Genome constitution of Narcissus variety, ‘Tête-à-Tête’, analysed through GISH and NBS profiling

Abstract

The Narcissus variety, 'Tête-à-Tête', has been the most popular variety since 1949, and a well known allotriploid (2n = 3x = 24 ? B) of spontaneous origin. Because the identity of one of the parents of this variety was uncertain, the genome constitution of 'Tête-à-Tête' was investigated by using genomic in situ hybridization (GISH) and NBS profiling. Both of these techniques confirmed that two different species of Narcissus, viz., N. tazetta (2n = 2x = 20) and N. cyclamineus (2n = 2x = 14) are the parents. GISH clearly identified 10 chromosomes of N. tazetta and 14 chromosomes of N. cyclamineus, the former has contributed one and the latter has contributed two genomes. One B chromosome was identically labelled as those of N. cyclamineus indicating the affinity of the special chromosome to this species. Due to its male and female sterility 'Tête-à-Tête' is unsuitable as a parent for utilizing in further breeding, it might be possible to re-synthesize a 'Tête-à-Tête' like variety using the now known parents and the original pathway.

FISH and GISH reveal genome composition of popular Narcissus cultivars and the possible ways of their origin

“…Similarly in Lilium, GISH can distinguish parental genomes in F 1 , BC 1 and BC 2 when their parental species usually belong to different sections and their F 1 hybrids are highly sterile, then the two parental genomes are different or dissimilar; otherwise, GISH could not discriminate them and the parental genomes are similar or common (Zhou et al 2008;Barba-Gonzalez et al 2006;Lim et al 2003;Van Tuyl et al 2018). These are the reasons why Wu et al (2011) and the present research get same GISH results though the former use N. cyclamineus's DNA as probe while the latter use Dutch Master's DNA as probe. Brandham and Kirton (1987) point out that 'Tête-à-Tête' is from [(N. cyclamineus × N. tazatta 'Soleil d'Or')] × 'Op' (presumably diploid).…”

“…3 and 4). A previous report indicates that 'Tête-à-Tête' contains one set of ten N. tazetta chromosomes and two sets of seven N. cyclamineus chromosomes plus a B -chromosome (Wu et al 2011); while the present GISH indicates that it has a genome of N. tazetta and two genomes of 'Dutch Master'. Seemingly, it contains one genome of N. tazette and two genomes of N. cyclamineus or 'Dutch Master'.…”

“…Brandham and Kirton (1987) point out that 'Tête-à-Tête' is from [(N. cyclamineus × N. tazatta 'Soleil d'Or')] × 'Op' (presumably diploid). Wu et al (2011) suggest that 'Op' is also N. cyclamineus. In our opinion, it is more possible that 'Op' is a diploid variety or cultivar of N. pseudonarcissus.…”

Meiotic restitution mechanisms involved in the formation of 2n pollen in Agave tequilana Weber and Agave angustifolia Haw

“…Harlan and De Wet (1975) suggested that sexual polyploidization is the main mechanism in the origin and evolution of polyploids, so these facts corroborate that the evolution of the genus Agave may have occurred through 2n gametes, just as the existence of several degrees of ploidy. Although there are many known polyploid species so far, the reports about the presence of 2n pollen are much less; in the order Asparagales there are very few reports about the presence of 2n pollen, some examples are Asparagus and Narcissus (Camadro 1994; Wu et al 2011); this is the first report of its kind in the Agavaceae family in which the presence of 2n pollen, its frequencies, as well as the mechanism through which this type of gametes are formed in A. tequilana and A. angustifolia are reported.…”