Glossary Plant Breeding

FIS. International Seed Trade Federation. It was formed in 1924 with well defined
objectives such as: (a) to formulate and deliberate opinion of all concerned in the seed
trade, (b) to carry out continued action for the improvement of seed trade conditions
between various countries, and to find solutions to problem that affects international
seed trade, and (c) to facilitate settlement of international disputes in seed trade. In
fact, FIS is the prime international organization of the seedsmen of the world. India is
also a full member of FIS since 1968.
Fisher’s Theorem. A theorem pertaining to natural selection. “The greater the genetic
variability upon which selection for fitness may act, the greater will be the expected
improvement in fitness”. In mathematical terms, increase in fitness of a population
should be proportional to the genetic variability or genetic differences in fitness
present in the population.
FISH. Fluorescence In Situ Hybridisation. It is in situ hybridisation using a probe
coupled to a fluorescent molecule. This is a technique to characterize ‘alien’ genes
(introduced) in our crop plants. It can also be used in the study of nuclear architecture
and chromatin packaging, and the fundamental principles of biology such as DNA
replication, RNA processing, gene amplification, gene integration and chromatin
elimination.
First Division. The first of the two meiotic divisions. Also called reductional division.
Fitness. The relative probability of survival and rate of reproduction of a phenotype or
genotype. It is therefore the ability of alleles, multigenic combinations of alleles,
individuals, or populations to survive and transmit their genotype to following
generations. A population is said to have maximum fitness if its members have
optimum phenotypes for most ‘fitness’ traits. Although we loosely speak of fitness of
an individual, the concept really applies to classes of individuals, and is statement
about the average survival and reproduction of the individuals in that class. It is
distinct from physical fitness, which may be related to the survival. But a better
surviving individual cannot be called fit, if it is sterile. Fitness is a consequence of the
relation between the phenotype of the organism and the environment in which it lives,
so the same genotype will have different fitnesses in different environments. No
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