Journal of Crop Breeding

Extended Abstract
Introduction and Objective: Despite the importance of the eggplant, few breeding studies have been conducted in relation to this plant in Iran. Therefore, it requires more studies, especially in relation to the study of new lines and native genotypes of the country. The aim of this study was to character association and identification of direct and indirect effects of quantitative traits on yield in 40 eggplant lines at F4 segregating population.
Material and Methods: This experiment was performed in the research farm of Sari University of Agricultural Sciences and Natural Resources in the 2021 cropping season. In this study, 40 breeding lines in F 4 generation along with their parents were used. Traits studied in this study included plant height (centimeter), number of fruits per plant, fruit length (centimeter), fruit weight (gram), fruit diameter (millimeter) and fruit yield (gram / plant). In order to analyze the data, descriptive statistics, correlation, path analysis and cluster analysis were used. 
Results: The results of correlation showed that fruit yield had positive and significant relationship with fruit weight. Results obtained from path analysis indicated that fruit weight and after that fruit number in plant had greatest direct effect on fruit yield in eggplant. The greatest indirect effect of fruit weight is through the diameter of the fruit. These traits could be used as selection index for yield improvement in eggplant breeding programs. According to cluster analysis studied lines were grouped in three different clusters based on studied traits. 
Conclusions: Cluster analysis showed the existence of favorable diversity between the studied genotypes and grouped the studied lines in three different groups. Fruit weight and fruit number had greatest direct effect on fruit yield in eggplant. These traits could be used as selection criteria for yield improvement in segregating population of eggplant.