The Mating System of the Wild-to-Domesticated Complex of Gossypium hirsutum L. Is Mixed

Abstract

The domestication syndrome of many plants includes changes in their mating systems. The evolution of the latter is shaped by ecological and genetic factors that are particular to an area. Thus, the reproductive biology of wild relatives must be studied in their natural distribution to understand the mating system of a crop species as a whole. Gossypium hirsutum (upland cotton) includes both domesticated varieties and wild populations of the same species. Most studies on mating systems describe cultivated cotton as self-pollinated, while studies on pollen dispersal report outcrossing; however, the mating system of upland cotton has not been described as mixed and little is known about its wild relatives. In this study we selected two wild metapopulations for comparison with domesticated plants and one metapopulation with evidence of recent gene flow between wild relatives and the crop to evaluate the mating system of cotton’s wild-to-domesticated complex. Using classic reproductive biology methods, our data demonstrate that upland cotton presents a mixed mating system throughout the complex. Given cotton’s capacity for outcrossing, differences caused by the domestication process in cultivated individuals can have consequences for its wild relatives. This characterization of the diversity of the wild relatives in their natural distribution, as well as their interactions with the crop, will be useful to design and implement adequate strategies for conservation and biosecurity.

In vitro performance in cotton plants with different genetic backgrounds: the case of Gossypium hirsutum in Mexico, and its implications for germplasm conservation

“…Regardless of the trait performance direction of populations (W T and D T ), we can argue that given the existent differences between D and W genotypes without transgenes (see above and Velázquez-López et al, 2018), it is expected that additional genetic changes (due to gene insertion) could contribute to increased phenotypic differentiation. Nonetheless, given that we did not determine the exact location of the inserted transgenes in the genome, it is not possible to give a mechanistic explanation to the specific trait differences.…”

“…2A–2E). Such phenotypic differentiation, regardless of substantial evolutionary divergence and genetic differentiation (Fang et al, 2017), is somehow unexpected, since differentiation between these populations is the result of a selective process focused on traits that are not related to in vitro performance, such as length, size and color of the fiber, loss of seed dispersal and germination speed (Lubbers & Chee, 2009; Gross & Strasburg, 2010; Velázquez-López et al, 2018). Nonetheless, strong selective forces associated with domestication and divergence times between populations are together of sufficient strength to show phenotypic differentiation even in an environment to which both W and D populations were naïve to ( in vitro conditions).…”

“…Mexico is the center of origin for cotton ( Gossypium hirsutum L.) (Ulloa et al, 2006; Burgeff et al, 2014), and its metapopulations have been found on the coasts of the country, while extensive cultivars can be observed in the northern states, and backyard/home garden plants and native varieties have been reported in the southeastern states (Velázquez-López et al, 2018). Previous studies have described the genetic diversity of the Mexican metapopulations, including the presence of transgenes in some of them (Wegier et al, 2011), suggesting gene flow associated with specific transformation events (i.e., transgene introduction) from extensive cultivars to metapopulations.…”

Impact of <i>Amegilla calens</i> and <i>Apis mellifera</i> Pollination on <i>Gossypium hirsutum</i> var. QR<sub>1</sub>302 Flowers at Tchabbal-Mounguel (Ngaoundéré, Cameroon)

“…Over 90% of the worldwide cotton production comes from cultivars of G. hirsutum [1]. It is one of the major cash crops cultivated in three Northern Regions of Cameroon [2].…”

“…Anthesis occurs in the morning, soon after the flowers are completely open, and the stamens begin to release pollen afterward [4]. The mating system of cotton has been the major topic of several studies; however, the majority of them have described it as predominantly autogamous and self-pollinated [1]. Flowers of G. hirsutum produce pollen and nectar that attract pollinators.…”