Combining Ability of Transgressive Segregates in Sugarbeets1

Transgressive segregation in an F2 generation for increased root size in sugarbeets (Beta vulgaris L,) indicates the presence of genes with additive effects which condition this character. These genes are probably not unique to the inbred parents of this F2. Seven interpollinated transgressive segregants produced heavier roots than an interpollinated random sample from the F2. However, the combining ability of these seven transgressive segregants was not different from that of an F2 random sample, or a less intensely selected group of 64 plants. This study indicates that individuals superior because of additive genes may have no better combining ability than a random sample from their parent population.