90 Papaya
in gynodioecious varieties. The yield variation in hermaphrodite plants is very high
and, as a result, this plant is not preferred (Ram 1995).
The seed production in papaya with 100% genetic purity is difficult because of
the dioecious nature of the plant. Therefore, the seed should be produced either
strictly under controlled conditions or in an isolated area. The breeder seed is,
generally, produced under controlled conditions. Under this method, the stigma
of female flowers is brushed with the pollen of male flower of the same variety
in dioecious varieties. While crossing female flowers, care should be taken that
stigma is not damaged. Only those flowers which are ready to open should be
selected in both the parents (Saran et al. 2014c). This avoids advance covering of
flowers against contamination with foreign pollen. Similarly, for producing seed
in gynodioecious varieties, the ready to open female flower should be crossed with
the pollen of hermaphrodite flowers/plant of the specified varieties in the same
way. Seed production by selfing hermaphrodite is much easier because the selected
flowers are only covered with glassine wax/butter paper. After crossing and self-
ing, it should be properly tagged for identification. Before starting seed produc-
tion of gynodioecious variety, knowledge of different types of flowers produced
by a hermaphrodite plant is essential. Generally, a hermaphrodite plant produces
five different types of flowers simultaneously; these are reduced elongate, elon-
gate, carpelloid elongate, carpelloid pentandria and pentandria. Except reduced
elongate, all the four types of flower are bisexual. The reduced elongate is uni-
sexual and produces only pollen. The fruit shape of hermaphrodite plant depends
upon the type of flower produced. The elongate flower produces a cylindrical- or
cucumber-shaped fruits while carpelloid elongate produces deshaped or cat-faced
fruit. The seed contents in these fruits are comparatively low. The pentandria and
carpelloid pentandria produce round to round oval-shaped fruits which resemble
the fruits of female plant.
Directives:
- Select the true to type trees (colour, yield, fruit shape, dioecious and her-
maphrodite) in the plantation of particular variety. - Cover the flowers with a bag once they form to ensure self-pollination in
hermaphrodite flowers. - Cover the flower buds with a bag once they start changing colour from light
green to yellowish on tip and just before opening or slitting in dioecious. - Similarly, the male flowers should also be covered before these open.
- Next day, carefully brushes the pollen collected from the covered male bud
or mature bud (just before opening) on female flower. - Mark these pollinated flowers.
- Fruits are collected at maturity or colour break stage.
- In breeding or seed production programmes of dioecious varieties, the male
plants are been tagged on the basis of ideotype/desired characters, namely,
flower colour, size, morphology, plant height, peduncle/petiole length, etc. - If desired male plant has been tagged for different traits, it should be main-
tained for more than one year.