CYTOPLASMIC MALE STERILITY AND VIRUS INFECTION IN CAPSICUM ANNUUM L.

抄録

Inoculation experiments with various viruses were performed with Capsicum annuum L. Plants were used with known cytoplasmic and genotypic characters concerning pollen fertility (Table 1). The results with a set of three F₁ hybrids, having identical genotypes for pollen fertility and identical genetic backgrounds, have revealed that it is the cytoplasm which is primarily responsible for the reduction of pollen fertility after infection by specific viruses.
Progeny tests have provided more evidence (Tables 2 and 3) indicating that pollen fertility in plants having (S) cytoplasm and Rfrf genotype, and should be pollen fertile, was reduced following infection with specific viruses.
It is concluded that a certain interaction between specific viruses and a particular cytoplasm (S) is responsible for the reduced pollen fertility. In other words, the specific cytoplasm (S) modifies the action of Rf-gene by interacting with specific viruses.
Since it is evident that a cytoplasmic entity reacts in this way with specific viruses, its nature and origin were discussed, and the following speculation was proposed. A cytoplasmic entity for male sterility in Capsicum could have originated from an exogeneous virus in the course of evolution followed by the loss of infectivity. Then it may be supposed to have arrived at a state of a kind of plasmon or plasmid of RNA nature.