130 Papaya
Average deformed seeds/fruit (+++) was significantly higher rated in February
harvest as compared to fruits harvested in other months, while average vivipary
seeds/fruit (+++) was observed significantly higher during May harvested fruits. The
maximum incidence of vivipary and white seed disorders were observed during May
(13.4% and 75.7%, respectively), while least incidence was observed in February and
March (10% and 5%, respectively) (Figure 11.5). The highest economic loss (Rs.
53,600/ha) was observed in April, while the lowest during February (Rs. 16,800/ha)
in autumn sown crop of Pusa Dwarf for seed production (Saran et al. 2013a, b, c, d)
(Fig u re 11.6). In vitro culture study was conducted for maintenance or conservation
of such native diversity (Saha 2007).
11.4.1 Management
Papaya is a tropical crop and requires 23°C average daily temperature for 6 months
from flowering to fruit maturity. However, fluctuation of temperature, especially
higher temperature in subtropical areas of India is very high, so it is suggested to
avoid the susceptible cultivars and new plantation should be raised of resistant/toler-
ant cultivars under tropical area. Further studies are required to determine the exact
causes and management of this disorder.
11.5 Frost Damage
Low temperature is one of the most important environmental factors, which affect
the plant growth and productivity. The winter temperatures will never go below
7°C during December to February but temperatures can vary greatly depending on
regions. The leaves on affected plants start drying and petiole remain green; some
time (Fig u re 11.7).
402008–09 2009–10 2010–11 2011–12 2012–13
26
24
22
20
18
16
14
12
10
8
6
4
2
038
36
34
32
30
28
26
24
22
20
18
16
14
12
Maximum temperature (°C)Vivipary (%)10
8
6
4
2
0
December JanuaryFebruary
MonthMarch AprilMayFIGURE 11.5 Relationship between monthly maximum temperature and vivipary in cv.,
Pusa Dwarf.