Rainfed rice - IRRI books - International Rice Research Institute

Traditional Varieties vs.
Modern Varieties:
Potentials and Risks
What are traditional varieties?
T
raditional varieties are those that
have been cultivated regionally by
farmers for centuries. These are
grown to suit specific needs and purposes.
Efforts have been made to improve
traditional cultivars. Donors with specific
characteristics have also been identified
from traditional varieties.
What are modern varieties?
Modern varieties are varieties developed as
genetically superior to traditional varieties
in yield and that have intermediate plant
type, better response to fertiliser and a
yield potential of more than 4 t/ha on
average. These varieties are also commonly
referred to as high-yielding varieties
(HYVs). Most modern varieties have been
developed through hybridisation.
Hybridisation and pedigree methods
Hybridisation is the crossing of two or more genetically unlike parents with
the desired characteristics. An F 1 seed is planted to produce the F 2 seed in
bulk. The F 2 seed is space-planted singly and selected individually (single
plant selection).
In the pedigree method, seeds from individual F 2 plants are sown in single-
row plots to form the F 3 generation. The seeds from the best plants of the
superior F 3 rows are harvested individually tu form F 4 lines. This process is
continued until the lines become uniform ( F 5 to F 7 ). The superior lines are
then bulk-harvested for testing in larger plots.
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