Genetic analysis of variation for auxin-induced adventitious root formation among eighteen ecotypes of Arabidopsis thaliana L-Heynh.

Eighteen ecotypes and two inbred lines of Arabidopsis thaliana L. Heynh. we re analyzed for variation in the number of adventitious roots formed (herea fter referred to as rooting) on seedling hypocotyls in response to auxin tr eatment. Mean root counts varied from 1.7 to 23.1. Stable high (HA) and low (LA) rooting lines selected from ecotype Columbia, a low rooting ecotype ( Mt-0), and unselected Columbia populations were evaluated for vegetative an d reproductive growth parameters to determine correlated phenotypic effects of selection for rooting response. High rooting in HA correlated with comp act, highly branched shoot growth. Genetic analysis of HA, Mt-0, and their F-1, F-2, and reciprocal backcross generations indicated that high and tow rooting responses in this population may be controlled by several genes act ing independently in additive-dominance fashion. Genetic variance partition ed into principally additive effects, with dominance favoring low rooting.