Open Access

ARTICLE

Cytogenetical Changes among Polyembryonic (PEm) and Non-PEm Maize Plants

by A. A. Román-Calzoncit¹, F. Ramírez-Godina^2,*, J. Sánchez-Laureano², A. C. Flores-Gallegos¹, J. Espinoza-Velázquez², R. Rodríguez-Herrera^1,*

1 School of Chemistry, Universidad Autónoma de Coahuila. Blvd. V. Carranza e Ing. José Cárdenas V. s/n. Col. República Ote. C.P. 25280. Saltillo, Coahuila, México
2 Plant Breeding Department, Universidad Autónoma Agraria Antonio Narro, Blvd. Antonio Narro 1923, Buenavista, Saltillo, México

* Corresponding Authors: F. Ramírez-Godina. Email: ; R. Rodríguez-Herrera. Email:

Phyton-International Journal of Experimental Botany 2021, 90(1), 87-97. https://doi.org/10.32604/phyton.2020.013880

Received 25 August 2020; Accepted 21 October 2020; Issue published 20 November 2020

Abstract

Polyembryony in maize (PEm) contributes to improving the nutritional properties of the grain, as well as an increase in yield, since it generates multiple plants per seed, opening the possibility of developing new varieties. However, it is unknown whether polyembryony in maize is the product of chromosomal abnormalities. Based on the above, in this research a cytogenetic study was proposed to verify if chromosomal abnormalities are related to the maize polyembryony. For a meiotic study, maize genotypes with variable proportions of polyembryony (PEm), from the UA-IMM-BAP population and non-PEm (monoembryonic) maize were used, while for a mitosis analysis, 30 families of maternal half-siblings (MHS) from two different populations with high polyembryony, denominated as BHP (brachytic, high polyembryony) and NHP (normal height, high polyembryony) were used. All these genotypes were planted in the Buenavista Agricultural Experimental Station-UAAAN at Saltillo, Coahuila, Mexico. The frequency of PEm was estimated in all genotypes. It was found that the polyembryony occurs at frequencies from 34 to 66% in the D-02, BHP group, and from 13 to 21% in the segregating groups of the G3-0202 and G3-0201. The squash technique was used for both cytogenetic analyses. Different meiotic irregularities in maize chromosomes were detected, such as irregular association of 10% of chromosomes in metaphase 1, and agglomeration of chromatin in 100% of the cells. In addition, pollen viability was estimated by the staining technique with 1% acetocarmine dye, and it was found that the polyembryonic ones have pollen viability of 100%. In meiosis in prophase, I sub-phase diakinesis, ten pairs of bivalents were confirmed, confirming 2n = 20, both in non-PEm and PEm maize, corroborating mating, and balanced segregation, without the presence of univalent or multivalent. In the chromosomal count carried out in cells in mitosis, only in the BHP-200 polyembryonic family was registered two out of twenty triploid plants. This condition of ploidy is atypical in maize, so it is recommended to analyze more plants from this family.

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