Evaluation of Genetic Diversity for Morphological and Physiological Characteristics in Squash Landraces from Northwest Iran

In order to evaluate genetic diversity among squash landraces from Northwest Iran by morphological and physiological traits، 18 squash landraces belong to pumpkin، ornamental and confectionary groups were planted in completely randomized block design with three replications in Agricultural Research Center of Urmia in 2013. Morphological characteristics related of fruit، seed، leave and flower and physiological characteristics such as photosynthesis rate، TSS and pH were investigated in the studied genotypes. The highest genetic coefficient of variation was observed for fruit yield and plant length. Most of the studied traits had moderate to high heritability. For characteristics such as fruit weight، fruit length، fruit yield and seed yield، the highest expected genetic advance was observed whereas in the cases of primary branching، leaf length، ratio of leaf length to width، flagpole diameter and length and anther length the lowest expected genetic advance was seen. The seven principal components explained approximately 86. 95% of total variance. In the first component، the contribution and importance of traits such as fruit weight، fruit width، internodes، primary branching، fruit yield، seed and 100 seeds weights، TSS، pH، fruit and peduncle lengths، male and female sepals lengths، skin thickness، seed to fruit weight ratio and net photosynthesis rate was high. Based of cluster analysis، the highest genetic distance in the confectionary group was observed between Kenar Burazh and Saatlou landraces، and in the pumpkin group it was observed between Khoy and Zayeh Kandi landraces.