Heterochromatin and polyploidy in Opuntia Mill. (Cactaceae: Opuntioideae): implications for plant breeding

ABSTRACT

Despite the importance of polyploidy for the evolution of Opuntia, few researches have been focused to identify the ploidy of cultivars used in plant breeding programmes. We aimed to provide chromosome numbers, ploidy and heterochromatin band patterns of seven species and 24 cultivars from Opuntia, and investigate the relationship between phenotypic characteristics and ploidy in these species. All cultivars analyzed of Opuntia atropes, O. cochenillifera, and one cultivar of O. undulata are diploids, O. larreyi, one cultivar of O. stricta and two cultivars of O. undulata are tetraploids and all cultivars of O. ficus-indica, one cultivar of O. stricta and four cultivars of Opuntia sp. are octoploids. CMA/DAPI banding revealed the occurrence of terminal bands in all cultivars and pericentromeric bands in six cultivars. Polyploid species of Opuntia had superior mean values than diploid ones in relation to the cladode width, cladode length, cladode area, cladode thickness and plant height. Diploids had superior mean values than polyploids in relation to the number of cladodes. Polyploidy may be a useful tool for obtaining Opuntia cultivars with quantitative characteristics of interest.

KEYWORDS:

• Cytogenetic
• forage palm
• heterochromatin
• polyploidy
• semi-arid

Acknowledgements

We thank to Instituto Nacional do Semiárido (INSA) and Instituto Agronômico de Pernambuco (IPA) for their technical support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

We thank to Conselho Nacional de Desenvolvimento Científco e Tecnológico (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) - Finance Code 001 (process number: 88882.316773/2019-01) for financial support.