Impact of diverse exogenous hormones on parthenocarpy, yield, and quality of pepino (Solanum muricatum) in the Qinghai-Tibet plateau's natural conditions.

Pepino (Solanum muricatum), native to the Andes Mountains, requires exogenous hormones in its brief frost-free plateau environment to induce parthenocarpy and ensure yield.The effects of different plant growth regulators and application methods on pepino's growth, yield, and fruit quality were analyzed. Results showed that exogenous plant growth regulators had significant effects on various plant traits For instance, plant height decreased by 43.56% in the flower dipping treatment with 40 parts per million (ppm) 2,4-Dichlorophenoxyacetic acid (2,4-D), while stem diameter decreased by 21.6% with 40 ppm 4-Chlorophenoxyacetic acid (4-CPA) spraying, indicating a notable inhibition of vegetative growth. In contrast, reproductive growth improved, with the 20 ppm 2,4-D spray treatment boosting yield by 627.06% compared to the control. Furthermore, the 30 ppm 2,4-D spray produced the highest single fruit weight, a 69.16% increase over the control. However, exogenous hormones also caused fruit cracking, with the highest rate (55.5%) in the 20 ppm 2,4-D spray treatment. As for fruit quality, glucose content decreased, while fructose and sucrose levels significantly increased in hormone-treated fruits compared to the control. No significant differences were observed in flavonoid, total phenol, or vitamin C content. Transcriptome sequencing showed that 16,836 genes were significantly downregulated in pepino flower buds 72 h after a 30 ppm 4-CPA spray. KEGG enrichment analysis suggested that 4-CPA regulates parthenocarpy by influencing amino acid and protein synthesis pathways. Applying plant growth regulators in different concentrations and methods significantly impacts pepino's growth, yield, and fruit quality. These findings could guide other crops facing similar environmental challenges and potentially transform agricultural practices in high-altitude regions.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-024-01533-7.