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 BC 1 and BC 2 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 9 elite germplasm created to broadened genetic base of this market type.

Backcross Introgression of the Cucumis hystrix Genome Increases Genetic Diversity in U.S. Processing Cucumber

“…2)]. This is in contrast to studies of IBL in Beit Alpha and European Long cucumber (Delannay, 2009;Delannay and Staub, 2010) in which a subset of IBL deviated from the cluster of IBL present in graphical depictions after PCA. Nevertheless, extreme IBL for each trait did ordinate toward the exterior of the central cluster of IBL herein.…”

Marker-assisted backcross selection in an interspecific Cucumis population broadens the genetic base of cucumber (Cucumis sativus L.)

“…Evaluated at Hancock, WI in 2007. IBL inbred backcross line, RIL recombinant inbred line (Fazio et al 2003a), Sel individuals selected for genetic diversity by 24 molecular makers, NSel individuals not receiving marker selection Euphytica (2011) 178:261-272 263 during the summer of 2005 (Delannay 2009). Based on this field evaluation, 21 BC 1 P 2 lines (plants) were selected [designated BC 1 P 2 (Sel)] given their comparative fruit yield and quality over six harvests (i.e., base population for subsequent MAS or NSel).…”

“…Based on this field evaluation, 21 BC 1 P 2 lines (plants) were selected [designated BC 1 P 2 (Sel)] given their comparative fruit yield and quality over six harvests (i.e., base population for subsequent MAS or NSel). These selections were multiplied by stem cutting, grown in the greenhouse to produce healthy mature plants, and then genotyped with 24 DNA markers [8 mapped and 16 unmapped (Delannay 2009); see below]. Based on their comparative genetic diversity, 11 BC 1 genotypes were selected for crossing to elite lines WI 7023A (P 2 ) and WI 9-6A (P 3 ), the progeny of which were designated as BC 2 P 2 (Sel) and BC 2 P 3 (Sel), respectively.…”

“…The efficiency and effectiveness of selection during line and population development in cucumber can be increased through MAS (Fan et al 2006;Robbins and Staub 2009). In fact, backcrossing with concurrent initial molecular-based genotyping and selection for genetic diversity has proven useful in cucumber (Fan et al 2006;Delannay 2009;Delannay and Staub 2010a;2010b). Therefore, a study was designed that employed marker-assisted backcrossing to increase genetic diversity in C. sativus by introgression of the C. hystrix genome into elite breeding lines.…”

USDA, ARS Beit Alpha Cucumber Inbred Backcross Line Population

“…Therefore, a series of Beit Alpha inbred backcross lines (BC 2 S 3 ; IBL) were developed through MAS and phenotypic selection and released in January 2011 by the Agricultural Research Service, U.S. Department of Agriculture through its web-based documentation system (ARIS). Markers used in MAS were single sequence repeats (SSR), sequence characterized amplified regions (SCAR), and single nucleotide polymorphisms (SNP), in which their complete description is given in Delannay (2009) and Delannay and Staub (2010). This is the first public release of genetically diverse but highly inbred Beit Alpha germplasm.…”