Phenotypic identification of near isogenic maize teosinte lines (Zea spp.) involved for resistance to gray leaf spot

Wild germplasm of Zea is a source of variation that could be used in plant breeding to improve maize resistance to diseases such as gray leaf spot (GLS). The objectives were to develop a set of near‐isogenic lines (NILs) carrying introgressions from almost all known wild teosinte taxa in a common maize inbred line background (CML311) and to identify NILs expressing superior resistance to GLS. We developed 2,208 BC3‐derived NILs representing 79 different teosinte populations of 10 taxa as donor parents. We compared the means of NILs grouped by donor to the recurrent and identified donor population El Saucito, (Zea mays ssp. parviglumis race Balsas) as the donor source of NILs with highest mean resistance to GLS. Among the 2,208 NILs, 116 representing diverse introgressions of Zea donors were significantly more resistant than CML311. The most resistant individual line was T1662, derived from San Antonio Tlaltecahuacan donor (Zea mays ssp. mexicana, race Chalco). NILs were characterized for flowering time and yield, and we identified correlations between resistance to GLS and later flowering and lower grain yield.