Niveles de Ploidía de plantas androgénicas de Aguaymanto (Physalis peruviana L.) asociado a caracteres citogenéticos y morfológicos

Abstract

La determinación del nivel de ploidía de plantas androgénicas es de importancia para la formación de híbridos dentro de las técnicas de mejoramiento genético de plantas. El presente estudio, realizado con 21 plantas androgénicas de aguaymanto (Physalis peruviana L.) tuvo como objetivos determinar la ploidía mediante técnicas citogenéticas (conteo de cromosomas con tinción DAPI y citometría de flujo) y caracterizar sus estructuras florales (Largo de gineceo, ancho de ovario, viabilidad de grano de polen, área de cáliz y corola) y morfológicas (largo, ancho y densidad de estomas; diámetro de grano de polen). A través del conteo de cromosomas y la citometría de flujo se evidenciaron diferentes niveles de ploidía: 71.42% fueron dihaploides, 23.80% tetraploides y 4.78 % hexaploides con 24, 48 y 72 cromosomas, los cuales, presentaron 6.29, 13.16 y 20.27 pg de ADN respectivamente. Asimismo, el largo (y=1.34x+16, r2=0.8624, p

The accurate identification of the ploidy level of androgenetic individuals is a critical point in plant breeding. Therefore, the aim of this study is to characterize 21 androgenic lines of aguaymanto through cytogenetic techniques (chromosome counting with DAPI and flow cytometry), stomatal parameters (length, width and density), morphological characterization at the floral level (Length of gynoecium, width of ovary, calyx and corolla area), diameter and viability of the pollen grain. Chromosome counting and flow cytometry revealed different levels of ploidy: 71.42% were dihaploid, 23.80% tetraploid, and 4.78% hexaploid with 24, 48, and 72 chromosomes and they also had 6.29, 13.16 and 20.27 pg of DNA content, respectively. Likewise, the length (y=1.34x+16, r 2 = 0.8624, p < 0.05) and width (y = 0.73x+14.74, r2 = 0.8882, p < 0.05) of the stoma increased significantly as the genome size increases. However, stomatal density (y=580.39-26.46x; r 2 = 0.7344, p < 0.05) was reduced significantly with respect to higher genome levels. Related to floral organs, a significant reduction was observed at 2x compared to 4x and 6x groups. However, the 6x group did not show statistical differences with 4x. At pollen diameter, the 6x group had a higher diameter than 2x and 4x groups. Finally, the best parameters that can be correlated with ploidy level are stomatal density, length and width of the stoma. However, chromosome count and flow cytometry need to be used when the plants were more developed.