Leaf and root-growth characteristics contributing to salt tolerance of backcrossed pepper (Capsicum annuum L.) progenies under hydroponic conditions

Abstract

The aim of this study was to determine the genotypic differences in salt tolerance of third back-crossed peeper progenies and their respective parents through examining the changes in the shoot growth at agronomical, root growth at morphological and leaf development at physiological levels under salt stress. A hydroponic experiment was conducted by using an aerated Deep-Water Culture (DWC) technique in a controlled growth chamber of Erciyes University, Agricultural Faculty in Kayseri, Turkey. Five pepper plants (BC3-1, BC3-2, BC3-3, BC3-4, BC3-5) were selected from the third backcrossed (BC3) progenies of Sena and Kopan. Plants were grown in 8 L pots filled continuously aerated nutrient solution under at two electrical conductivity (EC) levels (control at 1.0 dS m−1 and salt at 8.0 dS m−1) in RBD design with four replications for six weeks. Significant reductions in leaf, shoot and root fresh and dry biomass productions, total leaf area, total root length, and total root volume of pepper plants were recorded under hydroponic salt stress. On the other hand, significant differences in salt tolerance among backcrossed peeper progenies and their respective parents existed. Particularly the progeny of BC3-3 was more tolerant characterized to salinity than the other progenies of third backcrossed and their respective parents. This was highly associated with vigorous root growth (root fresh and dry weight, total root length and volume) and photosynthetically active leaves (total leaf area, leaf chlorophyll index, chloride exclusion) under hydroponic salt stress. These traits could be useful characters to select and breed salt-tolerant pepper varieties for sustainable agriculture in the future.