218 Glossary
Fungicide: A chemical used to kill fungus.
Generation: One complete life cycle. The generation begins with the formation of
the zygote and end when the resulting plant dies.
Genes: Basic units of hereditary material that dictate the characteristics of individuals.
Genetic sterility: A type of male sterility conditioned by nuclear genes. In contrast to
cytoplasmic sterility, it may be transmitted by either the male or female parent.
Genotype: The true genetic makeup of a plant.
Genus: A group of species possessing fundamental traits in common but differing
in other lesser characteristics.
Germination: The initiation of active growth by the embryo, resulting in the
rupture of seed coverings and emergence of a new seedling plant capable of
independent existence.
Gibberellin: A group of compounds that naturally controls stem elongation.
Grafting: The process of joining a stem or bud of one plant on to the root stock of
a different plant so that by tissue regeneration they form a union and grow
as one plant.
Green manures: Green manuring are plant cover crops that are tilled into the soil.
Growing media: A material used to culture plants.
Growing season: The number of days between the average date of the last killing
frost in spring and the first killing frost in fall.
Grow-out test: Test performed to determine the genuineness of seed as to species
or va r iet y.
Growth regulator: A chemical used to increase growth or shorter stems.
Gynodioecy: Plant species in which individuals are either female (pistillate flowers)
or hermaphrodite (bisexual flowers). It is often regarded as an evolution-
arily intermediate stage between bisexuality and dioecy.
Gynomonoecious: Refers to a plant species in which female and bisexual flowers are
produced on the same plant.
Habit: Growth form or overall plant shape.
Habitat: Type of region in which a plant is native.
Hardening off: The process of gradually acclimatising tender plants, greenhouse
or indoor grown plants to outdoor growing conditions or survive a more
adverse environment.
Hardiness/hardy: The ability of a plant to withstand low temperatures or frost,
without artificial protection.
Hardpan: A layer in the soil that cannot be penetrated and which restricts root
penetration as well as movement of air and water.
Heading back: Cutting an older branch or stem back to a stub or twig.
Healing: The process of closing of a plant wound or graft union.
Hectare: Standard area measurement in the metric system and it equals to
10,000 square meters in area.
Herbicide: A material or chemical kills essentially all plants or be quite selective in
their activity.
Hermaphrodite: Papaya plants bear perfect flowers and correctly termed as andro-
monoecy, which indicates the occurrence of staminate and hermaphroditic
flowers on the same plant.