The Use of Crop Wild Relatives in Maize and Sunflower Breeding

Abstract

Conservation of crop wild relatives (CWR) has always been predicated on the promise of new and useful traits, and thus modern genetics and genomics tools must help fulfill the promise and continue to secure the conservation of these resources. However, the vast genetic potential present in CWR is often difficult to tap, as identification of superior alleles can be hampered by the effects of the environment on expression of these alleles and masked in different genetic backgrounds; transfer of superior alleles into breeding pools to create new crop varieties can be slow and expensive. Some crop species have been more amenable to introgression of traits from wild relatives than others. In some cases, these species may be less diverged from their wild ancestors, which become a good source of mono‐ to oligogenic traits, many of which are more qualitative in nature, and sometimes of quantitative traits. Sunflower (Helianthus annuus L.) is an introgression success story, and many traits, including cytoplasmic male sterility, herbicide tolerance, drought and biotic stress resistance, and modified fatty acid profiles, have been introgressed into the cultivated gene pool from wild relatives without depression of oil yield and quality. Others, including maize (Zea mays L.), have shown little progress in widening the cultivated gene pool using exotic sources due to temporary yield depression, potential for loss of quality, and disturbance of current logistical habits. Here, we review the breeding history of sunflower and maize and explore variables that have limited the use of CWR in some species and allowed success in others. Surprisingly, in both sunflower and maize, biological limitations are similar and smaller than expected and appear to be surmountable with sufficient determination. Possible new technologies and policies to allow a deeper mining of these genetic resources in all crop species are discussed.

The Use of Wild Relatives of Safflower to Increase Genetic Diversity for Fatty Acid Composition and Drought Tolerance

“…Recombinant lines with high seed yield and having more water stress tolerance from each interspecific cross are candidate lines for more evaluation in the next generations or for constructing other genetic populations. Gene introgression of many traits such as abiotic and biotic stresses tolerance and disease resistance from wild relatives have been used to expand the gene pool in cultivated species of maize ( Zea mays L.) and sunflower ( Helianthus annuus L.) without any depression of their oil yield and quality (Warburton et al, 2017). In the present study, we used F 3 and F 4 generations in populations.…”

Analysis of the genitor origin of an intergeneric hybrid clone between <i>Zea</i> and <i>Tripsacum</i> for forage production by McGISH

“…2C), respectively. Apparently, (Warburton et al 2017). In addition to the only tetraploid species, Z. perennis (2n = 4x = 40), the others are diploid species (2n = 2x = 20).…”

“…Recently, three new annual diploid species were discovered in Mexico (Sánchez et al 2011). As a valued genetic resource for maize breeding, teosinte has been extensively studied and applied (Warburton et al 2017). The genus Tripsacum, the closest relative to Zea, includes 16 species of warm-season, perennial, bunch-type grasses that are present throughout much of eastern Mesoamerica (Bidlack et al 1999).…”

The emergence of a new weed in maize plantations: characterization and genetic structure using microsatellite markers

“…The high genetic similarity between three C samples from two varieties developed by the same seed breeding company (CR46 and CR50) and one accession of teosinte (Z. mays ssp. parviglumis), could suggest the use of this kind of exotic material in breeding programs, though it does not seem a common practice (Warburton et al 2017). There is a relationship between the C maize varieties and some of the weed under study (those with the highest degree of hybridization).…”