Occurrence of partial hybrids in wide crosses between sunflower (Helianthus annuus) and perennial species H. mollis and H. orgyalis

Abstract

Hybridisation between the annual diploid sunflower ( Helianthus annuus)and the perennial diploid species Helianthus mollis and Helianthus orgyalis was obtained by means of a normal crossing procedure or embryo rescue. Hybridisation success was low. All plants examined cytologically appeared to be diploid. However, the phenotypes of these diploids were not intermediate between the parents and, despite great variation, they resembled the female parent-type predominantly. Thirty five percent of plants issued from sunflower pollinated with perennial Helianthus had a phenotype resembling the female sunflower parent. On average, only 5% of the minimum number of expected RAPD and RFLP bands from male parents were recovered in plants produced from mature seeds after pollination of sunflower by H. mollis. More hybrids were found among plants obtained from embryo rescue, with an average of 25% of the male parent bands recovered per plant. Analysis of individual plants indicated the occurrence of various levels of hybridisation. There was a significant positive correlation between the number of phenotype traits related to hybrid status and the number of bands derived from the male parent. A single hybrid plant might possibly represent the product of a 'normal' hybridisation event. The mechanisms behind these unusual events and the consequences for the breeder are discussed.

Genetic and histological characterization of a novel recessive genic male sterile line of Brassica napus derived from a cross with Capsella bursa-pastoris

“…The possible processes involved early elimination of the chromosomes of the male parent, genome rearrangements as a consequence of the genomic shock (McClintock 1984;Madlung and Comai 2004) and diploidization (Faure et al 2002;Liu and Li 2007). Each one of such events could explain the origin of the male sterile hybrid in this study (Fig.…”

“…Partial hybrids with the female parent-type phenotype and chromosome number but some DNA sequences of the male parent have been reported in coffee (Lashermes et al 2000), rapeseed (Cheng et al 2002;Hua et al 2006;Chen et al 2007;Liu and Li 2007;Du et al 2008), rice (Liu et al 1999) and sunflower (Faure et al 2002). The possible processes involved early elimination of the chromosomes of the male parent, genome rearrangements as a consequence of the genomic shock (McClintock 1984;Madlung and Comai 2004) and diploidization (Faure et al 2002;Liu and Li 2007).…”

Ploidy Manipulation and Introgression of Resistance to Alternaria Helianthi from Wild Hexaploid Helianthus Species to Cultivated Sunflower (H. annuus L.) Aided by Anther Culture

“…However, we reported introgression of resistance from a diploid perennial species, H. simulans into sunflower by overcoming the problem of hybrid sterility by resorting to the technique of in vitro colchiploidy (Prabakaran and Sujatha 2004). Interspecific hybrids with other diploid perennials, which are sources of resistance to A. helianthi have been produced but met with partial success while utilizing in resistance breeding programmes (Atlagic et al 1995;Nikolova and Christov 1996;Faure et al 2002).…”

Response of sunflower (Helianthus annuus L) genotypes to PEG-mediated water stress

“…In sunflower, wide hybridization (interspecific and intergeneric) is a useful technique for development of new genotypes with desirable agronomic traits [7][8][9][10][11][12]. For drought tolerance breeding, wild annual species H. argophyllus has been reported to be a potential source for genes for drought resistance and is therefore extensively used by sunflower breeders [13,14].…”

“…For drought tolerance breeding, wild annual species H. argophyllus has been reported to be a potential source for genes for drought resistance and is therefore extensively used by sunflower breeders [13,14]. Wide crosses between cultivated sunflower H. annuus and diploid perennials such as H. mollis (2n=2x=34) are difficult to carry out, and successful hybridization is usually obtained through the use of in vitro embryo rescue methods or appropriate cultivated genotype as mother plant [7,12,15]. It has been established that H. mollis is a potential source of a number of useful traits such as resistance against Sclerotinia sclerotiorum (Lib.)…”