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

Abstract

The current study was set out to establish the efficacy of different mitosis inhibitors (colchicine, amiprophos-methyl, trifluralin and oryzalin) used in the production of red clover (Trifolium pratense L.) and alsike clover (Trifolium hybridum L.) polyploids and to assess the agrobiological traits of tetraploid populations. Four cultivars and five wild populations of T. pratense, one cultivar and three wild populations of T. hybridum were used for polyploidization. The effect of conventional soaking of germinating seeds in a colchicine solution was compared with that of colchicine treatment of embryos in an in vitro culture. Colchicine treatment of T. pratense embryos resulted in 3.3 times higher production of tetraploids (teraploid yield 55.0%) compared with colchicine treatment of seedlings, and the production of chimeric plants was 1.9 times lower. The different mitosis inhibitors were characterised by a diverse polyploidization effect. Tetraploid yield depended not only on the mitosis inhibitor used but also on the plant species. Treatment of T. pratense embryos with colchicine, amiprophosmethyl and oryzalin yielded similar results in terms of tetraploid production (31.3-40.7%) and chimeras (14.3-22.4%). The concentration of trifluralin used for the production of T. pratense tetraploids was ineffective. Colchicine solution was more efficient for the development of T. hybridum tetraploids whose yield was 2.5 times as high as that obtained having treated the embryos with amiprophos-methyl. Induced tetraploid populations were compared to reference cultivars in field trials. The two T. pratense populations 'Radviliai 4n' and 'Arimaičiai 4n' stood out in this respect -their plants accumulated higher dry matter contents, produced more inflorescences than those of the reference cultivar and exhibited prolific seed yield capacity. In relation to the agrobiological traits, the tetraploid populations of T. hybridum did not surpass the reference cultivar.

Scope of Whole Genome Duplication in Forages: A Plant Breeder Perspective

“…In vitro treatment of Trifolium pretense yielded 55.5% higher number of polysomic tetraploids and 1.9 times fewer chimeric individuals when compared with seed imbibition in colchicine solution [25,26]. Colchicine, amiprophosmethyl and oryzalin produced similar frequency of polysomic tetraploid (31-47%) and chimeric plants (14-22%) in T. pratense [25]. Colchicine (0.015% in tissue culture media) was more effective in inducing polysomic tetraploidy (16%) in Trifolium polymorphism species when compared with oryzalin [27].…”

“…A concentration of 5 µm oryzalin was found highly effective over colchicine and trifluralin in inducing chromosome set doubling of calli obtained from interspecific hybrid plants of elephant grass × pearl millet [24]. In vitro treatment of Trifolium pretense yielded 55.5% higher number of polysomic tetraploids and 1.9 times fewer chimeric individuals when compared with seed imbibition in colchicine solution [25,26]. Colchicine, amiprophosmethyl and oryzalin produced similar frequency of polysomic tetraploid (31-47%) and chimeric plants (14-22%) in T. pratense [25].…”

“…Vicia villosa roth and induced polysomic tetraploid plants of the species were dwarf with greater leaf area, stomatal diameter, higher chlorophyll contents, but the polysomic tetraploid delayed and lesser flowering than diploid counterparts [37]. Reconstituted polysomic tetraploid (4×) of Festuca pratensis had 26% dry matter and 100% seed yield advantage over standard check cultivars [25]. For some forage species; i.e., as Dactylis polygama and Lolium perenne, polysomic tetraploids did not differ in biomass yield from diploids but they were superior in terms of forage intake [38] and other forage quality parameters [39].…”

Induced Polyploidy: A Tool for Forage Species Improvement

“…A concentration of 5 µm oryzalin was more effective than colchicine and trifluralin in inducing chromosome doubling of calli obtained from interspecific hybrid plants of elephant grass × pearl millet [24]. In vitro treatment of red clover (Trifolium pratense L.) yielded 55.5% more polysomic tetraploids and 1.9 times fewer chimeric individuals than imbibition of seed in a colchicine solution [25,26]. Colchicine, amiprophosmethyl and oryzalin produced similar frequency of polysomic tetraploid (31-47%) and chimeric plants (14-22%) in T. pratense [25].…”

“…In vitro treatment of red clover (Trifolium pratense L.) yielded 55.5% more polysomic tetraploids and 1.9 times fewer chimeric individuals than imbibition of seed in a colchicine solution [25,26]. Colchicine, amiprophosmethyl and oryzalin produced similar frequency of polysomic tetraploid (31-47%) and chimeric plants (14-22%) in T. pratense [25]. Colchicine (0.015% in tissue culture media) was more effective than oryzalin in inducing polysomic tetraploidy (16%) in peanut clover (Trifolium polymorphum Poir.)…”