Intraspecific variations in cardamom (Elettaria cardamomum Maton): assessment of genomic diversity by flow cytometry, cytological studies and ISSR analysis.

N Anjali,K K Sabu,K M Ganga,S Shefeek,F Nadiya

doi:10.1186/s40064-016-3226-x

N Anjali, K K Sabu + Show 3 more

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https://doi.org/10.1186/s40064-016-3226-x

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Abstract

Background The main goal of the work was to analyse intraspecific variation in Elettaria cardamomum Maton (cardamom) using genome size, cytological studies and molecular marker data. Nuclear DNA content and molecular marker details furnish data on genome size and genetic diversity respectively among the studied accessions and both complement each other for evolutionary and taxonomic studies.ResultsThe relative 2C genome size and total number of base pairs of cardamom was determined through flow cytometric analysis using propidium iodide staining. The nuclear DNA content was estimated in various sections of the species representing individuals from wild and cultivar genotypes following Zea mays L. CE-777 (2C = 5.43 pg) as internal reference standard. Chromosome number from growing root tip was examined following standard protocols. Twenty-six ISSR primers that generated polymorphic bands were used for genetic diversity analysis of the thirty accessions of cardamom. Estimated nuclear 2C DNA content ranged from 2.57 to 3.22 pg demonstrating 1.25-fold variation. The mean amount of 2C nuclear DNA of the cardamom was calculated as 2.87 pg which is equivalent of 2806 Mbp as the diploid genome size. The chromosome number was found to be 2n = 48. Among the thirty accessions of cardamom studied using ISSR markers, C53 (feral from Bonacaud) showed a very prominent level of genetic diversity and was lowest for C96 (Avinash-I, a released variety from Indian Institute of Spices Research, Kozhikode).ConclusionThese analyses revealed the existence of genetic variability within the studied cardamom accessions. The plant specimens also differed significantly in their genome size. However, the genetic variability parameters did not show any correlation with genome size.

Highlights

The main goal of the work was to analyse intraspecific variation in Elettaria cardamomum Maton using genome size, cytological studies and molecular marker data
Genetic diversity analysis using inter simple sequence repeat (ISSR) markers Twenty-six primers that generated polymorphic bands were used for genetic diversity analysis of the thirty accessions of cardamom (Table 4)
The present study focuses on intraspecific variation in cardamom with respect to genome size and ISSR data

Summary

Introduction

The main goal of the work was to analyse intraspecific variation in Elettaria cardamomum Maton (cardamom) using genome size, cytological studies and molecular marker data. Elettaria cardamomum Maton known as Queen of spices belongs to monocotyledonous family Zingiberaceae This perennial rhizomatous plant is mainly confined to mid-elevations (600–1300 m a.s.l.) in the Western Ghats of South India (Ravindran and Madhusoodanan 2003). Cardamom cultivation began during 1803 in India and until cardamom pods were harvested from forests (Ravindran and Madhusoodanan 2003) This means that selection of cardamom with respect to better agronomic traits began around 210 years ago. The cultivation was usually practised in forests after clearing all the undergrowth where cardamom grows naturally These processes could have gradually eliminated wild cardamom as such and genetic variations there exist. As in the case of other crop plants, wild cardamom plants (including disease escapes (Venugopal 1999) from abandoned plantations) may have genetic variability and possess alleles that can be effectively used for crop improvement programmes

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