GENETIC-VARIATION FOR ANTHER CALLUS INDUCIBILITY IN CROSSES OF HIGHLY CULTURABLE WINTER WHEATS

Heritability studies suggest that variation among genotypes for callus inducibility should respond to selection. The objective of this study was to determine if crosses among parents with high callus initiation frequencies would produce segregation from which genotypes with improved callus inducibility could be selected. The winter wheat (Triticum aestivum L.) cultivars 'Centurk 78', 'Norstar' and 'Norwin' were chosen as parents, based on their high callus initiation frequencies and diverse parentage. F2 populations from crosses between each of these parents were evaluated for callus initiation frequencies and callus vigor as determined by growth rate and healthy appearance. Heterosis was detected for callus initiation in the 'Norwin' x 'Norstar' cross and for callus vigor in all crosses. Broad sense heritability estimates of 0.25 and 0.37 for callus initiation in the 'Centurk 78' x 'Norstar' and 'Norwin' x 'Norstar' crosses, respectively, suggest this trait can be improved by selection. Heritability estimates for callus vigor were less promising, ranging from 0.11 to 0.24.