In vitro screening: The best method for salt tolerance selection among pistachio rootstocks

Abstract

Soil and water salinity are among the main limiting environmental aspects in crop production. This study has been done in order to find the most salt tolerant genotype among five candidate Pistacia vera L. genotype (Akbari, Ahmad-Aghaee, Italyayi, Badami, and Ghazvini) through the selection under in vitro condition. At the first step of salt tolerance selection, 40 shoots of each P. vera genotype were screened on Murashige-Skoog’s (MS) medium containing 120 mM NaCl in order to find the highest salt tolerant genotypes. At the second step of screening, the responses of seven selected P. vera single shoots (from the previous screening) and UCB-1 to three concentrations of NaCl (0, 60 and 120 mM) were investigated under in vitro condition. Increasing salinity level significantly reduced stem elongation, leaf number, fresh weight, starch, chlorophyll index and K+ content of pistachio genotypes. In contrast, the content of soluble sugars, proline, malondialdehyde (MDA), Na+ and Cl- significantly increased with increasing salinity level. Based on the PCA analysis, Akbari 2 with the lowest reduction in percentage of stem elongation (26%), fresh weight (37%) and starch content (24%) showed the highest performance under severe salt stress (120 mM). Moreover, the highest leaf number, proline, chlorophyll index and K+ content, as well as the lowest percentage of MDA, Na+ and Cl-, belonged to Akbari 2 under highest salinity level. The selected genotype can be mass propagated from one tolerant single plant of Akbari 2 via in vitro propagation.

Keywords

• Abiotic stress
• PCA
• Salinity
• Pistachio
• In vitro screening