ghazvin provinces. Although, Physical purity and germination of final seed were 98 percent and 88 percent respectively, but the seed losses was considerable in reject fraction of some process steps. It occurred especially in second indented cylinder and gravity table (up to 90 perecent). Over feeding, unsuitable adjustment and lack of technical knowledge determined as effective parameters on wheat seed losses. Besides, some of seed processing machinery was old (about 20 years) and increased seed loss in compared whit new one. So, revision of seed pricing and standardization of seed processing can be suggested at the national level.