Wild Progenitor and Landraces Led Genetic Gain in the Modern-Day Maize (Zea mays L.)

Abstract

Maize (Zea mays ssp. mays) originated from Mexico and Central America and grew worldwide for food, feed and industrial products components. It possesses ten chromosomes with a genome size of 2.3 gigabases. Teosinte (Z. mays ssp. parviglumis) is the probable progenitor of the modern-day maize. The maize domestication favored standing gain of function and regulatory variations acquired the convergent phenotypes. The genomic loci teosinte branched 1 (tb1) and teosinte glume architecture 1 (tga1) played a central role in transforming teosinte to modern-day maize. Under domestication and crop improvement, only 2% (~1200) genes were undergone selection, out of ~60000 genes. Around ~98% of the genes have not experienced selection; there is enormous variation present in the diverse inbred lines that can be potentially utilized to identify QTLs and crop improvement through plant breeding. The genomic resources of wild relatives and landraces harbor the unexplored genes/alleles for biotic/abiotic tolerance, productivity and nutritional quality. The human-made evolution led to the transformation of wild relatives/landraces to the modern-day maize. This chapter summarized the maize’s wild relatives/landraces and the genetic gain over time in biotic/abiotic, productivity, and nutritional quality traits.