Glossary Plant Breeding

Tagging. TheuseofapieceofforeignDNAoratransposontolabelagenesothata
clone of that gene can be identified readily in a library.
Taichung Native-1. A variety of rice introduced from Taiwan in 1966. It heralded the
beginning of cultivation of photoinsensitive rice in India. It was developed from a
cross between Tsai-yuan-chung and Dee-geo-woo-gen.
Tandem Duplication. Adjacent identical chromosome segments (abcdbcdef). Whether
tandem or reverse tandem, duplication supplies additional genetic material capable of
evolving new functions.
Tandem Selection. Successive selection of different types one after another through one
or more cycles. For example, screen a population intensively for resistance to pest A
through one or more cycles of selection, then repeat the same for pest B, and then for
pest C.
Tautomeric Shift. The spontaneous isomerization of a nitrogen base to an alternative
hydrogen-bonding structure/ condition, possibly resulting in a mutation.
Taxon. A group of similar individuals sharing a set of characters that are considered
sufficiently distinctive to be worthy of a formal name.
T-Chromosome. A monocentric chromosome whose terminal segments (T-ends) show
neocentric activity at meiosis.
T-DNA. A part of the Ti plasmid that is inserted into the genome of the host plant cell.
Technology. The application of art and science to the welfare of mankind. In its broadest
sense, it is the applied aspect of art and science collectively. As plant breeding is
concerned with the art and science of improving the heredity of crop plants in relation
to their economic use, it is essentially a technology.
Technology Mission. A technology oriented mission that was launched by the
Government of India during 1986. Initially it included programmes pertaining to
improvement in production of oilseeds, availability of drinking water, and child
immunisation. Later on, several other programmes such as literacy,
telecommunication, dairy development, and enhancement of pulses and sugar cane
232