seed sampling.xlsx Flashcards
Purpose of Sampling
Sampling is done to get a uniform and representative sample from a seed lot.
Importance of Sample Size
The size of the submitted sample is small compared to the seed lot, so it must represent the lot accurately.
Sample Preparation
Samples must be prepared following established procedures like ISTA rules to ensure they represent the seed lot accurately.
Seed Lot Definition
A seed lot is a specified quantity of seed of one cultivar, of known origin, that is physically identifiable.
Seed Lot Accession Number
Seed lots received by the laboratory are given an accession number for each variety for future reference.
Homogeneity of Seed Lot
A seed lot must not be heterogeneous; primary samples from the lot should have similar constitution.
Sampling Definition
A sample is obtained by taking small portions at random from different parts of the seed lot and combining them.
Seed Lot Definition (Test)
A seed lot is a specified quantity of seed for which a seed test certificate can be issued.
Primary Sample
Each probe or handful of sample taken from a bag or bulk is called a primary sample.
Composite Sample
All the primary samples drawn are combined in a container to form a composite sample.
Submitted Sample
The composite sample reduced to the required size for submission to the seed testing lab, obtained by repeated halving and random portion combination.
Working Sample
A working sample is the reduced sample obtained from the submitted sample, on which seed quality tests are conducted.
General Sampling Procedures
Equal portions are taken from evenly distributed parts of the seed lot; use probes for free-flowing seeds and hands for non-free-flowing seeds.
Representative Sampling
Follow different paths when drawing multiple samples; sample all bags for lots of 1-6 bags, or sample 5 bags + 10% for larger lots.
Hand Sampling
Used for non-free-flowing seeds (cotton, grass), but difficult to access deeper layers; bags are emptied for deeper sampling.
