Correlation between geography and cytogenetic diversity in Pomegranate (Punica granatum L.) cultivars in Iran

Pomegranate (Punica granatum L.) is an important horticultural plant with several cultivated forms planted in different regions of Iran. Due to its economic importance, studies have been carried out to illustrate the genetic diversity at the chromosomal and molecular levels in different pomegranate cultivars growing in this region. This study analyzed chromosome pairing and B-chromosomes of 21 pomegranate cultivars and tried to investigate the effects of geographical parameters like altitude and longitude as well as elevation and the mean annual rainfall on cytogenetic diversity of these taxa. An ANOVA test revealed the presence of a significant difference for chiasmata and chromosome pairing among the cultivars, indicating their genetic differences. A positive significant correlation was observed between total chiasma frequency and terminal chiasmata, intercalary chiasmata and the mean number of quadrivalents. A significant positive correlation was observed between annual rainfall and the mean number of rod bivalents, while a significant negative correlation was found for the number of ring bivalents. Altitude did not show any correlation with the cytogenetic characters studied, but showed a significant negative correlation with the number of univalents. Longitude showed significant positive correlation with the number of ring bivalents and a negative correlation with the number of univalents and intercalary chiasmata. PCA analysis showed that both geographical and cytological features contribute greatly in the diversity observed in the pomegranate cultivars. The occurrence of multipolar cells and unreduced pollen grains were observed in some of the cultivars. A romã (Punica granatum L.) é uma planta hortícola importante com diversas formas de cultura plantadas em diferentes regiões do Irã. Devido à sua importância econômica, alguns estudos genéticos têm sido realizados para ilustrar a diversidade genética em ambos os níveis cromossômico e molecular em diferentes cultivares de romã que crescem neste país. O presente estudo considera as análises de pareamento cromossômico e cromossomo-B em 21 cultivares de romã e tenta investigar os efeitos dos parâmetros geográficos, como altitude e longitude, bem como a elevação e a queda de chuva média anual sobre a diversidade citogenética destes cultivares. O teste ANOVA revelou a presença de uma diferença significativa para quiasmas e emparelhamento de cromossomos entre as cultivares, indicando a sua diversidade gené