Root development in F1 coffe hybrids obtained by tissue culture

Abstract

F1 Hybrid seedlings, obtained by indirect somatic embryogenesis, were acclimatizated under greenhouse conditions, separated in 2 types of container: biodegradable mesh with compressed turf (Jiffy®) and the other on conventional tray with soil and rice husk. Two months later, the plantlets were transferred to bags with conventional substrate and grown under nursery conditions. Development and quality of the plants were evaluated after growing during 8 months under conventional management. It was found that 33% had straight roots, however 65% had abnormalities, such as constrictions and loops, twists, bifurcations, among others, corresponding to lesser values in length, thickness and weight, both in the radical system as well as aerial. In regard to container type, acclimatizated plants grown in Jiffy® showed better growth than those in trays; however, those on which the cover was kept during the nursery stage were less developed, as compared to those were the cover was removed. It is recommended to remove the Jiffy® cover before planting in the soil bag in the nursery, and improve the temporary immersion technique to prevent morphological abnormalities of the embryos produced.

Plántulas de Híbridos F1 de café, obte- nidas por embriogénesis somática indirecta, fueron aclimatizadas bajo condiciones de inver- nadero, en 2 tipos de contenedores: bandeja con sustrato convencional y malla biodegradable con turba comprimida (Jiffy®). A los 2 meses, las plántulas fueron transferidas a bolsa con sus- trato convencional y desarrolladas en el vivero. Se evaluó el desarrollo y calidad de la planta 8 meses después de su crecimiento en almácigo. Se encontró 33% de raíces rectas y 65% con morfologías anormales como estrangulamien- tos, serpenteadas y bifurcaciones, las cuales tuvieron respectivamente menores valores en los parámetros de largo, grosor y peso, tanto en el sistema radical como aéreo. En cuanto al tipo de contenedor, se obtuvo mayor crecimiento en las plántulas desarrolladas en Jiffy® con res- pecto a las de bandejas, sin embargo, aquellas que preservaron la envoltura durante la etapa de vivero, tuvieron menor crecimiento y desarrollo, con respecto de aquellas que les fue retirado. Se recomienda retirar la cobertura del Jiffy® previo a la siembra en bolsa, así como mejorar la técnica de inmersión temporal para evitar anormalidades morfológicas en los embriones producidos.