Genetic studies of self incompatibility in the garden chrysanthemum, Chrysanthemum morifolium ramat

Abstract

Self incompatibility was investigated in the hexaploid garden chrysanthemum, a member of Compositae. Nine sibling clones selected from a highly compatible cross were all self incompatible. 14.8% of the crosses between these sibs in diallel were compatible, but one sib, 67-111-42, accounted for 10 of the 12 compatible crosses. 67-111-42 was also more compatible than the remaining 8 sibs in crosses to other closely related plants. Crosses of the 9 sibs to 12 unrelated tester clones indicated that none were male or female sterile. Inbreeding via pseudocompatibility was successful in increasing homozygosity at the S loci. The percentage of compatible crosses obtained in 3 sib diallels of I 2 clones from crosses of 67-111-42I 1 plants approached that of the original 9 × 9 diallel, but no one individual accounted for most of the compatible crosses. It was possible to separate the 9 sibs into 9 incompatibility patterns from the pollinations made in this study. The evidence suggests that the self-incompatibility reaction in the garden chrysanthemum is sporophytic and involves more than 1 locus.

Inheritance of pseudo-self compatibility in self-incompatible garden and greenhouse chrysanthemums, Dendranthema grandiflora Tzvelv

“…Inhibition of the pollen tubes occurs at the stigmatic surface, reciprocal differences are found, and the SI reaction appears to be stable in this allohexaploid (Drewlow et al, 1973). This sporophytic SI system has at least three epistatic S loci (Stephens etal., 1984;Zagorski et al, 1983).…”

Rapid detection of genetic variability in chrysanthemum (Dendranthema grandiflora Tzvelev) using random primers

“…Chrysanthemum has a strong selfincompatibility system, thus causing many crosses between related or unrelated individuals to be unsuccessful. Usually only between 5 and 50 per cent of crosses between sibs in an F1 are compatible (Drewlow et at., 1973;Ronald & Ascher, 1975;Zagorski et at., 1983;Stephens et at., 1984). The genetics of the sporophytic self-incompatibility system is not completely resolved but probably several loci are involved (more than two) and there is dominance of alleles (Zagorski et at., 1983;Stephens et at., 1984).…”

Inheritance in Chrysanthemum morifolium Ramat.

“…Genetic studies in C. morfo1ium are made difficult by the paucity of simply inherited qualitative characters which have been so far identified, and by the presence of a sporophytic self-incompatibility system (Drewlow et a!., 1973 (Inhibitor) giving white or pink flowers (depending on whether anthocyanin pigment is absent or present), and with nulliplex forms being yellow or bronze (Langton, 1980;Jordan and ReimannPhilipp, 1983). Segregation ratios for this character in diverse crosses made during the course of routine breeding were analysed to determine the mode of inheritance (Jordan and ReimannPhilipp, 1983), but the results proved equivocal.…”