SELECTION FOR ALLELIC VARIANTS OF ALCOHOL -DEHYDROGENASE IN INBRED LINES AND HYBRIDS OF SUGAR-BEET

The effect of genotypic composition at the ADH1 locus, which controls allelic variants of alcohol dehydrogenase (ADH), on seed germination, tuber weight, and fertility was studied in inbred lines and hybrids of sugar beet. Inbred plants of genotype ADH1-SS, which have low ADH act ivity, were shown to die partly or entirely at germination. The lethal ity was increased by hypoxia. Mortality of hybrid seedlings with genot ype ADH1-SS was either much lower or absent; however, surviving ADH1-S S plants had lower tuber weight and fertility. The results are discuss ed with regard to the distribution of the ADH1-S allele in hybrids and cultivars of sugar beet and possible mechanisms of ADH-S lethal effec t during development.