Unlike most genera in the early-divergent angiosperm family Annonaceae, Pseuduvaria exhibits a diversity of floral sex expression. Most species are structurally andromonoecious (or possibly androdioecious), although the hermaphroditic flowers have been inferred to be functionally pistillate, with sterile staminodes. Pseuduvaria presents an ideal model for investigating the evolution of floral s...

The crucifer family includes self-incompatible genera, such as Brassica, and self-fertile genera, such as Arabidopsis. To gain insight into mechanisms underlying the evolution of mating systems in this family, we used a selective comparative mapping approach between Brassica campestris plants homozygous for the S8 haplotype and Arabidopsis. Starting with markers flanking the self-incompatibilit...

Breeding programs aimed at conserving genetic diversity in populations of wildlife or rare domestic breeds rely on detailed pedigree analysis for selection of breeders that will minimize the loss of alleles, reduce the accumulation of inbreeding, and maintain gene diversity. Commonly, techniques use a matrix of kinship coefficients to derive measures of genetic variation, inbreeding, and the va...

In monoecious plants, gametes can be exchanged in three ways: among unrelated genets (outbreeding), with close relatives (inbreeding), or within individuals (geitonogamous selfing). These different mating systems may have consequences for population demography and fitness. The experiment presented herein used artificial crosses to examine the mating system of Chesapeake Bay, Virginia, USA eelgr...

The pollination ecology of Eremosparton songoricum (Litv.) Vass., a rare desert species endemic to central Asia, was examined by a series of observational studies and manipulative experiments in two natural populations during 2007–2008. Results showed that the duration of flowering lasted 21 and 23 days, respectively, in Populations A and B from late May to late June in 2008. Anthesis of a sing...

The degree to which stigmas are exserted above the stamen in flowers is a key determinant of cross-pollination (and hence allogamy) in many plant species. Most species in the genus Lycopersicon are obligate or facultative outcrossers and bear flowers with highly exserted stigmas. In contrast, the cultivated tomato (Lycopersicon esculentum) bears flowers with flush or inserted stigmas promoting ...

The overall rate of self-fertilization can be viewed as the sum of two distinct processes: 1) self-pollination of all ovules in a flower (whole-flower self-pollination); and 2) self-pollination of some of the ovules in a flower, occurring together with outcrossing of the remaining ovules (part-flower self-pollination). In some situations these processes may be equated with different modes of se...

Insular pollination systems are more extinction-prone and vulnerable to invasive species than mainland ones. They often have plants with reproductive mechanisms allowing for self-compatibility low species-rich communities of pollinators. Here, we document different traits the tropical tree Guaiacum sanctum on two insular populations contrasting pollinator assemblages: Guánica in Puerto Rico ali...

The most common type of reproductive mutations observed in the soybean [Glycine max (L.) Merr.] are those that induce male sterility. The high frequency of occurrence of male-sterile mutations indicates that a number of genes influence the processes of microgametogenesis and microsporogenesis. The current knowledge of these mutations is summarized. The origins of male-sterile mutations, their i...