ABSTRACT
Cacao
is a tree crop of high economic importance and the subject of several studies
aiming the genetic improvement of the species with the incorporation of
characteristics that are agronomically important to create superior genotypes.
In this context, this study aimed to characterize 22 genotypes of cacao for
sexual compatibility, which is a trait that is strongly associated with yield.
Additionally, we identify genotypes incompatible with clone TSH-1188 through
controlled intercrosses, due to the great importance of this clone in cocoa breeding. Fifteen genotypes
were characterized as self-incompatible and other seven as self-compatible,
considering the retention index (20%) of self-pollinated flowers. Nine genotypes
were characterized for the first time: CCN-16, COCA-3310, COCA-3370/5, EB-1017,
IMC-119, IMC-97, LCTEEN-37A, NA-45, and UF-612. Cacao genotypes showed flower
retention index ranging from
0.0% to 55.1% after 15 days of self-pollinations. The number of retained
flowers varied after self-pollination of
cacao genotypes at 1, 5 and 15 days after pollination. CCN-51, Catongo, CCN-10
and P-4B, were the genotypes with minor losses of flowers after 15 days of
pollination, while IMC-119 and TSH-516 had 100% of loss of flowers between 1 and 5 days after pollination. Moreover, the flower retention index 15 days
after cross-pollination with TSH-1188 ranged from 0.0% to 87.5% among the
tested genotypes. The results of cross-pollinations identified two genotypes
that are incompatibles, EB-1017 and IMC-119. This result is important for
future allelic studies of incompatibility in cacao, because it might indicate that these genotypes share the same
self-incompatibility allele(s). We conclude, therefore, that this study
enable the characterization of this
working collection of cocoa germplasm for sexual compatibility and this
information is important for subsequent crosses between cacao genotypes.