Morphological characterization of cos type lettuce (Lactuca sativa var. longifolia ) genetic sources

In this study, the morphological characterization of 28 cos lettuce (Lactuca sativa var. longifolia) genotypes collected from different locations in Turkey was performed in two periods (autumn and spring) according to the UPOV (International Union for the Protection of New Plant Varieties) and TTSM (Central Directorate of Seed Registration and Certification) plant variety trait document. In addition, the current level of variation in the population was determined. As a result of the research, phenotypic diversity was found to be quite high in terms of morphological identification criteria in local cos lettuce genetic resources. The average plant height of the plants belonging to the genotypes in the autumn period varied between 26.30 (YM-4) - 33.70 (YM-10) cm. The highest plant height was measured in YM-16 (34.00 cm) genotype, and the lowest plant height was measured in YM-25 (21.67 cm) genotype in the spring. The earliest bolting in autumn was recorded in the YM-28 genotype (24 days), and the latest bolting (51 days) was recorded in the YM-1, YM-5, YM-6, YM-7, and YM-16 genotypes. In the spring period, genotypes went into the bolting stage in 60-88 days. The highest bolting rate was recorded in the YM-28 (100%) genotype, and the lowest bolting rate was recorded in YM-1, YM-13, YM-16 and YM-19 genotypes at 12.5%. Principal component analysis and cluster analysis were applied to the data obtained as a result of morphological characterization. As a result of principal component analysis, 12 independent principal component axes were formed in the cos lettuce genotypes. It was found that the total variation in the cos lettuce population were 87.38%. In the thesis study, it was noted that the coefficients of the eigen values of the 12 main components, which are independent from each other, varied between 1.07 and 8.88. In addition, as a result of cluster analysis, a dendrogram showing the relative relationships of the cos lettuce genotypes was obtained. When the resulting dendrogram was examined, it was found that the genotypes of cos lettuce were distributed in 7 groups and 14 subgroups. It is planned to evaluate the local genetic materials of the cos type lettuce studied in this study in the future variety breeding studies.d