HOMEABOUT USCOLOPHONCONTACTPUBLICATIONSLINKS

Glossary: Farmers and seed

Accession or entry A population or line in a breeding programme or germplasm collection; also an individual sample in a germplasm bank.

Breeder's seed

Seed stock produced by the breeder or by the agency licensed to produce or maintain a variety.

Double cross hybrids

Hybrid resulting from a cross between two other (single cross) hybrids.

Formal seed system

Seed production, control and distribution activities carried out by the public and commercial sector. This may include breeding.

GxE interaction

Genotype by Environment interaction. Phenomenon that two (or more) varieties will react differently to a change of environment.

Hybrid

An individual produced from genetically different parents. The term is often reserved by plant breeders for cases where the parents differ in several important respects. Hybrid are often more vigorous than either parent, but cannot breed true.

Hybrid vigour (heterosis)

The exhibition by a hybrid of a more vigorous growth, greater yield, or increased disease resistance than either parent.

Inbred line

Genetically (nearly) homozygous population, derived through several cycles of selfing (see below), also used for hybrid seed production.

Informal seed system, local seed system or farmers' seed system

Seed production and exchange activities by farmers and grassroots organizations.

Labelling

Attaching labels to seed lots with information on variety identity, purity and seed quality.

Mass selection

Selection of individual plants from a population. Mass selection may be positive and negative selection. Seeds from mass selection form the next generation.

Modern varieties (MVs)

Varieties developed by breeders in the formal system.

Off-type plant

Plant that is morphologically different from the variety or the types that constitute a given population.

Participatory crop improvement (PCI)

includes PPB and PVS (see below).

Participatory plant breeding (PPB)

Plant breeding (crossing and subsequent selection in the heterogeneous progeny) involving farmers.

Participatory variety selection (PVS)

Selection between stable lines or populations involving farmers.

Quality-declared seed

Terminology introduced by the FAO, for a seed system in which a proposed 10 per cent of the seed produced and distributed is checked by an autonomous seed control agency and the rest by the seed producing organisation.

Qualitative trait or discontinuous variation

Variation between individuals of a population in which differences are marked and do not grade into each other, normally brought about by the effects of different alleles at a few major genes. The traits exist only in a limited number of specific forms or are absent.

Quantitative trait or continuous variation

Variation between individuals of a population in which differences are slight and grade into each other. Quantitative traits are usually those that are determined by a large number of genes and/or considerable environmental influences, e.g. weight of yield or plant height.

Seed certification

Assurance of varietal identity and purity through generation control (i.e. control of origin and class in the multiplication from breeder seed to basic seed), inspection and labelling.

Seed quality control

Control of physiological, sanitary and genetic seed quality characteristics.

Seed regulation

The total set of rules and protocols related to variety development and release, seed production, quality control and delivery.

Selfing

The process whereby members of a particular generation resulting from a specific cross are allowed to breed among themselves, but not with individuals from other crosses.

Silking

Female flowering in maize, i.e. moment that silks emerge from the husk.

Single cross hybrid

Hybrid resulting from a cross between two inbred lines.

Source community

Community from which a local variety or a seed lot originated.

Stratified mass selection

Mass selection in which the population is split into subpopulations that are grown under different environmental conditions (i.e. in different fields or in different parts of a field). Plants for next generation seed are selected from the different subpopulations.

Sui generis

‘of its own kind’, an intellectual property right system on plant varieties.

Three-way cross

This hybrid is produced over two generations. A single cross hybrid is produced in the first season and crossed with an inbred line in the following. This additional production step requires resources in terms of time, land and money, but it normally guarantees for more reliable yields than inbred lines.

Truthfully labelled seed

Seed with label of the producer with information on the seed quality.

Conny Almekinders