Dobroudja Agricultural Institute, BG- 9525 General Toshevo, Bulgaria
TSENOV, N., 2005. Combining ability of some bread wheat varieties for ear emergence time. Bulg. J. Agric. Sci., 11: 677-686
The regularities of inheriting the trait date to ear emergence were followed under field conditions. In a top-cross scheme involving two early varieties, the combining ability of a group of varieties with different vegetation period was investigated. It was established that date to ear emergence is controlled by an additive-dominant genetic system with prevalence of additive effects. The investigated varieties had different combining ability although their vegetation period was similar. The conclusion was drawn that the suitability of each individual variety in breeding for earliness has to be studied, as in the breeding for all other characters. The value of General Combining Ability (GSA) in the greater part of the investigated accessions correlated positively with their earliness as expressed by date to ear emergence. An exception in this respect was line 407-1; its high breeding value was due to the high effect of its Specific Combining Ability (SCA). The varieties Dropia, Sadovo 1 and Bolyarka can be used as good combinators for earlier date to ear emergence.