Genetic mapping and QTL analysis of horticultural traits in cucumber ( Cucumis sativus L.) using recombinant inbred lines.
A set of 171 recombinant inbred lines (RIL) were developed from a narrow cross in cucumber ( Cucumis sativus L.; 2n = 2 x = 14) using the determinate ( de), gynoecious ( F), standard-sized leaf line G421 and the indeterminate, monoecious, little-leaf ( ll) line H-19. A 131-point genetic map was constructed using these RILs and 216 F(2) individuals to include 14 SSRs, 24 SCARs, 27 AFLPs, 62 RAPDs, 1 SNP, and three economically important morphological [ F (gynoecy), de (determinate habit), ll (little leaf)] markers. Seven linkage groups spanned 706 cM with a mean marker interval of 5.6 cM. The location of F and de was defined by genetic linkage and quantitative trait locus (QTL) analysis to be associated with SSR loci CSWCT28 and CSWCTT14 at 5.0 cM and 0.8 cM, respectively. RIL-based QTL analysis of the number of lateral branches in three environments revealed four location-independent factors that cumulatively explained 42% of the observed phenotypic variation. QTLs conditioning lateral branching (mlb1.1), fruit length/diameter ratio (ldr1.2) and sex expression (sex1.2) were associated with de. Sex expression was influenced by three genomic regions corresponding to F and de both on linkage Group 1, and a third locus (sex6.1) on linkage Group 6. QTLs conditioning the number of fruit per plant (fpl1.2), the number of lateral branches (mlb1.4) and fruit length/diameter ratio (ldr1.3) were associated with ll. The potential value of these marker-trait associations (i.e., yield components) for plant improvement is portended by the relatively high LOD scores (2.6 to 13.0) and associated R(2) values (1.5% to 32.4%) that are affiliated with comparatively few genetic factors (perhaps 3 to 10).
Fazio
G
G
USDA ARS/Dept. of Horticulture, University of Wisconsin-Madison, Madison, WI 53706, USA.
Staub
J E
JE
Stevens
M R
MR
D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D018553:Cucumis sativus / Q000235:genetics*; D018744:DNA, Plant; D008040:Genetic Linkage; D005819:Genetic Markers; D010641:Phenotype; D030821:Plants, Genetically Modified; D012150:Polymorphism, Restriction Fragment Length; D040641:Quantitative Trait Loci; D019105:Random Amplified Polymorphic DNA Technique; D012091:Repetitive Sequences, Nucleic Acid
D018744:DNA, Plant; D005819:Genetic Markers