Trifluralin-mediated polyploidization of Rosa chinensis minima (Sims) Voss seedlings

Abstract

Many diploid rose species and cultivars possess valuable traits that can be introgressed into modern tetraploid cultivars. Interspecific, interploidy crosses are possible, but triploid hybrids typically have limited fertility, hindering further breeding and selection. Tetraploidizing diploids before mating with tetraploids can alleviate fertility barriers. The efficiency of trifluralin was investigated for polyploidization of Rosa chinensis minima (2n = 2x = 14) seedlings. Treatments were trifluralin at 0.086% and 0.0086%, colchicine (0.5%), and distilled water and contained 2% dimethyl sulfoxide and a surfactant. Approximately 5 µl of the treatment solution was applied to the apical meristem of seedlings (N = 337, 82-85 per treatment) in the process of cotyledon expansion. Guard cell length, pollen diameter, and root tip squashes of rooted cuttings were used to detect polyploidy in meristematic layer (L)I, LII, and LIII, respectively. Trifluralin (0.086%) was the most effective treatment for polyploidization (LI 20.2%, LII 12.9%, LIII 12.9%), followed by trifluralin (0.0086%) (LI 10.6%, LII 7.1%, LIII 4.7%) and colchicine (LI 2.4%, LII 0%, LIII 0%). Polyploidization consistently occurred from LI inward. Polyploids as a group had reduced pollen stainability and a lower leaflet length to width ratio than diploids. In addition, two diploid seedlings were identified which produce 2n pollen. Considerations in selecting germplasm and generating somatically-induced polyploids from seedlings versus clones for use in breeding are discussed.

Meiotic aberrations during 2n pollen formation in Begonia

“…Although the existence of 2n gametes has been known for a long time, it was assumed that the production of these gametes was rather sporadic and not useful for plant breeding (Ramanna and Jacobsen, 2003). New methods for synthetic polyploidization of plants through the use of spindle inhibitors, such as colchicine or dinitroanilines (for example, oryzalin and trifluralin), have been developed and successfully used in several plants (Vaughn and Lehnen, 1991;Hancock, 1997;Zlesak et al, 2005;Dhooghe et al, 2009). However, synthetic polyploidization has contributed little to crop improvement, likely owing to fixed heterozygosity (Soltis and Soltis, 2000).…”

Production of Trifolium pratense L. and T. hybridum L. tetraploid populations and assessment of their agrobiological characteristics

“…In the experiment where Rosa spp. apical meristems were treated with trifluralin and colchicine, better results were obtained in the treatment with trifluralin (Zlesak et al, 2005). In another experiment, oryzalin proved to be best suited for polyploidy induction in Rosa (Kermani et al, 2003).…”

Autopolyploids in fodder grass breeding: induction and field performance

“…Some researchers claim trifluralin and oryzalin are less lethal to treated plants than colchicine (Hansen & Andersen, 1996;Cheng et al, 2012). Oryzalin was the most effective antimitotic agent in cork oak double haploid production (Pintos & Manzanera, 2007) and fertility restoration of interspecific currant hybrids (Stanys et al, 2004), trifluralin application was the most efficient in Rosa chinensis minima polyploidization (Zlesak et al, 2005), APM was the best chromosome doubling agent for Allium cepa (Grzebelus & Adamus, 2004). Trifluralin was the least toxic agent for Lolium spp and Festuca pratensis alike in this experiment, yet, at our experiment conditions, it was also the least effective, while oryzalin killed almost all plants.…”