Induction of Polyploidy in Cucumis melo ‘Chammel’ and Evaluation of Morphological and Cytogenetic Changes

Abstract

This study explored the effects of oryzalin on the polyploidization of a new cultivar, Cucumis melo 'Chammel'. 58 diploid seedlings of 'Chammel' were treated with oryzalin. Their ploidy levels were checked by flow cytometry and number of 5S and 18S rDNA loci were examined by fluorescence in situ hybridization (FISH). Twelve among 58 plants were identified as tetraploids. The tetraploids were self-crossed, and their seeds were harvested. The seeds and seedlings of the tetraploids were compared to the corresponding diploids using morphology and cytogenetic analyses. The seed width, the cotyledon width, and the leaf thickness of the tetraploids increased significantly over those of the diploids. However, the length of the petiole of the tetraploids was shorter than that of the corresponding diploids. The stomata length and width of the guard cells in the tetraploids were longer than in diploids, but the number of stomata per area decreased in the tetraploids. The number of chromosomes was 24 and 48 for the diploids and tetraploids, respectively. Moreover, the chromosomal changes induced by oryzalin were confirmed; the diploids had one pair of 5S rDNA loci and two pairs of 18S rDNA loci, the corresponding numbers were doubled in the tetraploids. These results will help to generate new seedless oriental melon cultivars via polyploidization.

Artificial Polyploidization Enhances Morphological, Physiological, and Biological Characteristics in Melothria scabra Naudin

“…The phenomenon of gigantism caused by polyploidization has been frequently reported in plants from Cucurbitaceae and other families. For instance, in C. lanatus [22,23] and C. melo [18], induced tetraploid plants exhibited significantly larger flowers, leaves, seeds, and fruit size than diploid plants. However, a study by Bae et al [17] was not in line with these findings for tetraploid plants of C. lanatus, and the induced tetraploid plants showed small, thick, and crumpled leaves.…”

“…However, several attempts towards polyploid induction in plants from the Cucurbitaceae family have been made. For instance, in Cucumis melo L., polyploids were successfully induced using oryzalin, where the obtained polyploid plants exhibited substantial morphological changes in seeds, leaves, and stomata compared with the diploid mother plants [18]. A similar study on the same species reported a higher total soluble solid content in tetraploid fruits than in diploid fruits [20].…”

“…However, due to its toxic nature and higher binding affinity to animal cell tubulin protein than to plant tubulin, other antimitotic agents like oryzalin are preferred [13,15]. In recent years, the application of oryzalin has gained popularity for chromosome duplication due to its higher success compared to the predominantly used colchicine, particularly within the Cucurbitaceae family [16][17][18][19]. For example, a previous study reported a comparably high tetraploid induction efficiency (up to 14%) in Cucumis melo var.…”

Phenotypic performance of Srikayang's shallot variety M1 by colchicine induction

“…The mutagen effects of colchicine and EMS are reported to effectively provide morphological variation and alter cell metabolism in Crocus sativus L (Samadi et al 2022). Application of colchicine to Cucumis melo "Chammel" resulted in tetraploid plants whose seeds were wider and heavier than their diploid (Woo et al 2021). Colchicine is also used as a mutagen in gladiolus, petunias, calendula, and chrysanthemums to increase the aesthetic value of such ornamental plants.…”