Morphological effects of induced polyploidy in Dendrobium nobile Lindl. (Orchidaceae)

Mívia Rosa De Medeiros Vichiato,Moacir Pasqual,Marcelo Vichiato,Filipe Almendagna Rodrigues,Daniel Melo De Castro

doi:10.1590/1984-70332014v14n3a23

Abstract

In general, polyploidy in plants causes an increase in the size ofvegetative structures. This work aimed to compare diploid plants (2n = 2 x =38) and induced tetraploid plants (2n = 4 x = 76) of Dendrobium nobile Lindl. through the evaluation of themorphological characteristics of flowers, leaves and pseudobulbs. We evaluatedthe parameters height and diameter of pseudobulbs; width and length of leavesand flowers (sepals, petals and labella); and diameter of flowers. The inducedpolyploidization resulted in the increasing the number of internodes (19.9%)and floral pieces, with greater height of the flower (4.5%) and width of thelip (18.5%) decrease in the number of flowers per pseudobulb (40.9%) and thediameter of the pseudobulb (64.9%) and delayed flowering.

Highlights

IntroductionPolyploidy can produce desirable characteristics, which translate into increased floral parts, succulence degree, color a prominent position in the market potted plants
Dendrobium nobile Lindl., native herbaceous epiphyte of Southeast Asian of cultivation widespread in scientific circles, is considered the most orchid produced and marketed both in Brazil and in the world, occupying on breeding orchids due to the long cycle of plants in the Dendrobium genus, which leads to an average flowering development of three to four years.Polyploidy can produce desirable characteristics, which translate into increased floral parts, succulence degree, color a prominent position in the market potted plants
Genetic material Diploid D. nobile plants (2n = 38 chromosomes – witnesses and the treatments did not occur in polyploidization) and induced tetraploid plants (2n = 4x = 76 chromosomes) derived from the work of Vichiato (2007) were used, and these plants were cultivated in polyethylene pots (500 cm3) containing coconut fiber substrate that were maintained on countertops

Summary

Introduction

Polyploidy can produce desirable characteristics, which translate into increased floral parts, succulence degree, color a prominent position in the market potted plants Breeding programs for Dendrobium aim at obtaining plants for the market with desirable characteristics, for example, pseudobulbs with high vigor, upright flowers, a large number of flowers and variability of colors and floral pieces with larger sizes and widths of petals and/or sepals as well as greater durability of flowering, greater fertility and a decreased number of flowers per pseudobulb (Chaicharoen and Aejew 1981, Chaicharoen 1995, McConnell and Kamemoto 1993, Ketsa et al 2001, DaoLong et al 2012). There is a significant correlation between ploidy level and plant height of Dendrobium (Dao-Long et al 2012)

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