Outcrossing rates and allozyme variation in rayed and rayless morphs of Bidens pilosa

Thirty-four isozyme loci were assayed in 1048 plants from three Hawaiian populations of the autogamous introduced weed Bidens pilosa. Total isozyme gene diversity was very low, 0-049. One population containing only rayless plants was completely monomorphic at all loci except PGI-3, and this locus was nearly fixed. In a large population polymorphic for rayed, rayless, and intermediate plants, two loci showed rare variants and PGI-3 was polymorphic. Allele frequencies at PGI-3 were not significantly different among the floral morphs, but outcrossing rates, measured by progeny tests using PGI-3 as a genetic marker, were significantly higher in the radiate morph (9 per cent) than in the rayless and intermediate morphs (5 per cent). Presumably radiate plants have higher outcrossing rates because they are more attractive to pollinators. © The Genetical Society of Great Britain.link_to_subscribed_fulltex

Genetics of gynodioecy in Hawaiian Bidens (Asteraceae)

Inheritance of male sterility in all gynodioecious species of Hawaiian Bidens was investigated by experimental crosses conducted in greenhouses. Both male-sterile individuals and hermaphrodites were segregated in the progenies of openpollinated female and hermaphroditic plants growing in nature. The ratios (H:MS) of 1:0, 1:1, 3:1 were observed in the F1 generations; 3:1 and 15:1 in the F2 generations; and 1:1 and 3:1 in the backcrosses. Thirteen interspecific triple crosses and all quadruple crosses gave MS progenies, indicating a directly allelic relationship among male sterility genes in all gynodioecious species. Based on these results, A digenic-cytoplasmic model was proposed, and the evolution of gynodioecy in Hawaiian Bidens was discussed. © The Oenetical Society of Great Britain.link_to_subscribed_fulltex

Early-inbreeding depression in Vaccinium myrtillus and V-vitis-idaea.

Fertility parameters were estimated in Vaccinium myrtillus and V. vitis-idaea after self- and cross-pollinations performed in growth chamber. We showed a drastic decrease in fertility after self-pollination as compared to cross-pollination. Number of plump seeds per berry was compared with previous field data. In both species, growth room conditions improved plump seed number after cross-pollination but not after self-pollination. In addition, in order to enhance resources supply to young developing fruits, cytokinin application was tested in V. myrtillus but no effect was detected. We hypothesize that the partial self-sterility is due to inbreeding depression based on the expression of recessive lethals