New Zealand Journal of Crop and Horticultural Science 21: 115-121 (1993)
Barriers preventing hybridisation of Lathyrus odoratus with L. chloranthus and L. chrysanthus
J. F. Herrick, B. G. Murray & K. R. W. Hammett

Abstract

Interspecific hybridisation of the sweet pea, Lathyrus odoratus L., with two yellow flowered relatives, Lathyrus chloranthus Boiss. and L. chrysanthus Boiss., was undertaken with the aim of transferring yellow flower colour into the sweet pea. Initial reciprocal cross pollinations of L. odoratus 'Original', with the two species, produced no viable seed, suggesting the presence of interspecific hybridisation barriers. Observation of events following further reciprocal cross pollinations confirmed the presence of hybridisation barriers which prevented the formation of hybrid embryos in all cross combinations except L. chloranthus x L. odoratus. Post-fertilisation hybridisation barriers subsequently prevented the maturation of such hybrid embryos. Further crosses using a range of sweet pea cultivars indicated varying degrees of impediment to hybridisation depending on the cultivar used. Prefertilisation hybridisation barriers which prevented the growth of foreign pollen tubes to the bases of styles were observed in L. odoratus x L. chloranthus crosses and reciprocal L odoratus x L chrysanthus crosses involving long-styled L. odoratus cultivars.

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