Physiological Disorders 129
with the water deficit. The hermaphrodite varieties when exposed to very low and
high temperature, high humidity and nitrogen level, the male parts (stamens) trans-
form to carpel-like structure and form severely deformed fruit. The adoption of irri-
gation amount of 120% of evapotranspiration (ET) minimised the losses caused by
production of imperfect flowers.
11.3 Lumpy Fruit
Hard portions of tissue are frequently encountered in the flesh of ripe papaya fruits.
This disease of unknown origin, found in orchards on the island Oahu (Hawaii)
and subtropical parts of India, is referred to as ‘lumpy’ fruit. There are three types
of symptoms, namely, large plate like areas in the fleshy portion of the fruit, small
grain like lumps and rounded hemi-spherical lumps attached to the rind (Eloisa et al.
1994). Lumps can be artificially induced in papaya fruit by injections of a variety of
chemicals including water, indole acetic acid (IAA) and maleic hydrazide (MH), or
by physical injury. The presence of lumps in fruit can only be determined after the
fruit is fully ripened.
11.4 Vivipary and White Seed
Vivipary and white seed (disturbed sarcotesta) are major seed production constraints
of papaya in subtropical fringes of India. The precocious germination of seeds was
observed in fruits of papaya cv., Madhubindu while they were still attached to the
parent plant. The natural occurrence of precocious germination has been reported
in papaya (Balakrishnan et al. 1986). These disorders are emerging physiologi-
cal anomalies due to temperature fluctuation during seed and fruit maturity stage.
Morphologically, the normal fruits and seeds are entirely different from disordered
fruits (Figure 11.4).
FIGURE 11.4 (See colour insert.) Vivipary in cv., Pusa Dwarf.