Qtl analysis and marker development for precocious yellow and glabrous characteristics of summer squash (Cucurbita Pepo)

As squash plant is spiny, while squash producers are harvesting spines of plant causes deformation thus decreases quality under current circumstances. Fruits with the characteristics of precocious yellow transforms into yellow color earlier and let producers to harvest earlier leading and increase in productivity by increasing the ratio of female flower. Genotypes to be selected in this thesis aim to develop markers in the related features for the objectives of not decreasing quality without causing deformation of the fruit in the harvesting season with the characteristics of glabrous in new squash types for precocious yellow and glabrous characteristics and to increase early harvest and productivity for the types having precocious yellow color gene. In the study, for precocious yellow gene characteristics back crossing 3 (BC3) was used as recurrent and monogenic dominant type was discussed. For the glabrous (spineless) characteristics, monogenic recessive type which was used as recurrent in back crossing 5 (BC5) was discussed. CTAB protocol was implemented in the DNA purification of leaf sample analysis for the genotyping made in the study and SNP (Single Nucleotide Polymorphism) marker was used and it was realized by QTL (Quantitative Trait Locus) mapping method. In the phenotype observation, for precocious yellow characteristics the observation was made by looking at the color of the fruit epicarp and fruit stem. In the glabrous characteristics, leaf-stalk of the plant was observed. In the phenotype observation performed of F2 generation for glabrous and precocious yellow characteristics, the ratio of segregation was determined as 1: 2: 1. As a result of analysis performed in genotyping studies, the log10 value of the genes found in SQ-0002662 and SQ0002421 loci in the positions between approximately 20cM and 22cM in 2 SNP markers chromosomes for precocious yellow color was found to be approximately 70 and marker was developed accordingly In the QTL mapping performed, it was observed that there is Cp4.1Eg07840 potential candidate gene available in Chromosome E at a distance of approximately 70 kb (0-2 cM). It was observed that the candidate gene found resembled hairless (Glabrous-2) in Arabidopsis. KEYWORDS: CTAB, precocious yellow color, squash, molecular markers, QTL, SNP, glabrous, hairless.