| Sumario: | reduce costs and labor associated with
predicting the genotypic mean (GM) of a synthetic
variety (SV) of maize (Zea mays L.), breeders
can develop SVs from L lines and s single
crosses (SynL,SC) instead of L+2s lines (SynL).
The objective of this work was to derive and
study formulae for the inbreeding coefficient (IC)
and GM of SynL,SC, SynL, and the SV derived
from (L+2s)/2 single crosses (SynSC). All SVs
were derived from the same L+2s unrelated lines
whose IC is FL, and each parent of a SV was
represented by m plants. An a priori probability
equation for the IC was used. Important
results were: 1) the largest and smallest GMs
correspond to SynL and SynL,SC, respectively;
2) the GM predictors with the largest and
intermediate precision are those for SynL and
SynL,SC, respectively; 3) only when FL=1, or m is
large, SynL and SynSC are the same population,
but only with SynSC prediction costs and labor
undergo the maximum decrease, although its
prediction precision is the lowest. To determine
the SV to be developed, breeders should also
consider the availability of lines, single crosses,
manpower and land area; besides budget, target
farmers, target environments, etc.
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