Indian Society of Genetics & Plant Breeding
The development of pistillate lines triggered the commercial
exploitation of heterosis in castor (Ricinus communis L.).
Pistillate lines were maintained conventionally by retaining
20 per cent monoecious or sex revertants as pollen source
resulting in high cost of rouging and low genetic purity
in certified hybrid seed production plots. Pistillate lines
when exposed to high temperatures (32°C) produce male
flowers in between female flowers or capsules called
interspersed staminate flowers (ISF). This environment
sensitive character, ISF, has been used in refined method
for the maintenance of pistillate lines in summer season
resulting in high genetic purity and less cost of rouging
in hybrid seed production plots. However, pistillate lines
have to be maintained in summer season exposing the
crop to seasonal difficulties viz., high temperature,
desiccating winds, poor irrigation resulting in low seed
set. An attempt has been made to isolate isogenic lines
of the pistillate line VP-1 to overcome such problems in
summer season. The F2 ratios of Pistillate x ISF indicated
the role of modifying genes in the expression of ISF.
Variants of (SF were classified as sparsely, moderately
and highly interspersed. The progeny of the sex variants
of ISF viz., sparsely and moderately interspersed ISF tend
to be pistillate while highly interspersed types produced
10-12 per cent plants with ISF
Keywords: Castor, pistillate and interspersed staminate flowers, VP-1.
Year: 2002
Volume: 62
Issue: 3
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906
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