COMBINING ABILITY OF SUNFLOWER PLASTOME M UTANT LINES AND EXPRESSION OF HETEROSIS FOR QUANTITATIVE TRAITS IN INTERMUTANT HYBRIDS

It was shown that distinct mutant plastomes determined significant dif ferences in general combining ability in chlorina lines and green reve rtants with identical nuclear genomes. Both positive and negative effe cts of mutant plastomes on GCA and SCA, depending on parental lines, c ross combination, and the trait analyzed, were demonstrated. The relat ionship between GCA and SCA and the manifestation of heterosis was stu died. Prevailing types of gene interactions, which cause heterosis for morphological characters in particular hybrid combinations, were reve aled. Several hypotheses on the possible mechanisms of plastome involv ement in expression of heterosis were advanced.