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Sex-determining and floating translocation complexes in Viscum cruciatum Sieber ex Boiss. (Viscaceae) in southern Spain. Some evolutionary and ecological comments

1993; Oxford University Press; Volume: 111; Issue: 3 Linguagem: Inglês

10.1006/bojl.1993.1025

1095-8339

Abelardo Aparicio,

Plant pathogens and resistance mechanisms

As in other dioecious species of Viscum, males of V. cruciatum always produce large rings of chromosomes during meiosis due to the existence of permanent translocation heterozygosity. Only rings often (and very rarely 12) chromosomes have been found in this species, probably a relative of V. album in the Mediterranean area. Females form bivalents. Another two floating translocations—not sex-associated and affecting different chromosomes—have been observed in both male and female plants in some populations. These produce meiotic configurations previously unrecorded in Viscum . This floating heterozygosity seems to be correlated with the aptitude of V. cruciatum to develop on different hosts, especially Prunus . All studied populations showed an excess of female plants, perhaps partly due to facultative agamospermy.