STANDARDIZATION OF SIEVE SIZE FOR GRADING WHEAT (TRIRICUM AESTIVUM)

Wheat varieties viz. WH-711, PBW-502, HD-2967 and WH-283 were graded during the year 2012 using various sieves on seed cleaner-cum-grader in order to find out the optimum sieve size for maximum seed recovery and quality seed. The seed retained over each sieve were collected separately and tested for seed quality parameters in the seed testing laboratory. The results revealed that 2.2 mm sieve size was found effective and economical for grading WH-711, PBW-502 and HD-2967 for maximum seed recovery (94.1, 91.3 and 92.7%, respectively) with better seed quality i.e. germination (92, 94 and 92%, respectively) and physical purity (98.8, 98.8 and 98.3%, respectively) which meets IMSCS while the sieve of 2.40 mm size was found effective and economic for grading WH-283 for maximum seed recovery (92.7%) with better seed quality i.e. germination (95%) and physical purity (99.7%). The results also revealed that the recovery (%) increased with decrease in sieve size while the seed quality parameters increased with increase in sieve size.