Hybridization by Grafting: A Long-Standing Debate In a recent issue of Nature , Fuentes et al. (2014) reported that entire nuclear genomes could be transferred across the graft junction to generate a species of allopolyploid plant without sexual
Xiumei Zhou and Yongsheng Liu
Li Jiang, Yun-wen Wang, and Bruce L. Dunn
Lychnis and Silene species have identical somatic chromosome numbers (2n = 2x = 24) ( Negrutiu et al., 2001 ), which suggests the possibility of hybridization for exploring desirable and exotic hybrids for commercial use. Hybridization has been used to
Mariola Plazas, Santiago Vilanova, Pietro Gramazio, Adrián Rodríguez-Burruezo, Ana Fita, Francisco J. Herraiz, Rajakapasha Ranil, Ramya Fonseka, Lahiru Niran, Hemal Fonseka, Brice Kouassi, Abou Kouassi, Auguste Kouassi, and Jaime Prohens
African and Southeast Asian “spiny” species of Solanum ( Vorontsova et al., 2013 ; Weese and Bohs, 2010 ), which yield hybrids with different degrees of fertility when they are hybridized with eggplant ( Daunay and Hazra, 2012 ; Rotino et al., 2014
Joseph Tychonievich and Ryan M. Warner
and other species of Salvia are widely used horticulture crops, the diversity of the genus represents a largely untapped resource for crop improvement, which might be accessed by means of interspecific hybridization. There are a number of known
Mary Lewis, Matthew Chappell, Paul A. Thomas, Rebekah C. Maynard, and Ockert Greyvenstein
successful, naturally occurring interspecific hybridization via pollinator activity ( Wyatt and Broyles, 1994 ). Asclepias is also unusual in that they have two independent ovaries and, if pollinia are inserted perfectly, all subsequent seed will share a
Chunqing Sun, Zhihu Ma, Zhenchao Zhang, Guosheng Sun, and Zhongliang Dai
lilies. To obtain desired traits of interest in cultivars, breeders have tried to make interspecific hybridizations. In the past, interspecific hybridizations in water lily have been performed for the hope of creating a blue hardy water lily hybrid, but
Randall J. Marek and Ronald D. Parker
An interspecific hybridization program involving ancestral species of the Begonia Semperflorens Cultorum Group was initiated to expand the genetic base of this group. Viable seeds were recovered from four reciprocal crosses. F, progenies were sterile and phenotypically intermediate between parental types. Fluorescence microscopy revealed evidence of both sporophytic and gametophytic incompatibility. Post-pollnation responses of flower petals were positively correlated with pollen tube growth in stigmatic, stylar, and ovarian tissue. A digital image analyzer was used to facilitate seed counts and to determine the percentage of ovules that developed into seeds. Seed germination percentages ranged from 0-91 for crosses to 80-99 for selfs.
Patricio A. Brevis, Nahla V. Bassil, James R. Ballington, and James F. Hancock
Ballington, 1986 ). During 100 years of blueberry improvement, homoploid and heteroploid interspecific hybridizations have been used extensively to combine useful traits found in the primary gene pool and to incorporate novel traits from wild germplasm. Wide
Maryke A. Cleland, Cynthia Jones, and Mark H. Brand
An interspecific hybridization program involving five species of Impatiens was initiated to delineate incompatibility barriers. With the exception of one cross, no viable hybrid seed was recovered. Fluorescence microscopy revealed foreign pollen tubes to reach ovules in all crosses, although not all ovules were approached. A histological study involving I. auricoma Baill. and I. walleriana Hook f. ensued to confirm the presence of hybrid embryos. Developing I. walleriana × I. auricoma and reciprocal hybrid embryos were compared to self embryos. Development of hybrid embryos was delayed as early as five days post-pollination. I. walleriana × I. auricoma embryos continued to develop for 8 days post-pollination, but did not reach a size greater than a 5-day self embryo. Excessive endosperm was observed in the hybrid. I. auricoma × I. walleriana embryos continued to enlarge up to ovary abortion but did not reach a size greater than a 7-day self embryo and little to no endosperm developed. Disintegration of ovules included disorganization and collapse of the endosperm, and vacuolization and loss of turgidity of the embryo.
Usha S. Kallemuchikkal and E.B. Peffley
Total genomic DNA was isolated from study plants and was hybridized with 32P-labeled Allium fistulosum `Ishikura' genomic DNA; Southern blots were performed. Plant materials were Allium cepa `New Mexico Yellow Grano', the Allium fistulosum `Heshiko' and `Ishikura', and their F1 interspecific (Allium fistulosum × Allium cepa) hybrids. Sequences with high identity to the labeled DNA hybridized strongly (i.e., A. fistulosum `Ishikura' hybridized most strongly to itself, next with A. fistulosum `Heshiko'). The least hybridization was observed when A. fistulosum `Ishikura' was hybridized with A. cepa `New Mexico Yellow Grano'. Intensity of the signals observed when DNA of the F1 interspecific hybrids was probed with the `Ishikura' DNA was as expected, with the signals intermediate between those of A. fistulosum to A. fistulosum and A. fistulosum to A. cepa. A second study was performed to identify additional cytological markers in Allium. The 5srDNA and NOR genes from Triticum aestivum onto onion chromosomes using in situ hybridization. Evidence of hybridizations are the presence of fluorescing areas on the chromosomes.