inbreeding techniques. Inbreeding via self-pollination is the primary
process used for fixing the genetic background of papaya.
Papaya inbred lines derived from self-pollination parental backgrounds
require multiple generations to fix their genome as
homozygous. Classical breeding procedures to develop papaya
inbred lines are based on the inbreeding of segregating populations
or germplasm accessions. This strategy results in the selection
of pure lines through progeny testing, which can take up to 5–6
inbreeding generations (12 years on average), depending on the
genetic diversity of the background. The pure lines are then identified
among the progenies whose phenotypical segregation is
considered to be null. This methodology is expensive, laborious,
time- and space-consuming, and influenced by negative conditions
in the environment. However, Oliveira et al. (2010a) proposed a
procedure involving the use of microsatellite markers to select
homozygous plants indirectly, aiming to considerably reduce that
time in S2 and F3 generations. They found 11 lines with f = 1.00 and
18 lines with f varying from 0.95 to 0.96.