Plastid inheritance in Pisum sativum L.

Cultivar variability for levels of plastid DNA (cpDNA) in the germ cell line of germinated pea pollen has suggested the possibility of biparental plastid transmission. In order to examine this possibility further, RFLP markers were used to follow the transmission of cpDNA from parents to their F1 offspring. Results from these inheritance studies clearly indicate the presence of only maternal plastid markers in the F1 progeny of each cross examined, irrespective of the pollen cpDNA levels of the paternal parent. The same result is obtained for F1 progeny produced from crosses using pollen characterized by comparatively high cpDNA content, even when offspring are sampled at early developmental stages. Thus, there appears to be little correspondence between pollen cytological data indicating potential paternal plastid transmission and data from molecular marker studies confirming that P. sativum generally follows a uniparental-maternal mode of plastid inheritance. Insufficient F1 progeny were examined to exclude instances of trace biparentalism.