Plant hybrids, interspecific

The genetic differences, if any, between Datura stramonium L. and D. tatula L. have been studied, with particular reference to their alkaloid content. There appears to be no difference between these species either in alkaloid content or in the kinds of alkaloids present in the leaves. Variations in alkaloid content were observed, however, in individual plants of interspecific hybrids, which seems to suggest some genetic differences in the parent species in those factors that affect alkaloid production. This confirms the accepted botanical view that D. stramonium and D. tatula should be regarded as two varieties of a single species. ... 

Schardl CL, Craven KD, Interspecific hybridization in plant-associated fungi and oomycetes A review, MolEcol 12 2861—2873, 2003. 

In plant breeding, obtaining interspecific hybrid is important for introducing desirable genes from wild species to cultivated species. However, it is very difficult to obtain a viable hybrid plant between widely related species. These problems would predominantly come from sexual reproduction such as cross incompatibility, hybrid inviability, etc [118,119]. 

Unilateral incompatibility is a phenomenon in which self-compatible species can be crossed as a female, but not as a male, to self-incompatible species (Abdalla and Hermsen, 1972). Pollen tubes fail to penetrate stylar tissue in self-incompatible (female) X self-compatible (male) crosses. Although most diploid Solarium species are self-incompatible, the Mexican species S. verrucosum is self-compatible. Dinu et al. (2005) found that S. verrucosum could be crossed as a female, but not as a male, to self-incompatible species. It is sometimes possible to find exceptional plants that do not exhibit unilateral incompatibility in self-incompatible X selfcompatible interspecific crosses (Pandey, 1962). The identification of such plants allows a breeder to overcome the unilateral incompatibility crossing barrier. For example, exceptional plants ( acceptors ) that accept S. verrucosum pollen and produce fertile hybrids have been reported (Eijlander et al., 2000). It is interesting that some acceptor plants will accept pollen... 

Jansky, S. H., Rouse, D. 1. (2002). Multiple disease resistance in interspecific hybrids of potato. Plant Disease, 87,266-272. 

We continue our Geisenheim program to breed interspecific varieties besides our broad vinifera-breeding activities and clone selection. . . We are convinced that interspecific hybridization will be fundamental to vine improvement though the German legislation presently will not allow to recommend and plant grape vines which are not vinifera. 

Pugliesi, C., Biasini, M.G., Fambrini, M., and Baroncelli, S., Genetic transformation by Agrobacterium tumefaciens in the interspecific hybrid Helianthus annuus x Helianthus tuberosus, Plant Sci., 93, 105-115, 1993a. 

Pustovoit, G.V. and Kroknin, E.Y., Inheritance of resistance in interspecific hybrids of sunflower to downy mildew, Rev. Plant Pathol., 57, 209, 1978. 

Ronicke, S., Hahn, V., Horn, R., Grone, I., Brahm, L., Schnabel, H., and Friedt, W., Interspecific hybrids of sunflower as a source of Sclerotinia resistance, Plant Breeding, 123, 152-157, 2004. 

Witrzens, B., Scowcroft, W.R., Downes, R.W., and Larkin, P.J., Tissue culture and plant regeneration from sunflower (Helianthus annuus) and interspecific hybrids (H. tuberosus X H. armuus), Plant Cell Tiss. Organ Cult., 13, 61-76, 1988. 

Pugliesi, C., Megale, P., Cecconi, F., and Baroncelli, S., Organogenesis and embryogenesis in Helianthus tuberosus and in interspecific hybrid Helianthus annuus X Helianthus tuberosus, Plant Cell Tissue Organ Cult., 33, 187-193, 1993a. 

A chloroplast location of the gene for Cyt / was suggested by two plastome mutants of Oenothera which were deficient in spectrally detected Cyt/[102], and by the maternal mode of inheritance of Cyt /in interspecific Fj hybrids of Nicotiana [103]. The structural gene (petA) for the Cyt / polypeptide was initially localized and characterized from pea chloroplast DNA [104,105], and subsequently from wheat [106], spinach [107] and Oenothera [108]. Open reading frames of 320 codons have been detected in chloroplast DNA from each of these plants. Comparison with the determined N-terminal sequence of Cyt / indicates the presence of a 35 amino acid residue pre-sequence and a mature polypeptide of 285 amino acid residues. A putative haem-binding site, Cys-Ala-Asn-Cys-His, is located near the... 

P. methystkum could be a sterile (F ) interspecific hybrid of P. wichmannii and P. gibbilimbum, both of which reproduce sexually. However, field observations by these authors suggest that hybrids of the two species do not occur. Their plants are often found growing close to each other without any obvious signs of hybridization. 

Alloplasmlc conversion Is a strategy which emerged from capabilities developed with plant protoplasts. Originally touted as a method for the recovery of exotic Interspecific hybrids (12), protoplast fusion has proven to be an excellent way to approach the wholesale manipulation of mitochondrial genes (13). The predominant trait of note Is cytoplasmic male sterility (cms), which Is of Interest to the seed Industry as a tool to facilitate hybrid seed production. Little or no Impact on possible value-added traits Impacting on food quality, however, Is anticipated from alloplasmlc conversion. 

An efficient protoplast plant system has been developed, based on which interspecific hybrids not available by traditional improvement have been produced by a method of somatic hybridization. 

Interspecific cell hybrids between human and murine cells do not express the rDNA genes of both genes. Interspecific crosses in plants and between Xenopus species have also shown a gene-specific dominance effect. This phenomenon is known as nucleolar dominance and, depending on the chromosomal organization of the hybrid, the rDNA of either one of the species is expressed (Reeder, 1985). These findings indicated that there are some aspects of rDNA transcription that are species specific. The incompatibility between different species has then been... 

Comparative analysis of the PSI subunits among pure line and alloploid species in Nicotiana revealed that an alloploid genome brings about polymorphism of nuclear-encoded subunits (Obokata et al. submitted). This implies that polyploidy and interspecific hybrids have complicated the subunit composition of the photosynthetic apparatus during the plant evolutions. 

Many plants form viable interspecific crosses. Often these are sterile, which results in seedless fruits. Seedless varieties must either be hybrids of seed-producing parents or propagated vegetatively. Sometimes breeders use colchicine to induce polyploidy, resulting in a sexually reproducing interspecific hybrid with a double chromosome complement. 

Most alkaloid genetics research has been performed on interspecific crosses. There are some disadvantages of such studies. While the parent plants are fertile and viable, the hybrid is usually sterile, and the development of most plants is abnormal however, occasional hybrids are viable and vigorous. Seeds are produced in some instances, but the ratio of developed seeds to the number of ovules produced is very low. Also, only a small percentage of the pollen grains is viable. To secure the large number... 

---