Utilization of wild sunflower species for the improvement of cultivated sunflower

Seiler, Gerald J.

doi:10.1016/0378-4290(92)90002-q

Cited by 136 publications

(94 citation statements)

References 68 publications

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“…Concern about the ecological and evolutionary effects of these types of transgenes has been raised repeatedly (e.g., Colwell et al 1985, Tiedje et al 1989, Ellstrand and Hoffman 1990, Raybould and Gray 1993, Rissler and Mellon 1996, Snow and Morán Palma 1997, prompting a closer look at the ease with which crop genes spread to wild populations in various cropwild complexes. Studies of radish, squash, and sunflower, for example, showed that pollinators were capable of transporting crop pollen to related weeds over distances as great as 1 km (Kirkpatrick and Wilson 1988, Klinger et al 1991, 1992, Arias and Rieseberg 1994. Spontaneous hybridization can occur even when Kercher andConner 1996, Stanton 1987 Note: Common color morphs are indicated by XX, and rare morphs are designated by X (frequencies vary among populations).…”

Section: Introductionmentioning

confidence: 99%

Fitness of Hybrids between Weedy and Cultivated Radish: Implications for Weed Evolution

Snow

Uthus

Culley

2001

Ecological Applications

110

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Abstract. Weed species are known to evolve rapidly with their associated crops. A better understanding of the mechanisms and rates of weed evolution could aid in limiting or at least anticipating this process. Spontaneous hybridization between crops and related weed species can transfer crop genes coding for fitness-enhancing traits to wild populations, but little is known about how easily this takes place in various weed-crop complexes. We studied interspecific hybrids between wild and cultivated radishes (Raphanus raphanistrum ϫ R. sativus), which often co-occur and share pollinators. To determine whether the F 1 generation represents a strong barrier to subsequent introgression, we compared the fitness of wild plants and wild-crop hybrids. Two experiments were carried out in Michigan, USA, one with potted plants and the other involving four artificially established populations. In the artificial populations, we used white flower color, a dominant, crop-specific allele, to document the persistence of crop genes over time. Wild plants had yellow flowers, which is a recessive trait. F 1 hybrids had lower fitness than wild plants due to lower pollen fertility, fewer seeds per plant, and delayed flowering. Despite these disadvantages, hybrids contributed substantially to each population's gene pool. After 3 yr, frequencies of whiteflowered plants in the artificial populations ranged from 8% to 22%, demonstrating that crop genes persisted. Other studies of flower color variation in wild populations of R. raphanistrum provide circumstantial evidence for frequent crop-to-wild gene flow. We predict that, if cultivated radish is engineered to possess transgenes coding for traits such as resistance to insect herbivores, disease, herbicides, or environmental stress, these fitnessrelated crop genes will easily spread to R. raphanistrum.

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Section: Introductionmentioning

confidence: 99%

Fitness of Hybrids between Weedy and Cultivated Radish: Implications for Weed Evolution

Snow

Uthus

Culley

2001

Ecological Applications

110

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“…The extensive hybridization with wheat's perennial relatives envisioned herein would bring in a bonus of new resistance genes. The same may occur in sunflower (Seiler, 1992) and other species.…”

Section: B Differences In Selection Criteria Between Perennial and Amentioning

confidence: 90%

Breeding Perennial Grain Crops

Cox

Bender

Picone

et al. 2002

BPTS

159

113

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Abstract:One-third of the planet's arable land has been lost to soil erosion in recent decades, and the pace of this degradation will increase as the limits of our food-production capacity are stretched. The persistent problem of worldwide soil erosion has rekindled interest in perennial grain crops. All of our current grain crops are annuals; therefore, developing an array of new perennial grains -grasses, legumes, and others -will require a long-term commitment. Fortunately, many perennial species can be hybridized with related annual crops, allowing us to incorporate genes of domestication much more quickly than did our ancestors who first selected the genes. Some grain crops -including rye, rice, and sorghum -can be hybridized with close perennial relatives to establish new gene pools. Others, such as wheat, oat, maize, soybean, and sunflower, must be hybridized with more distantly related perennial species and genera. Finally, some perennial species with relatively high grain yields -intermediate wheatgrass, wildrye, lymegrass, eastern gamagrass, Indian ricegrass, Illinois bundleflower, Maximilian sunflower, and probably others -are candidates for direct domestication without interspecific hybridization. To ensure diversity in the field and foster further genetic improvement, breeders will need to develop deep gene pools for each crop. Discussions of breeding strategies for perennial grains have concentrated on allocation of photosynthetic resources between seeds and vegetative structures. But perennials will likely be grown in more diverse agro-ecosystems and require arrays of traits very different from those usually addressed by breeders of annuals. The only way to address concerns about the feasibility of perennial grains is to carry out breeding programs with adequate resources on a sufficient time scale. A massive program for breeding perennial grains could be funded by diversion of a relatively small fraction of the world's agricultural research budget.

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“…Esto es posible, porque se sabe que las plantas espontáneas de girasol están adaptadas a un amplio intervalo de hábitats y poseen considerable variación para la mayoría de las características económicas, agronómicas y de calidad de semilla, para la resistencia a insectos, enfermedades y en general a condiciones ambientales desfavorables (Thompson et al, 1981;Rogers et al, 1982;Seiler, 1988Seiler, , 1992.…”

Section: Introductionunclassified

Análisis meiótico de una cruza entre girasol cultivado (Helianthus annuus L. var. macrocarpus) y girasol silvestre (Helianthus annuus L. ssp. texanus Heiser)

2007

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Patterns of meiotic chromosome pairing were compared between three sunflower plants: cultivated sunflower (Helianthus annuus L. var. macrocarpus, public line HA 89), wild sunflower (Helianthus annuus L. ssp. texanus Heiser, collected in Saltillo, Coah.), and the F 1 hybrid. The study was carried out through analysis of meiocytes in diakinesis and metaphase I, based on the meiotic configuration frequency. Pollen viability was evaluated by means of a staining method. Chromosome pairing was normal in the three materials, with absence of univalents and multivalents, and only chain and ring bivalents were observed, therefore the parental genomes are highly compatible in meiosis. The hybrid showed a chromosome pairing index of 0.82, close to the midparent value (0.80), and the differences between the hybrid and each parental taxon (cultivated 0.87, and wild 0.75) were highly significant. Besides, this index was variable within populations. This indicates that the chiasma number is under multigenic control and is affected by the environment. Thus, a population formed with both progenitors could be used to analyze the quantitative trait loci (QTLs) for meiotic chromosome pairing. The pollen viability in the hybrid (92.58%) was similar to that found in the parental taxa (wild 95.57%, and cultivated 95.33%). The pollen viability of the F 1 was high, it showed fertility, and the parental genomes were highly compatible in meiosis, confirming that there is no barrier for the sexual reproduction, and that gene flow and transference of desirables characters from wild to cultivated H. annuus are easily attainable.

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Utilization of wild sunflower species for the improvement of cultivated sunflower

Cited by 136 publications

References 68 publications

Fitness of Hybrids between Weedy and Cultivated Radish: Implications for Weed Evolution

Fitness of Hybrids between Weedy and Cultivated Radish: Implications for Weed Evolution

Breeding Perennial Grain Crops

Análisis meiótico de una cruza entre girasol cultivado (Helianthus annuus L. var. macrocarpus) y girasol silvestre (Helianthus annuus L. ssp. texanus Heiser)

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