FROST-RESISTANCE OF SOME VARIETIES OF 2-ROW WINTER BARLEYS

Frost resistance of some varieties of two-row winter barleys (Labels, Pastoral, Famosa, Monaco, Kira, Magie, Colombo) was evaluated by the lethal temperature (LT(50)) in the vegetation period of 1992 to 1994 and compared with the control two-row variety Marinka and multi-row variety Lunet. Evaluated varieties according to the ascertained minimum lethal temperature had prevailingly lower frost resistant in the multi-row variety Lunet (LT(50) = -13.2 degrees C). Similar frost resistance was found in the varieties Pastoral (LT(50) = -13.4 degrees C) and Famosa (LT(50) = -12.3 degrees C). Lower frost resistance, on the level of the variety Marinka (LT(50) = -11 degrees C), Was recorded for the varieties Labela, Monaco, Kira. The lowest frost resistance was reported with varieties Magie and Colombo - these varieties are unsuitable for conditions of colder winters. Varieties sown at the end of September had higher frost resistance in comparison with varieties sown in the recommended time of sowing of multi-row barleys (20 September). Frost resistance was highest during the January sampling. At the autumn growth and development any differences were found out among varieties. Growth and development were affected by the date of sowing. According to the obtained results in frost tests varieties Pastoral and Famosa would be suitable for conditions of the Czech Republic. Varieties Labela, Monaco and Kira were more sensitive.