107(1)_str10

 

ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 107, No. 1 (2020), p. 71–78
DOI 10.13080/z-a.2020.107.010

Nuclear DNA content and phenotypic traits of the Prunus rootstocks from Poland’s gene resources

Małgorzata PODWYSZYŃSKA, Mirosław SITAREK, Agnieszka MARASEK-CIOŁAKOWSKA, Urszula KOWALSKA

Abstract

The ploidy level can be useful in evaluating reproductive and somatic compatibility, an important parameter in scion and rootstock breeding programs. Evaluation of nuclear DNA content was performed in order to determine ploidy level of 31 rootstocks of genus Prunus for plum, sour cherry and sweet cherry. In the first stage of the research, the conditions of flow cytometry analysis with application of propidium iodide for DNA staining were optimized. Repeatable results and relatively good-quality histograms were obtained using Partec extraction buffer with 1% PVP (polyvinylpyrrolidone) addition, with incubation time from 50 to 90 min. The best internal standard for flow cytometry analysis proved to be tomato (Solanum lycopersicum L.) 2C = 1.96 pg for rootstocks with a nuclear DNA content from 0.55 to 1.64 pg, and soybean (Glycine max (L.) Merr.) 2.50 pg for rootstocks with a larger nuclear DNA contents from 1.8 to 2.3 pg. In five plum rootstocks, 2C values ranged from 0.61 to 0.67 pg indicating their diploid chromosome number. One rootstock was identified as tetraploid (2C = 1.34 pg), and four rootstocks as hexaploids owing to their DNA contents from 2.07 to 2.23 pg. One rootstock was considered a pentaploid due to its 2C value of 1.64 pg which was approximately two and a half times more than in diploid Prunus sp. In nine cherry rootstocks, 2C DNA values ranged from 0.74 to 0.86 pg indicating their diploid chromosome number. Nine cherry rootstocks were identified as triploids with their 2C DNA contents from 1.03 to 1.24 pg. Two cherry rootstocks were considered as tetraploids having 2C DNA of 1.39 pg. The ploidy level of cherry and plum rootstocks was evaluated in relation to morphological and agronomic traits. The tendency to increase the size of stomata and leaves along with an increase in the ploidy level was observed within Prunus rootstock genotypes; however, the correlations between these traits were not so evident. Therefore, stomata and leaf size cannot be considered as a morphological marker indicating ploidy level. The evaluated nuclear DNA contents / ploidy levels as well as stomata and leaf size are the additional descriptors of Prunus rootstocks that can be useful for identifying genotypes.

Key words: flow cytometry, hexaploids, pentaploids, ploidy level, plum, cherry rootstocks, tetraploids, triploids.

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