Screening of Citrus Rootstocks for Salinity Tolerance Based on Initial Growth Attributes and Leaves Proline Content

Abstract

Citrus fruit being a major horticultural crop consumed globally, is severely affected by issues related to biotic and abiotic stresses. Following stress effects, a research study was carried out to evaluate the morphological and physiological responses of citrus rootstocks to different levels of salinity stress. The seedlings of citrus rootstocks (‘Troyer’ citrange, Citrus volckameriana and Sour Orange (Citrus aurantium)) were treated with different salinity levels (0, 50, 100 and 150 mM NaCl). Salinity stress at the level of 150 mM NaCl, reduced plant height, number of leaves plant-1, stem thickness, leaf area, chlorophyll content, fresh and dry weight of both shoot and root, survival percentage significantly. In contrast, maximum toxicity symptoms and highest content of proline accumulation in the leaves were observed in plants subjected with 150 mM NaCl. Moreover, the tallest plants, highest number of leaves plant-1, stem thickness, chlorophyll content, leaf area, fresh and dry shoot weight, root weight, survival percentage, minimum toxicity symptoms and maximum proline accumulation were recorded in Sour orange rootstock compared to ‘Troyer’ citrange and Citrus volckamariana. From the research findings it could be concluded that growth performance of all citrus rootstocks diminished with the increased salinity levels from 0 to 150 mM NaCl. The rootstock Sour orange was found tolerant to saline condition while ‘Troyer’citrange proved to be highly sensitive under saline condition.