Effect of Glycine Betaine and Glutamic Acid on the Growth and Yield of Poblano Peppers (Capsicum annuum L.)

• DOI: https://doi.org/10.22533/at.ed.0973622601041

• Palavras-chave: biostimulation; cumulative yield; fruit biometry

• Keywords: biostimulation; cumulative yield; fruit biometry

• Abstract:

  The effect of exogenous application of glycine betaine, glutamic acid, and their combined application on vegetative growth, flowering, fruit biometry, and cumulative yield of Poblano chili peppers (Capsicum annuum L.) grown in a greenhouse was evaluated. The experiment was conducted in Tlajomulco de Zúñiga, Jalisco, Mexico, using a completely randomized block design with four treatments, three blocks, and 108 experimental units. The treatments consisted of glutamic acid, glycine betaine, their mixture in equal proportions, and an absolute control, applied at 1.5 g L⁻¹ via foliar and/or root application. Plant height, stem diameter, and number of flowers were analyzed using repeated measures models; the number of leaves, cumulative yield, and fruit biometry were analyzed using ANOVA and MANOVA. Plant height showed a significant effect of treatment (F = 66.51; p < 0.0001) and of the day × treatment interaction (F = 21.86; p < 0.0001), with the highest final height observed in the glycine-betaine treatment (76.74 cm), followed by glutamic acid (70.15 cm). The number of flowers also responded to treatment (F = 17.68; p < 0.0001) and to the day × treatment interaction (F = 11.28; p < 0.0001), and glycine-betaine achieved the highest final mean (23.63 flowers). Stem diameter showed no significant treatment effect (F = 1.74; p = 0.1633), and the number of leaves showed only a marginal trend (F = 2.63; p = 0.0539). For fruit, the treatment significantly affected weight (F = 26.56; p < 0.0001) and width (F = 7.59; p = 0.0002), but not length (F = 2.60; p = 0.0576). Glycine-betaine produced the highest fruit weight (54.38 g), the greatest width (5.04 cm), and the highest cumulative yield (105.92 g plant⁻¹), significantly outperforming the other treatments (F = 28.31; p < 0.0001). Under the conditions of this study, glycine-betaine showed the greatest biostimulant potential for improving the vegetative and reproductive performance of poblano chili peppers in a greenhouse.