FROST-RESISTANCE OF SOME VARIETIES OF 2-R OW WINTER BARLEYS

Frost resistance of some varieties of two-row winter barleys (Labels, Pastoral, Famosa, Monaco, Kira, Magie, Colombo) was evaluated by the l ethal temperature (LT(50)) in the vegetation period of 1992 to 1994 an d compared with the control two-row variety Marinka and multi-row vari ety Lunet. Evaluated varieties according to the ascertained minimum le thal temperature had prevailingly lower frost resistant in the multi-r ow variety Lunet (LT(50) = -13.2 degrees C). Similar frost resistance was found in the varieties Pastoral (LT(50) = -13.4 degrees C) and Fam osa (LT(50) = -12.3 degrees C). Lower frost resistance, on the level o f the variety Marinka (LT(50) = -11 degrees C), Was recorded for the v arieties Labela, Monaco, Kira. The lowest frost resistance was reporte d with varieties Magie and Colombo - these varieties are unsuitable fo r 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 grow th and development any differences were found out among varieties. Gro wth and development were affected by the date of sowing. According to the obtained results in frost tests varieties Pastoral and Famosa woul d be suitable for conditions of the Czech Republic. Varieties Labela, Monaco and Kira were more sensitive.