PAPAYA - Tropical Fruits - page 292

Origin and distribution
C. papaya has not been found wild in nature and is only distantly related to
the Vasconcella species, based upon isozyme and AFLP analysis. The greatest
diversity in C. papaya exists in the Yucatan-San Ignacio-Peter-Rio Motagua
area of Central America. The volunteer population in this area has greater
diversity than domesticated populations (Morshidi, 1996; Van Droogenbroeck
et al. , 2002). Papaya origins are rather uncertain, but there is some agreement
among botanists that it originated in the lowlands of Central America, between
southern Mexico and Nicaragua. Early distribution over a wide geographical
region in Central and South America was aided by the abundance of seeds in
the fruit and the seeds long viability. The accounts of 18th-century travellers
and botanists indicated that seeds of papaya had been taken from the
Caribbean to Malacca and on to India (Storey, 1941a). From Malacca or the
Philippines, distribution continued throughout Asia and to the South Pacifi c
region. Don Francisco Marín, a Spanish explorer and horticulturist, is credited
with the introduction of papaya into Hawaii from the Marquesas Islands
during the early 1800s. Papaya is now grown in all tropical countries and in
many subtropical regions of the world (Anonymous, 2003).
ECOLOGICAL REQUIREMENTS
Major commercial production of papaya is found primarily between 23° N and
S latitudes. Man has extended cultivation into regions as far as 32° N and S.
At these latitudes, papayas may be best grown in well-protected areas at sea
level. In Hawaii, at l9-22° N, papaya is grown at sea level and up to 300 m
elevation.
Soil
Papaya can be grown on a variety of soil types, with the most essential
requirement being drainage. A porous loam or sandy loam soil is preferred.
In Hawaii, the crop is frequently grown on rocky, volcanic soil called a'a,
composed of porous lava with some organic matter and excellent drainage;
the planting holes are fi lled with soil prior to planting.
Soil pH should be between 5.0 and 7.0, with the range between 5.5 and
6.5 being more desirable (Awada et al. , 1975). At pH levels below 5.0, seedling
growth is poor and mortality high. In soils with a pH range of 5.0-5.5, lime
applications can increase growth and yield. Papaya can be grown successfully
on problem soils. For peat soils, high rates of lime application (6-8 t/ha) are
essential for cultivation. Micronutrients (boron, zinc and copper) are also