The hybrid nature of Lycium ciliatum × cestroides (Solanaceae): experimental, anatomical, and cytological evidence

Abstract

The hybrid nature of Lyciurn ciliaturn x cestroides Hieron. is supported through experimental crosses. Using L. ciliaturn Schlecht. as a female parent, 57% of crosses set fruit with hybrid seeds, whereas reciprocal crosses were unsuccessful. Seeds had a high germination rate (76%). F, plants obtained agree with the herbarium specimens previously cited as putative hybrid and with a living plant we found in C6rdoba (Argentina). Leaf, stem, and flower anatomy, karyotype composition, and chemical nectar composition were analyzed in the artificial and the natural hybrid. Results were . compared with similar data on the parental species. Most of the studied features were intermediate between those of the parental species, as supported by principal component analysis. The origin of this hybrid may be due to pollen transfer mediated by bumblebees that occasionally visit both parental species. The distribution of the parental species overlaps in a wide Chaco region showing no spatial, environmental, or external reproductive isolating mechanisms. Results indicate there is a hybrid breakdown in the progeny of the hybrid that would restrict the natural interspecific gene flow.RCsumC : Des croisements expkrimentaux confirment la nature hybride du Lyciurn ciliaturn x cestroides Hieron. En utilisant le L. ciliaturn Schlecht. comme parent femelle, 57% des croisements foment des fruits avec des graines hybrides alors que les croisements rCciproques ne fonctionnent pas. Les graines ont un pouvoir germinatif ClevC (76%). Les plantes F, obtenues concordent avec les specimens d'herbier prealablement cites comme prCsumCs hybrides, et avec une plante vivante trouvCe ti Cordoba (Argentine).L'anatomie des feuilles, des tiges et des fleurs, la composition karyotypique, et la composition chimique du nectar ont Ct C analysCes chez l'hybride naturel et artificiel. Les rCsultats ont Ct C comparCs avec des donnCes de m&me nature sur les espbces parentales. La plupart des caractbres CtudiCs sont intermkdiaires entre ceux des espbces parentales, avec confirmation par analyse en composantes principales. L'origine de cet hybride pourrait provenir du transfer? de pollen par les bourdons, qui visitent occasionnellement et consCcutivement les deux espbces parentales. La distribution de ces deux espbces se recouvre dans une vaste rCgioin de Chaco et ne montrent pas de mCcanismes d'isolement reproductifs spatial, environnemental ou externe. Les rksultats indiquent l'existence d'une rupture hybride dans la descendance de l'hybride, laquelle restreindrait le flux gCnique interspkcifique naturel.

Karyotype Studies in Lycium Sections Schistocalyx and Sclerocarpellum (Solanaceae)

“…Previous studies in other South American Lycium species from several sections (Bernardello et al, 1995;Stiefkens & Bernardello, 1996 indicate that although the taxa are morphologically different (Bernardello, 1986;Bernardello & Chiang-Cabrera, 1998), this was not accompanied by variation in chromosome morphology. However, earlier meiotic studies, which included a hybrid (Bernardello, 1982;Chiang, 1982;Bernardello et al, 1995), found normal formation of bivalents, suggesting that large inversions or translocations have not occurred. paracentric inversions or reciprocal translocations of segments of similar length; Stebbins, 1958) could have taken place, as these changes cannot be detected with the staining methods used.…”

Patterns of chromosomal evolution in the florally diverse Andean clade Iochrominae (Solanaceae)

“…A review of crossing experiments and interspecific homoploid hybridization in sympatric species of Ranunculus (Baltisberger and Hörandl, 2016), showed enhanced crossability of species with the same karyotype and strong crossing barriers between those with different karyotypes and concluded that karyotype evolution is a major driver of diversification. In Solanaceae, two species of Lycium with markedly different corolla shapes, but with the same karyotype formula, were able to cross, producing a hybrid with intermediate morphology (Bernardello et al, 1995). Species of Iochrominae are known for their capacity to produce fertile hybrids, which makes the group a popular for breeding and gardening.…”

Karyotypic studies in Lycium section Mesocope (Solanaceae) from South America

“…They have been examined eight South American species (BERNARDELLO et al 1995;BERNARDELLO 1996, 2000) and six Iranian species (SHEIDAI et al 1999). Thus, the goal of this work is to study the mitotic chromosomes of South American representatives of Lycium section Mesocope, with emphasis in qualitative and quantitative analyses of their karyotypes applying numerical techniques.…”