A nonparametric approach to selection popcorn hybrids to resistance to foliar diseases

Abstract

The northern leaf blight (NLB) (Exserohilum turcicum) and gray leaf spot (GLS) (Cercospora zeae-maydis) are two major foliar diseases affecting maize. Losses caused by these diseases are up to 65%, and genetic resistance is widely employed. In the present study, the genetic resistance levels of popcorn hybrids to NLB and GLS determined with a nonparametric statistical approach using the Kruskal-Wallis and Wilcoxon tests, which also allowed to estimate the genetic advancement values (AdV) for these hybrids. For this, an experi­ment in incomplete randomized block design was carried out in 2007/2008 cropping season and the area under the disease progress curve for NLB and GLS were estimated based on severity. The effect of hybrids was significant (P < 0.10) for resistance to NLB and GLS. All the 42 tested hybrids were resistant to NLB and eight of them were moderately susceptible to GLS. Eight hybrids had outstanding AdV and these materials are able to advance to subsequent stages of the breeding program without restrictions. Additional keywords: Cercospora zeae-maydis; Exserohilum turcicum; selection; Zea mays.