Quantitative genetics of stamen fertility in Spergularia salina (Caryophyllaceae)

Abstract

Heritability of stamen fertility was studied in Spergularia salina (Caryophyllaceae), a selfing annual that shows extensive phenotypic variation in stamen fertility. Variation within and among 70 maternal families, derived from plants representing two natural populations from Sweden, was used to estimate heritabilities of stamen fertility for each of the 10 stamen positions in the flower. The hierarchical design of the study allowed partitioning of variation among four levels of organization using nested analysis of variance. Heritabilities ranged from 0.27 to 0.65 for stamen positions in the antipetalous whorl of stamens and from 0.18 to 0.67 for positions in the antisepalous whorl. When stamen fertility was pooled across all stamen positions of a flower, the heritability was 0.73 in both populations. The nested ANOVA indicated that antipetalous stamen positions have comparatively higher proportions of among-family and among-population variation than the antisepalous stamen positions. Furthermore, highly significant genetic correlations exist between the two antisepalous stamen positions STA 2 and STA 8 and among the other eight positions but not so between these two groups. The relationship between tetraploidization and stamen number reductions in Caryophyllaceae is discussed. Key words: Spergularia salina, stamen fertility, stamen position, heritability, hierarchical analysis of variance, quantitative genetics.