Maternal Environment and Priming Agents Effect Germination and Seedling Quality in Pitaya under Salt Stress

Abstract

Lack of water and salinity are common problems in many parts of the world. Therefore, some types of cacti can present as promising crops. Therefore, the ability of cactus species to survive and adapt under natural stress conditions should be evaluated. The experiment was aimed at evaluating the effect of salt stress on germination and emergence of pitaya seeds obtained from different species (Hyloceresu undatus (Haw.) Britton and Rose and Hylocereus polyrhizus (Lem.) Britton and Rose), priming with plant growth regulators, namely salicylic acid (SA), oxalic acid (OA) and mepiquat chloride (MC). The experiment had a completely randomized design with a 2 × 4 × 3 factorial scheme corresponding to two pitaya cultivars (white- and red-fleshed), four NaCl concentrations (0, 2500, 5000 and 10,000 ppm), and three PGRs (150 ppm/MC, SA, OC). According to the results, the maternal environment of the seed was important in salt stress resistance, while seeds matured in the environment with red fruit flesh were more tolerant to salt stress. Although Pitaya species are relatively salt-tolerant, growth (about 30%) was significantly reduced above 2500 ppm and germination (about 45%) above 5000 ppm. Germination percentage stood out as the most important trait determining seed quality and had positive effects on the germination stress tolerance index (r: 0.63), seedling length (r: 0.74) and fresh seedling weight (r: 0.56). This is the first study of how maternal environment affects germination and seedling quality under saline conditions in Hylocereus. The results obtained may contribute to pitaya cultivation and breeding.

Keywords

• Cactaceae
• seed viability
• seedling quality
• salinity
• PGRs
• <i>Hylocereus</i> sp.