2.3. SSR data analysis
The software PowerMarker v.3.25 (Liu and Muse, 2005) was
used to estimate the observed heterozygosity (Ho), gene diversity
(He) values, and the inbreeding coefficient (f) in each inbred line
across loci. Ho is the proportion of heterozygous individuals in the
population. At a single locus, it is estimated as 1 − k
u=1Pluu. He is
defined as the probability that 2 randomly chosen alleles from the
population are different. An unbiased estimator of gene diversity
at the lth locus is
1 − k
u=1Plu2
/
1 − (1 + f/n)
, where f is the
inbreeding coefficient, which ranges theoretically from −1 to 1.
The PowerMarker package was used to estimate inbreeding
within the papaya inbred lines by calculating the Wright’s withinpopulation
inbreeding coefficient FIS, which is defined as the
correlation of alleles within individuals within population (Weir,
1996). The expectation-maximization (EM) algorithm to find the
maximum likelihood estimation (MLE) of FIS was used. In addition,
the within-population inbreeding estimates were calculated
for each locus and overall loci using the FSTAT computer program
version 2.9.3.2. (Goudet, 2001).
2