Nucleus seed

• It has 100% genetic and physical purity.
• Multiplied by selecting and growing progenies of individual pods/spikes/plants.
• Sub-divided into Nucleus seed stage I and II.
• In Nepal, nucleus seed is synonymous to breeder seed.

Breeder seed

• Breeder seed is the progeny of nucleus seed produced by the research institutes and agricultural universities under the supervision of plant breeder to provide genetically pure seeds for foundation seed production.
• Produced as a result of hybridization, selection and mutation.
• Possess all the required genetic characters.
• Are of a high genetic value in very little quantity and are very costly.
• Sub-divided into Breeders seed Stage I (progeny of nucleus seed) and stage II (progeny of stage I).
• Breeders seed stage II is allowed when seed supply is short and need to be multiplied for efficient seed supply chain.
• Golden yellow tag.

Foundation seed

• Progeny of breeders seed and second grade seed in order of its genetic purity.
• Confirms prescribed field and seed standards though there may be slight degeneration during the process of multiplication of breeder seed.
• Production done generally by the government farm or by certain organizations (NARC, Cooperatives, National seed Corporation of Nepal).
• A strict seed plot technique that includes inspection, roughing, weed control, isolation etc. is adopted during the seed production process.
• Sub-divided into FS stage I (used for production of FS stage II and Certified seeds) and FS Stage II (used only for production of Certified seeds).
• White tag and available in limited quantity.

Certified seed

• Certified seed 1st generation is the progeny of foundation seed.
• Produced in such a way that the specific genetic identity and purity is maintained according to the standards specified for the crop being certified.
• Produced in government farm or by certain registered organizations (Co-operatives and Private seed companies) under direct supervision of certifying agencies.
• During the period of seed production, the seed inspectors inspect the field and the seed thus produced is processed, bagged and tagged in the presence of seed technician of the seed certifying agency.
• Tag with blue border.

Improved seed

• Improved seed is the progeny of certified seed.
• Produced in the farmer’s field with supervision of certifying agencies.
• Have a wide range of adaptability, tolerance to adverse environmental conditions such as drought, flood and frost.
• Quality is acceptable to the local market and consumers.
• Available in sufficient quantity.
• Yellow tag and used for commercial cultivation of crops.

Hybrid seed

• Hybrid seed is the seed produced by hybridization i.e. crossing between two or more homozygous or inbred lines to obtain a desirable type having high yield potential.
• Only the F1 generation of hybrids is recommended for use as seed.
• To obtain such F1 hybrid seeds, parents are to be maintained and freshly bred each time particularly if the same vigor and known desired qualities are to be maintained.
• Hybrid seeds may be the product of single, double or multiple crosses.

Composite seed

• Composite seeds are produced by inter-crossing a number of selected varieties by making germplasm complexes.
• Such composites possess the genetic potential for high level of production and are comparatively more stable than hybrids.
• Thus, they need not be replaced after F1 generation for commercial production.

Mutant seed

• Mutant seeds are the seeds produced by mutation breeding with the help of mutagenic agents.
• Mutant seeds have higher potential in yield with superior quality and are stable compared to hybrid and composite seeds.