Title

Desarrollo de un protocolo de duplicación cromosómica en híbridos intergenéricos helianthus annuus x tithonia rotundifolia

Author

BRICIA ANAYANKY BARRERA ROMO

Contributor

MANUEL HUMBERTO REYES VALDÉS (Thesis Adviser)

LETICIA ESCOBEDO BOCARDO (Thesis Adviser)

FRANCISCA RAMIREZ GODINA (Thesis Adviser)

Access level

Open Access

Summary or description

"El cruzamiento intergenérico entre Helianthus annuus y Tithonia rotundifolia produce híbridos estériles debido a incompatibilidad cromosómica. El objetivo del presente trabajo fue restaurar la fertilidad del híbrido a través del uso de colchicina para generar tetraploides. Para lograr esto se realizaron tratamientos preliminares con los progenitores mediante la exposición de meristemos a la colchicina a distintos tiempos (2, 5, 12, 20, 24, 30, 40 y 72 h) y a distintas concentraciones (10, 20, 100, 150, 200 y 250 mg L-1). A partir de las observaciones mitóticas de ambos progenitores mediante el método de aplastado, se determinó que el mejor tratamiento fue de 200 mg L-1 durante 5 h con un 36 % de células tetraploides, sin embargo todos los tratamientos mostraron mosaicos, situación que probablemente originó el restablecimiento del nivel diploide en los progenitores, comprobado mediante análisis meiótico en diacinesis. En conclusión la obtención de plantas tetraploides en los progenitores no fue posible bajo los tratamientos probados en este estudio, debido a un efecto parcial de la colchicina aplicada en ápices radiculares, que produjo mosaicismo en los tejidos."

"Chromosomal duplication with colchicine is one of the main methods for restoring fertility in hybrids derived from intergeneric and interspecific crosses, because these types of hybrids usually have abnormalities in the meiotic chromosome pairing. These abnormalities occurred in the intergeneric cross between Helianthus annuus and Tithonia rotundifolia, which produced sterile hybrids. viii The aim of this study was to test different treatments with colchicine in meristems to obtain tetraploid in progenitors of the intergeneric hybrid Helianthus annuus x Tithonia rotundifolia and then apply the best treatment in the hybrid to restore its fertility. The best treatment was colchicine at a concentration of 200 mg L-1 for 5 hours with 36 % of tetraploid cells in mitosis. After 5 hours this percentage decreased and 4x and higher polyploids increased. However, in all treatments mosaicism was induced which probably caused the restoration of the diploidy level, found by analysis meiotic chromosomal in diakinesis with 17 bivalents. Also, high concentrations of colchicine caused a decrease in pollen viability, probably due to changes in plant physiology. No significant statistical differences were observed in both species that could indicate an increase in ploidy level, as it has been detected in other species wich colchicine-induced duplication."

Publish date

December, 2010

Publication type

Master thesis

Publication version

Published Version

Format

application/pdf

Language

Spanish

Audience

Students

Researchers

Source repository

Repositorio Digital CID-UAAAN

Downloads

1391

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