THE ROLE OF PHYTOHORMONES IN RESPONSE TO TRANSFORMATION OF PEA LINES,DIFFERING IN SYMBIOTIC CHARACTERISTICS, AND THEIR HYBRIDS

This study investigated various morphogenetic processes following woun ding, exogenous phytohormone application and oncotransformation in pea lines differing in symbiotic characteristics. The pea lines varied in callus and root formation abilities on medium without phytohormones. Exogenous phytohormones (auxins and cytokinins) decreased the diversit y in callus formation but revealed genotypic diversity in shoot format ion. Callus, and especially shoot formation capacities decreased great ly after subculture; the effect of phenotype became more visible. Tran sformation with Agrobacterium wild-type strains appeared to be more ef fective inducing condition revealing contrasting differences between p ea genotypes in tumor- and root formation. Pea lines with atypical mor phogenetic responses to transformation were revealed. The existing dif ferences between lines for root and tumor formation allowed genetic an alysis of these traits. F-1 hybrids were uniform with segregation in t he F-2. The capacity for root formation was inherited as a dominant tr ait, but tumor formation was a recessive trait. Using exogenous phytoh ormones, phenocopies of the typical morphogenetic responses to transfo rmation were obtained. The results suggest an interdependence of these morphogenetic processes with the endogenous phytohormone balance as d etermined by plant genotype.