The influence of paternal species on the origin of callus in anther culture of Solanum hybrids.

Stamen culture of several Solanum species and interspecific hybrids was performed and each stamen was scored for presence and origin of callus. Each species and hybrid has a characteristic callus growth pattern - either no growth (0), callus growth from the filament (F), or callus growth from the anther (A). Characteristic growth types of the interspecific hybrids indicate that callus growth takes precedence over no growth. Hybrids between F and A species exhibit mainly paternal passage of either characteristic callus type. Possible explanations for this pattern of inheritance are male plastome factors or imprinting of paternal genes. The latter explanation is presently preferred.