ANATOMICAL ASPECTS OF HYBRID EMBRYO ABORTION IN THE GENUS LENS L

Hybrid embryo abortion at about 14 days after pollination (DAP) is typical of crosses between the cultivated lentil, Lens culinaris, and the wild species L. ervoides, regardless of the direction of the cross. Hybrid embryo abortion was also observed in crosses between the cultivated lentil and specific accessions of its wild progenitor, L. orientalis, and between these accessions and L. ervoides. The embryos of the parental lines of these three taxa reached the globular stage ca. 5 DAP; the cotyledons, shoot, and root primordia were observed ca. 10 DAP, and the immature seeds reached their final size ca. 14 DAP. The embryos were surrounded by a thin layer of endosperm that disappeared when the immature seeds reached their final size. The development of the hybrid embryos and endosperm was similar to that of the parental lines up to the globular stage; after this stage retarded development and progressive necrosis were detected. At 14 DAP the hybrid embryos contained smaller cotyledons, initiations of shoot and root primordia, and remnants of the endosperm. Through the use of embryo culture hybrid embryos can be grown into vegetatively normal plants that are partially fertile. The genus Lens is therefore proposed as a model system for the genetic analysis of hybrid embryo abortion.