Laboratory analysis of seeds of agricultural crops is an important stage for determining its quality and suitability for sowing. It includes the study of various indicators, characterizing varietal and sowing qualities of seeds.
Main indicators of seed quality, which are determined during laboratory analysis:
- Seed purity: The percentage content of seeds of the main crop in the total mass of seeds is determined. The content of garbage and seed impurities is also determined.
- Seed moisture: The moisture content in the seeds is determined in percent. Optimum humidity is important for seed storage and germination.
- Masa 1000 seeds: The average mass of a thousand seeds in grams is determined. This indicator is used to calculate the sowing rate.
- The energy of germination: The percentage of seeds is determined, which germinated in the first few days (usually 3-5) in optimal conditions. This indicator characterizes the viability and speed of seed germination.
- Similarity of seeds: The percentage of seeds is determined, capable of forming normal sprouts within the prescribed period (usually 7-10 days) in optimal conditions. This is the main indicator, which characterizes the suitability of seeds for sowing.
- Seed viability: The ability of seeds to remain alive is determined, even if it did not germinate under standard conditions. This indicator is important for assessing the potential germination of dormant seeds.
- Infection with diseases and pests: A visual inspection and laboratory tests are carried out to detect pathogens and pests on the surface and inside the seeds.
- Varietal purity: The conformity of the seed to the declared variety is determined by morphological characteristics. Modern laboratories can also use DNA tests to confirm varietal purity.
- GMO content: If necessary, an analysis is carried out for the presence of genetically modified organisms.
- The content of oil and other substances: For oil crops (sunflower, rapeseed, soybeans) the oil content is determined. Protein content can be determined for other crops, starch and other important substances.
Methods of laboratory analysis:
Different methods are used to determine these indicators, provided by the relevant state standards (DSTU) and international standards (ISO). The main methods include:
- Visual inspection: Color evaluation, smell, the presence of mechanical damage, impurity.
- Division into factions: Manual or mechanical separation of seeds into the main crop, impurities, broken and damaged seeds.
- Determination of humidity: Method of drying in a drying cabinet to a constant mass.
- Germination: Decomposition of seeds on a moist substrate (filter paper, sand, if) under controlled conditions of temperature and humidity.
- Tattooing (dyeing method): Determination of seed viability using special dyes.
- Phytopathological analysis: Microscopic examination of seeds to detect pathogens.
- Entomological analysis: Visual detection of pests.
- Chemical methods: Determination of protein content, fat, starch and other substances.
- Molecular genetic methods (PCR): Determination of varietal purity and presence of GMOs.
The results of laboratory analysis of seeds are the basis for making decisions about its use for sowing, storage or sale.