Use of molecular markers aids in the development of diverse inbred backcross lines in Beit Alpha cucumber (Cucumis sativus L.)

Abstract

Beit Alpha cucumber (Cucumis sativus L.) is a Mediterranean fresh-market type with a relatively narrow genetic base. To broaden its base for plant improvement, 42 diverse accessions were compared employing a previously defined standard marker array to choose wide-based parental lines for use in backcross introgression. Inbred backcross lines (IBL) were developed by crossing Beit Alpha line ‘04HD5’ (De Ruiter Seeds, The Netherlands; recurrent parent) and PI 285606 (Poland; donor parent), and then selecting the most genetically diverse BC1 and BC2 progeny based on molecular marker profiles, followed by three generations of single-seed descent to produce 117 IBL. Molecular genotyping of IBL was then performed, and IBL were evaluated for days to anthesis, sex expression, pistillate flowers per node, lateral branch number, fruits per plant, fruit length, and fruit weight in the US, The Netherlands, Israel, and Turkey. Multivariate analyses and genetic distance comparisons indicate that IBL possessed considerable inter-line morphological and genotypic diversity. These diverse IBL will be useful in genetic studies and to evaluate Beit Alpha cross-progeny derived from IBL × elite germplasm created to broadened genetic base of this market type.