Caucasian clover (Trifolium ambiguum Bieb.) × white clover (T. repens L.) – interspecific hybrids developed through tissue culture

Abstract

Caucasian clover (Trifolium ambiguumBieb ABSTRACTIn order to create new forage variety, caucasian clover (Trifolium ambiguum Bieb.) with strong tolerance to drought and cold introduced from New Zealand as the female parent was hybridized with a white clover (T. repens L.) collected from northeast China, which has strong nitrogen fixation capacity. Hybrid embryos of caucasian clover×white clover were successfully raised using embryo rescue. 13.8% of these embryos grew to maturity. The successfully grown plants were transferred to sterilized vermiculite after 5-6 weeks and then to field after 3-4 months. The hybrid plant showed intermediate morphological features and a chromosomal number of 2n=5X=40. In order to obtain more plants for backcross, a tissue culture system was established for the hybrids, using MS+0.1mg l -1 2, 4-D+2mg l -1 6-BA, MS +0.5mg l -1 NAA+1mg l -1 6-BA+1mg l -1 KT and 1/2MS as the medium for bud-induction, differentiation and root-induction respectively. 80% of the cultured plantlets survived these growing conditions. Hybridity of the plant was also confirmed by ISSR markers using 16 primers.

A Eurasia-wide polyploid species complex involving 6x Trifolium ambiguum, 2x T. occidentale and 4x T. repens produces interspecific hybrids with significance for clover breeding

“…4 x T. ambiguum fell into the tertiary gene pool (requiring embryo rescue) while 2 x and 6 x T. ambiguum were placed in the quaternary gene pool (requiring both bridge crossing and embryo rescue). Infertile hybrids between 6 x T. ambiguum and T. repens have been reported [23]. If these hybrids subsequently prove to be partially fertile, then 6 x T. ambiguum could be moved to the tertiary gene pool.…”

“…However, direct hybridization would need to overcome potential barriers of geographic distance, diverse ecological adaptations and polyploid speciation. Although F 1 hybrids between white clover and 6x T. ambiguum have been obtained by embryo rescue [23], no fertile F 1 hybrids have so-far been reported, and so the desirable hexaploid form has not been incorporated into the wider gene-pool for clover breeding.…”

A Eurasia-wide polyploid species complex involving 6x Trifolium ambiguum, 2x T. occidentale and 4x T. repens produces interspecific hybrids with significance for clover breeding

“…repens have been reported [23]. If these hybrids subsequently prove to be partially fertile, then 6x T. ambiguum could be moved to the tertiary gene pool.…”

Trabzon-Düzköy İlçesi Yayla Çayırlarının Floristik Yönden İncelenmesi

“…Ak üçgüllerden daha ziyade kuraklığa ve soğuğa karşı güçlü toleransı olan kafkas üçgülü (Trifolium ambiguum Bieb. ), kuzeydoğu Çin'den toplanan ak üçgül (Trifolium repens L.) ile melezlerinden elde edilen yeni türün azot fiksasyon daha yüksek olduğu ortaya koymuştur (Huang et al 2017).…”