Exploitation of Plum Genetic Diversity to Identify Soil-Borne Fungi Resistance Rootstocks

Abstract

High genetic diversity increases the chances of obtaining varieties resistant to abiotic stress in breeding programs. Plum rootstocks that are resistant to disease can be used for the propagation of various Prunus species. This research was conducted to evaluate different myrobalan plum genotypes and their resistance to three pathogenic bacteria, i.e. Rosellinia necatrix, Verticillium dahlia, Phytophthora cactorum. It was also endeavored to identify resistant genotypes, their degree of resistance to disease, and the correlation between their morphological traits. The experiment spanned from 2016 to 2018. In the first phase of the experiment, the morphological traits of 5 superior genotypes of myrobalan plum were evaluated. These genotypes were, namely, Ahmad-beigloo, Anar-1, 4835, 4813 and G14. In the second phase of the experiment, the genotypes were examined for their degree of resistance to the three mentioned pathogenic fungi. This was performed in two separate groups of complete randomized designs, with five treatments (genotypes) and nine repetitions. According to the results, the seedlings showed a high level of diversity with respect to morphological traits and features relating to the seed. Furthermore, under the influence of the Rosellinia fungi, as the length of the shoot and root increased, the length and percentage of the necrosis decreased. The Anar-1 genotype exhibited the longest necrosis and the highest percentage of necrosis which makes it the most susceptible genotype to the fungus in one group. The genotype Ahmad-beigloo exhibited the shortest necrosis and the lowest percentage of necrosis, making it the most resistant genotype to the Rosellinia fungus, and was placed in a separate group. With respect to the degree of seedling resistance to Phytophthora and Verticillium, there were no significant differences among the genotypes.