Persistence of sunflower crop traits and fitness in Helianthus petiolaris populations

GUTIERREZ A; CANTAMUTTO M; POVERENE M

PLANT BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: EH2 3ES Edinburgh, UK; Año: 2011 vol. 13 p. 821 - 830

1435-8603

Transgenic plants have increased the interest on the study of crop gene introgression in wild populations. Genes (or transgenes) conferring adaptive advantages persist in the introgressed populations enhancing competitiveness of wild or weedy plants. This represents an ecological risk that could increase the problem of weed control. Introgression of cultivar alleles into wild plant populations via crop-wild hybridization is primarily governed by their fitness effects. To evaluate this, we studied an experimental hybridizing population of wild Helianthus petiolaris, cultivated sunflower (H. annuus var. macrocarpus) and advanced generation hybrids, trying to mimic the crosses that occur in natural situations. These included two generations of open pollinated progenies of F1 hybrids and backcrosses to the wild parent. We compared a number of morphological, molecular (RAPD), and fitness traits. Multivariate analysis showed that the parental species H. annuus and H. petiolaris differed in a number of morphological traits, while the advanced hybrid generations between them were intermediate. Crop alleles persisted in H. petiolaris populations after hybridization, since specific alleles of sunflower inbred lines were found in the interspecific hybrid progenies. Sunflower crop introgression effectively lowered fitness of hybrid plants. However, fitness parameters tended to recover in the following generations. The fast recovery of fecundity parameters allows predicting that any trait conferring an ecological advantage will diffuse into the wild population even if F1 hybrids have low fitness.