Utilization of wild relatives for maize (Zea mays L.) improvement

Abstract

Experimentally induced introgression and selection during domestication and maize (Zea mays L.) improvement involved selection of specific alleles at genes controlling morphological and agronomic traits, resulting in reduced genetic diversity relative to unselected genes. The plant breeder would have to extend crosses to the wild relatives to introduce novel alleles and diversify the genetic base of elite breeding materials. The use of maize wild relatives (Teosintes and Tripsacum) genes to improve maize performance is well established with important examples dating back more than 60 years. In fact, Teosintes and Tripsacum are known to possess genes conferring tolerance to several biotic and abiotic stress including chlorotic dwarf virus, downy mildew, Fusarium, Striga hermonthica, rootworms, drought and flooding. This review provides an overview of the application of these wild relatives and demonstrates their roles on the development of stress tolerant maize plants. It also highlights the use of Teosintes and Tripsacum to improve selected quantitative traits such as yield.

Genetic resources and breeding of maize for Striga resistance: a review

“…Wild relatives of maize and their progenitors are reportedly major sources of Striga resistance. Teosinte ( Zea diploperennis ), and eastern gamagrass ( Tripsacum dactyloides L.) have been used in breeding programs as sources of Striga resistance ( Abdoul-Raouf et al., 2017 ). The inbred line ZD05 selected for its field resistance to S. hermonthica acquired genes from Z. diploperennis ( Amusan et al., 2008 ).…”

Allopolyploidization facilitates gene flow and speciation among corn, Zea perennis and Tripsacum dactyloides

“…Polyploid provides an effective bridge for a controlled induction of alien genes into cultivated crops and the choice of an allopolyploid bridge plant is preferable due to its genome plasticity (Stebbins 1971;Cheng et al 2016), gene redundancy, asexual reproduction (Comai 2005) and allopolyploid's capability to seldom disrupt selfincompatibility barriers (Miller and Venable 2000). Polyploidy and distinct hybridization have already enriched the genetic background of important agricultural crops (Hajjar and Hodgkin 2007), for example wheat (Jiang et al 2017), rice (Shakiba and Eizenga 2014;Ramos et al 2016), maize (Maazou et al 2017), Brassica (Li et al 2014) and tobacco (Hancock and Lewis 2017).…”

“…Eastern gamagrass (Tripsacum dactyloides), also called "ice cream grass", predominantly found at diploid (2n = 2x = 36) and tetraploid (2n = 4x = 72) levels (Farquharson 1955), belongs to the genus Tripsacum, which resides in the tertiary gene pool of maize and owns many interesting genes for maize improvement (Hardin 1994;Maazou et al 2017). It is a warm-season C4 facultative apomictic perennial forage grass having a remarkable ability to withstand various biotic and abiotic stresses (Eubanks 2006).…”