Euclidean distance can recognize the Biojas ® concentration that produces the ideal physiological status of pineapple "in vitro" plantlets

Biojas® is a fermented broth of Lasiodiplodia theobromae, a jasmonic acid-producing fungus characterized as a plant growth regulator and as biological control of phytopathogenic microorganisms and pests. The present work describes the use of Biojas® in in vitro culture of pineapple. On the other hand, plant scientists usually record multiple indicators in their experiments. The common statistical data evaluations involve univariate analyses such as t test Mann-Whitney, and analysis of variance (ANOVA) followed by Tukey's HSD. Such analyses do not evaluate integrally the effects of the experimental treatments because each indicator is analyzed independently. For this reason, we explored in this study the Euclidean distance combined with the data of the Biojas® treatment (0-2 mg l⁻¹ on pineapple in vitro plantlets as an integrating indicator. Plant height; number of leaves; D leaf length, width, and area; diameter of the plant base; fresh and dry weights of the plant; levels of chlorophylls; transpiration rate; CO₂ assimilation; and water use efficiency were recorded. Several statistically significant differences among Biojas® treatments were recorded. However, the most significant effects of Biojas® treatments were only noted in the plant height, length and area of D leaf, and water use efficiency. Variables mentioned above increased until 1.0 mg l⁻¹ Biojas® and decreased with high levels of Biojas®. Calculation of the Euclidean distance from each Biojas® level to the ideal physiological status of the pineapple plantlets revealed that 1.0 mg l⁻¹ Biojas® produced the pineapple plantlets with the best physiological status.