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. were analyzed for variation in the number of adventitious roots formed (hereafter referred to as rooting) on seedling hypocotyls in response to auxin treatment. 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 and reproductive growth parameters to determine correlated phenotypic effects of selection for rooting response. High rooting in HA correlated with compact, highly branched shoot growth. Genetic analysis of HA, Mt-0, and their F1, F2, and reciprocal backcross generations indicated that high and low rooting responses in this population may be controlled by several genes acting independently in additive-dominance fashion. Genetic variance partitioned into principally additive effects, with dominance favoring low rooting.