TY - JOUR

T1 - Localization and overcoming of hybridization barriers in Delosperma and Lampranthus (Aizoaceae)

AU - Braun, P.

AU - Winkelmann, T.

N1 - Funding Information: We gratefully acknowledge financial support given by the German Federal Ministry for Economic Affairs and Energy within the framework of the program “Zentrales Innovationsprogramm Mittelstand (ZIM)” [KF2508005MD2]. We furthermore thank the Selecta One Group for providing valuable information and the plant material investigated in this study and Dr. Marcus Linde and Julia Schröter for their kind support in performing the AFLP analyses.

PY - 2016/9

Y1 - 2016/9

N2 - The large succulent plant family Aizoaceae offers an enormous diversity of growth forms and flower pigmentations as well as prevalent tolerance to drought. Although many family members have potential for a wider use as ornamental plants, directed breeding of midday flowers is still in its infancy and only few cultivars have been launched onto the market so far. Most probably, this fact can be ascribed to the presence of cross-incompatibilities. The present study aimed at localization of intra- and intergeneric hybridization barriers between different genotypes of the genera Delosperma and Lampranthus by pollen germination tests, fluorescence and DIC microscopy, in vitro culture of seeds and ovules, and AFLP analysis. Aside from distinct self-incompatibility, the analyses revealed that pollen tube growth towards the ovules was not inhibited, even after intergeneric pollinations. Cross-combinations within Delosperma seemed to be compatible to a high extent, while hybridizations of the investigated Lampranthus genotypes and intergeneric combinations were largely unsuccessful. Investigations of embryo sacs following wide crosses using ovule clearing and differential interference contrast microscopy revealed fertilization failures as well as abnormal early embryogenesis. Seedlings obtained after wide crossings, mostly exhibited partial or complete loss of chlorophyll causing frequent hybrid breakdown. We therefore conclude that hybridization barriers between the investigated midday flowers occur both pre- and postzygotically.

AB - The large succulent plant family Aizoaceae offers an enormous diversity of growth forms and flower pigmentations as well as prevalent tolerance to drought. Although many family members have potential for a wider use as ornamental plants, directed breeding of midday flowers is still in its infancy and only few cultivars have been launched onto the market so far. Most probably, this fact can be ascribed to the presence of cross-incompatibilities. The present study aimed at localization of intra- and intergeneric hybridization barriers between different genotypes of the genera Delosperma and Lampranthus by pollen germination tests, fluorescence and DIC microscopy, in vitro culture of seeds and ovules, and AFLP analysis. Aside from distinct self-incompatibility, the analyses revealed that pollen tube growth towards the ovules was not inhibited, even after intergeneric pollinations. Cross-combinations within Delosperma seemed to be compatible to a high extent, while hybridizations of the investigated Lampranthus genotypes and intergeneric combinations were largely unsuccessful. Investigations of embryo sacs following wide crosses using ovule clearing and differential interference contrast microscopy revealed fertilization failures as well as abnormal early embryogenesis. Seedlings obtained after wide crossings, mostly exhibited partial or complete loss of chlorophyll causing frequent hybrid breakdown. We therefore conclude that hybridization barriers between the investigated midday flowers occur both pre- and postzygotically.

KW - Albinism

KW - Delosperma

KW - Embryogenesis

KW - Lampranthus

KW - Pollen tube guidance

KW - Reproductive isolation

UR - http://www.scopus.com/inward/record.url?scp=84981507367&partnerID=8YFLogxK

U2 - 10.1007/s10681-016-1751-x

DO - 10.1007/s10681-016-1751-x

M3 - Article

VL - 211

SP - 255

EP - 275

JO - EUPHYTICA

JF - EUPHYTICA

SN - 0014-2336

IS - 2

ER -