Agronomically Relevant Traits Transferred to Major Crop Plants by Alien Introgressions

Abstract

Extensive selection for increased crop productivity resulted in increased frequency of extreme traits that eroded diversity for a number of plant attributes making the present day crop genotypes vulnerable to changes in environmental conditions, biotic and abiotic stresses. The early domesticates and wild relatives of crop plants are rich sources of diversity and exhibit better performance under harsh climatic conditions as well as under high pathogen loads. The plant breeders have realized the need of broadening the genetic base of cultivated genotypes and have made genuine efforts to explore alien-diversity to breed genotypes for challenging environmental conditions, improved yield and quality. It is evident from these efforts that incorporation of the alien chromatin into the cultivated background is an important tool to improve plant productivity. In this chapter, we deal with available sources of diversity, methods of alien introgression, available breeding material and its implications in characterization of the alien genes, successful examples of alienintrogression and their contribution to the crop improvement.

The Resurgence of Introgression Breeding, as Exemplified in Wheat Improvement

“…In addition, it has been proposed to add a fourth gene pool (GP-4) to acknowledge the potential of transgenesis (Suslow et al, 2002;Kumar and Rustgi, 2014) and somatic hybridization (Xia et al, 2003) to introduce genes without any requirement for the prior formation of a sexual hybrid. While wheat's GP-4 in principle harbors every living organism, from microbe to mammal, it also includes a number of related species, notably sorghum (Sorghum bicolor), Job's tears (Coix lacryma-jobi), and Cogon grass (Imperata cylindrica) (Liu et al, 2014); while it is possible to culture in vitro immature hybrid embryos formed when wheat is pollinated by these species and to regenerate viable plants, the non-wheat chromosomes are rapidly eliminated during the zygote's early cell divisions, so that the regenerants are effectively wheat haploids.…”