Measuring physical quality of paddy

What are the properties of paddy that require measuring?

1. Moisture (see measuring moisture content of rice)
2. Cracked grains
3. Grain dimensions 
4. Immature grains
5. Dockage
6. 1000-seed weight

Measurements

Crack detection

Using the paddy crack detector, count the number of cracked grains in a 100-grain sample; then compute the % of cracked grains using the equation:

Grain Dimensions

Using the Vernier caliper or photographic enlarger, collect 20 paddy samples at random from each replicate and measure the dimensions to obtain the average length and width of the paddy grains. To obtain the paddy shape, the following equation will be used.

Paddy will be classified based on standards set by the International Organization for Standardization (ISO) for paddy.

Immature Grains

1. Select a 25-g grain sample.
2. Select, segregate, and weigh the immature grains in the sample
3. Calculate the percentage of immature grains in the sample using the formula:

Dockage

• Remove light foreign matter, stones, weed, and seeds from a 100-g sample.
• Obtain the total weight. Then compute dockage percentage as follows:

1000-seed weight

For more information:

Visit the Rice Knowledge Bank website (http://www.knowledgebank.irri.org), email postharvest@irri.org; or call +63 2 580 5600.