Hybridization Between the Sunflower Species Helianthus annuus and H. petiolaris

Heiser, Charles B.

doi:10.2307/2405326

Cited by 92 publications

(128 citation statements)

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“…Likewise, Doyle and Doyle (1988) found agreement between morphological, pollen stainability and molecular genetic data for Claytonia species and hybrids. In contrast, Rieseberg et al (1988) rejected an earlier conclusion concerning the introgression-mediated origin of a plant race (Heiser, 1949). Data from the genetic analysis of Rieseberg et a!.…”

Section: Introductionmentioning

confidence: 55%

Allozyme variation in Louisiana irises: a test for introgression and hybrid speciation

1990

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Section: Introductionmentioning

confidence: 55%

Allozyme variation in Louisiana irises: a test for introgression and hybrid speciation

1990

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“…The rationale for this explanation lies in the low pollen and seed viabilities observed in F, hybrids between these species, apparently due to meiotic abnormalities (Heiser, 1947;Chandler et aI., 1986). Fertility often is greatly increased in F 2 plants, however, suggesting that it may be possible to overcome the sterility barrier in the F 2 and later generations (Heiser, 1947). Thus, in this scenario it is proposed that an extant population of H. annuus was invaded by an early colonist of H. petiolaris.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, the two species grow together in a variety of locations, and hybrid swarms are common. Pollen viabilities in artificially synthesized F, hybrids range from 0 to 30% and seed set is less than I% (Heiser, 1947;Chandler et aI., 1986). It is also noteworthy that F, hybrids with H. annuus as the maternal parent often are male sterile, possibly due to cytoplasmic male sterility (CMS) (Rieseberg, unpubl.…”

mentioning

confidence: 99%

Chloroplast Dna Introgression in Southern California Sunflowers

1992

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“…This is generally what is found, particularly for species with strong postmating reproductive barriers. Well-characterized examples include Gilia , Helianthus (Heiser, 1947), Layia (Clausen, 1951), Oryza (Li et al, 1997) and Zauschneria (Clausen, 1951). This makes sense, because hybridizing species would merge if the average fitness of the early-generation hybrids was greater than that of the parents.…”

Section: The Fitness Of Different Classes Of Hybridsmentioning

confidence: 99%

“…Thus, after just a few generations of selection, fertile hybrid genotypes can be generated that sometimes outperform both parental species. Second, studies that describe fertility, viability, or other fitness parameters in hybrids almost invariably report the presence of a small fraction of hybrid genotypes that are as fit or fitter than parental individuals, even if the hybrids on average exhibit reduced fitness (Heiser, 1947 ;Valentine, 1947 ;. Third, significant genotype-habitat associations are often reported for hybrid swarms (Stebbins & Daly, 1961 ;Potts & Reid, 1985 ;Cruzan & Arnold, 1993, 1994Arnold, 1997).…”

Section: The Fitness Of Different Classes Of Hybridsmentioning

confidence: 99%

Plant hybridization

1998

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Summary 599 I. Introduction 599 II. Concepts and terminology 600 III. Historical background 600 IV. Studies of experimental hybrids 601 1. Isolating mechanisms 601 2. Prezygotic barriers 602 (a) Gametic barriers to hybridization 602 3. Postzygotic barriers 603 (a) Chromosomal rearrangements 604 (b) Genic sterility or inviability 604 4. Hybrid vigour 605 5. Introgression 606 6. Hybrid speciation 607 V. Experimental manipulations of natural hybrid populations 609 1. Hybrid‐zone formation 610 2. Pollinator‐mediated selection 610 3. Habitat selection 612 VI. The biology of different classes of hybrids 612 1. Character expression 613 (a) Morphological characters 613 (b) Chemical characters 613 (c) Molecular characters 613 2. The fitness of different classes of hybrids 614 (a) The importance of variance 614 (b) Estimating hybrid fitness 615 3. Interactions with parasites and herbivores 616 4. Patterns of mating 617 (a) Outcrossing rate 617 (b) Hybridization frequency 618 (c) Mate choice 618 VII. Conclusions and future research 619 Acknowledgements 620 References 620 Most studies of plant hybridization are concerned with documenting its occurrence in different plant groups. Although these descriptive, historical studies are important, the majority of recent advances in our understanding of the process of hybridization are derived from a growing body of experimental microevolutionary studies. Analyses of artificially synthesized hybrids in the laboratory or glasshouse have demonstrated the importance of gametic selection as a prezygotic isolating barrier; the complex genetic basis of hybrid sterility, inviability and breakdown; and the critical role of fertility selection in hybrid speciation. Experimental manipulations of natural hybrid zones have provided critical information that cannot be obtained in the glasshouse, such as the evolutionary conditions under which hybrid zones are formed and the effects of habitat and pollinator‐mediated selection on hybrid‐zone structure and dynamics. Experimental studies also have contributed to a better understanding of the biology of different classes of hybrids. Analyses of morphological character expression, for example, have revealed transgressive segregation in the majority of later‐generation hybrids. Other studies have documented a high degree of variability in fitness among different hybrid genotypes and the rapid response of such fitness to selection – evidence that hybridization need not be an evolutionary dead end. However, a full accounting of the role of hybridization in adaptive evolution and speciation will probably require the integration of experimental and historical approaches.

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Hybridization Between the Sunflower Species Helianthus annuus and H. petiolaris

Cited by 92 publications

References 0 publications

Allozyme variation in Louisiana irises: a test for introgression and hybrid speciation

Allozyme variation in Louisiana irises: a test for introgression and hybrid speciation

Chloroplast Dna Introgression in Southern California Sunflowers

Plant hybridization

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