Self compatibility in garden Chrysanthemum: occurrence, inheritance and breeding potential

Abstract

Self compatibility (SC), which was found to occur only rarely in the normally self-incompatible (SI) hexaploid garden chrysanthemum, Chrysanthemum morifolium Ramat., was studied by making a series of self and cross pollinations in progenies of 3 different SC sources. SC was transmitted without exception in 15 F1 progenies from crosses between SC and SI plants. No maternal effects were noted in 10 F1. progenies from reciprocal crosses between SC and SI plants. Selfing or intercrossing of SC plants did not produce any large, uniformly SC progenies. Initial intercrosses between SC and SI plants suggested that SC might be controlled by a single dominant factor. Further crosses suggested that the inheritance of SC was more complex and could be associated with more than 1 gene or be modified by other genes such as the S-genes. Seed yield following self pollination in some progenies gave evidence of a clear separation into SC and SI classes while in other progenies the separation was not so distinct. The condition of pseudoself-compatibility was evident in progenies derived from selfing SC plants or crossing between SC plants. SC was used to produce large quantities of inbred seed which is now available for producing both I1 and I2 generations. By using SC parents, the combined self and cross compatibility was increased as compared to compatibility in progenies derived from SI-SI matings.

The mating system and genetic structure in a disjunct population of the seaside goldenrod Solidago sempervirens L. (Asteraceae)

“…Several examples demonstrate that self-incompatibility and inbreeding depression have not proven to be insurmountable barriers to the evolution of self-fertility (Davies and Young, 1966;Thompson and Taylor, 1966;Antonovics, 1968;Lefebvre, 1970;Ronald and Ascher, 1975;Rick et a!., 1979).…”

“…** Present Address: Department of Plant Sciences, University of Western Ontario, London, Ontario, Canada, N6A 5B7. Antonovics, 1968;Lefebvre, 1970;Ronald and Ascher, 1975;de Nettancourt, 1977;Wu and Jam, 1980;Kress, 1983). The few seeds set by a single colonizing individual may lead to a breakdown in the self-incompatible mechanism, providing that self-fertility is heritable and inbreeding depression does not prevent the establishment of seedlings from self-pollinated seeds (Schemske, 1983;Schoen, 1983).…”

“…The high frequency of self-fertility in some peripheral popu-lations of strawberry clover (Trfoliumfragferum) also may have evolved under conditions of low probability of cross pollination (Davies and Young, 1966). Observations on the inheritance of self-fertility in these and other species provide evidence for the evolution of self-compatibility under conditions which limit cross pollination such as low plant density and the lack of pollinators (Davies and Young, 1966;Thompson and Taylor, 1966;Antonovics, 1968;Ronald and Ascher, 1975). Colonization events may also be a factor contributing to a breakdown in the incompatibility mechanism of heteromorphic incompatible species (Glover and Barrett, 1986;Barrett, 1979).…”

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

“…High temperature environments may still be the best means of maximizing PSC expression in chrysanthemums (Ling et al, 1966;Drewlow et al, 1973;Ronald & Ascher, 1975a), as is the case with Trifolium hybridum (Townsend, 1966) and Raphanus sativus (El Murabaa, 1957). All PSC sources in chrysanthemum arose and continued to arise from SI plants and can be expected to be heterozygous (Ronald & Ascher, 1975b). IfPSC genes are recessive to SI, then selfing PSC genotypes (particularly high PSC) should produce 100% PSC progeny.…”

Inheritance in Chrysanthemum morifolium Ramat.

“…Those utilised were 72R-310, 73R-8 and 72R-310-1 x71-27-25, the parentages of which are given by Ronald and Ascher (1975). Four plants which combined yellow or bronze flower colour (carotenoid) and a prolific self-seeding capacity were selected from these seed progenies for further use.…”