Seed Production of Vegetable, Tuber and Spice Crops (2+1)

B. Grading

• The threshed produces are precleaned either manually or mechanically and are graded using different but optimum sieve of specified sizes. This grading brings homogeneity in the lot which aids in obtaining uniformity among the population in the subsequent sowing.
Sieve size recommened for different crops

Crop	Sieve size (Perforated round metal sieve)
Tomato	- 5/64
Chillies	-5/64
Brinjal	- 5/64
Bhendi	- 10/64
Gourds	-16/64
Onion	- 5/64

In some crops weight grading is used for upgrading

Crop	Weight grading technique
Bhendi	Water floatation technique
Marigold	Floatation technique with acetone