Inheritance and linkage relationships of isozyme loci in cucumber (Cucumis sativus L.)

Abstract

Genetic analyses were conducted among 18 provisionary isozyme loci in Cucumis sativus L. Fourteen loci demonstrated simple Mendelian inheritance while observed variation at four loci (Gpi2, Gr2, Pgm3, Skdh2) was determined not to have a predictable genetic basis. Joint segregation analyses among the 14 genetically predictable polymorphic loci resulted in the assignment of 12 loci to four linkage groups. Linkage groups contain the following loci: (1) Gr1, Pgm1, Idh, Pgd1; (2) Pep-pap, Mdh2, Mdh3, Gpi1; (3) Pep-la, Per4; (4) Pgd2, G2dh. Mpi2 and Mdh1 segregated independently. Recombination fractions for linked loci ranged between 0.051 (Pgm1-Idh) to 0.385 (Pep-la-Per4). Some practical applications of isozyme marker loci for cucumer improvement are discussed.

Cucurbits (Cucurbitaceae; Cucumis spp., Cucurbita spp., Citrullus spp.)

“…Two other key papers describing genetic control of and linkage relationships among loci responsible for isozyme variation are those of Knerr and Staub (1992) for C. sativus and Staub, Meglic, and McCreight (1998) for C. melo.…”

“…600 cM with an average distance between RAPD markers of 8.4 cM. Information from the Serquen, Bacher, and Staub (1997a) map was recently merged with other maps (Fanourakis and Simon 1987;Knerr and Staub 1992;Kennard et al 1994;Staub 1996a, 1996b;Horejsi, Staub, and Thomas 2000) to synthesize a consensus map containing 255 markers, including morphological traits, disease resistance loci, isozymes, RFLPs, RAPDs, and AFLPs spanning ten linkage groups (Bradeen et al 2001). The mean marker interval in this consensus map was 2.1 cM, spanning a total length of 538 cM.…”

Genetic Mapping and Molecular Breeding in Cucurbits

“…These classic genetic maps in cucurbit were first developed for cucumber in the 1980s. Cucumber genome was mapped using morphological markers (Fanourakis and Simon 1987;Pierce and Wehner 1990;Vakalounakis 1992), isozyme markers (Knerr and Staub 1992), or both (Meglic and Staub 1996). Some of these markers are listed in the cucumber gene list curatored by Todd Wehner (Xie and Wehner 2001).…”

“…Some of these markers are listed in the cucumber gene list curatored by Todd Wehner (Xie and Wehner 2001). With these classical markers, Fanourakis and Simon (1987) mapped 168 cM of the genome while Knerr and Staub (1992) mapped 166 cM, Meglic and Staub (1996) mapped 584 cM, and Vakalounakis (1992) mapped 95 cM. Considering the length of the cucumber genome is 750-1000 cM (Staub and Meglic 1993), these maps are far from saturated.…”

A genetic linkage map of cucumber (Cucumis sativus L) combining SRAP and ISSR markers

“…In their studies to identify linkage groups in cucumber, Knerr and Staub (1992) and Meglic and Staub (1996) assigned 12 and 17 loci respectively to four linkage groups. Their linkages spanned 215 cM and 584 cM, respectively.…”