Glossary Plant Breeding

Saturation Mutagenesis. Induction and recovery of large numbers of mutations in one
area of the genome or in one function, in the hope of identifying all the genes in that
area or affecting that function.
Savannas. Tropical/sub-tropical grasslands usually interrupted with scattered patches of
shrubs/trees. These occur in areas in which warm-rainy season is interrupted by a
long, cool season dry spell. This long dry spell favours large seeded annuals as well as
plants with rhizomes, tubers, stolons, bulbs, etc.
Science. The systematic and real knowledge about a thing. The word has been derived
from a Latin word – sciencia – that means learning or knowledge in its widest sense.
The science pursued for the sake of its own existence is called basic science.
However, the science that becomes a means of producing material necessities of a
society is referred to as applied science.
Second Division. The second of the two divisions of a normal meiosis; also called
equation division.
Second Filial Generation. The progeny generation obtained by selfing or crossing of F 1
generation plants. It is designated by F 2 . Subsequent generations obtained by selfing
this F 2 generation plants are called F 3 , F 4 , …., etc.
Secondary Centres of Origin. The areas having appreciable extent of genetic diversity
of a plant species. Notice that these areas are found far removed from the primary
centres of origin of crop plants. Now the concept of centres of origin has bee revised
(see centres of origin).
Secondary Gene Pool. Genetic resources that include biological species having some
barriers of crossability with the cultivated species (primary gene pool). Chromosome
pairing at meiosis is not normal. However, special techniques (e.g., embryo rescue)
can overcome barriers of crossability and lead to normal seed set.
Secondary Species. (See digenomic species).
Second Cycle selection. A method of improving inbred lines. It consists of crossing two
inbred lines that complement each other in desirable attributes accompanied by
selection for desirable recombinations in the segregating generations. Also called
pedigree selection.
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