Affiliation:
1. Agricultural institute, Stara Zagora, Bulgaria
Abstract
The new original egg laying lines T, P and N selected at the Institute of
Agriculture - Stara Zagora were used. Hybrid ?? ? ??, ?? ? ?? crosses were
obtained and used for paternal line. Thereafter, the following breeding
schedule of paternal and maternal lines was applied: Group I - (?????)? ?N?;
group ?? - (?????)? ?N?; group ??? - ???N?; and group ?V - ???N?. The
production traits of original and hybrid birds were recorded: live weight at
the age of 8 and 18 weeks, age of sexual maturity in days, 150 days egg
production, average egg weight - at 2-week intervals until end of lay;
livability, heterosis effect. The live weights of hybrids at 8 and 18 weeks
of age were statistically significantly lower compared to original lines. The
values of heterosis for this parameter were negative for all four hybrid
combinations. The earliest beginning of egg lay occurred in (?????) ? ?N?
(162.08 days of age) and ???N? (163.11 days of age). The relative (%)
heterosis for age of sexual maturity of studied hybrid combinations had
moderate to low negative values. Average egg weights of hybrids were higher
and the values of heterosis - positive for all four groups varying from 0.97%
to 1.63%. The average 150 days egg production was lower in purebred lines
compared to hybrids. The highest average 150 days egg production was
determined in ???N? hybrids - 142 eggs. The heterosis effect for egg
production in hybrids was significant.
Publisher
National Library of Serbia
Cited by
7 articles.
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