Glossary Plant Breeding

provide conditions to facilitate flowering of photosensitive and late maturing
genotypes and thus provides rapid generation advancement. Conducive conditions for
screening of genotypes against biotic and abiotic stresses can also be created.
Pima Cotton. Gossypium barbadense; also called Egyptian cotton.
Pinocytosis. The process of active intake of sizable droplets of fluids by the cell.
Plant Breeders’ Right. A system of intellectual property right (IPR) that provide patent
type protection to traditionally bred varieties. It is specifically designed to cope with
the inherent variability of plant materials. It gives to the holder the rights and ability
to recoup his development costs from the market over a period of years.
Plaque. A clear area on a bacterial lawn, left by lysis of the bacteria through progressive
infections by a phage and its descendants.
Plasma Membrane. A unit membrane surrounding the outer layer of the cell’s
cytoplasm. It is selectively permeable.
Plasmid. Autonomously replicating extrachromosomal DNA molecule found in bacteria.
It is not the essential component of bacterial genetic material. Its presence is
correlated with stress condition and confers resistance to certain antibiotics. These
properties of plasmid make it suitable for exploitation as a vehicle in genetic
engineering.
Plasmodesma. Any of the fibrillar plasma connections extending through the cell wall
and forming the bridge between adjacent cells.
Plasmogamy. The fusion of the cytoplasm of two or more cells. It precedes karyogamy in
the process of fertilization.
Plasmotype. The sum total of extrachromosomal hereditary determinants. Plasmotype
and genotype together constitute the idiotype or genetic system of the cell.
Plant Introduction. Bringing of a plant species or a variety from one place/environment
to a new place/environment where it has not been grown previously. When
successful, plant introduction serves the same purpose as developing varieties in a
well-developed breeding programme. In the past, it has played important roles in the
movement of plant species/varieties from one place to the other, for instance, the
introduction of soyabeans in India from China. These introductions are utilised
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