Breeding for Resistance to Stenocarpella Ear Rot in Maize

Bioactive metabolites from Stenocarpella maydis, a stalk and ear rot pathogen of maize

“…Furthermore, as maize seeds mature they accumulate abundant amounts of two class IV chitinases, Chit A and Chit B which have been shown to inhibit the growth of fungi on agar plates and may contribute to resistance to ear rot caused by S. maydis (Huynh et al 1992;Naumann & Wicklow 2010). Late-infected ears may appear sound until the ears are shelled and evidence of 'hidden diplodia' is found with symptoms of seed infection, 'darkened germs' associated with a loss in seed viability being restricted to the tip-end (Rossouw et al 2009). …”

“…B. Sutton (Basionym: Diplodia maydis). Maize diseases caused by Stenocarpella are world-wide in their distribution and Stenocarpella is recognized as the most important ear rot pathogen in nearly all countries where maize is produced (Rossouw et al 2009). While S. maydis is reported from humid zones wherever corn is grown, S. macrospora is most prevalent in humid subtropical and tropical zones where plants exhibiting dry-ear rot and stalk rot may also display symptoms of leaf striping (Latterell & Rossi 1983).…”

Influence of Stenocarpella maydis Infected Corn on the Composition of Corn Kernel and Its Conversion into Ethanol

“…In the United States, Stenocarpella ear rot (formerly Diplodia ear rot) was the most common ear rot disease in the 1950s and 1960s throughout the Corn Belt. Its occurrence greatly diminished during the 1970s and 1980s as a result of breeding for more-resistant hybrids (Rossouw et al 2009). Since then, outbreaks have become more frequent, leading to widespread epidemics in 2000 and 2009, some fields having an incidence of ear infection greater than 50% (Bradley 2009;Rossouw et al 2009).…”

“…Its occurrence greatly diminished during the 1970s and 1980s as a result of breeding for more-resistant hybrids (Rossouw et al 2009). Since then, outbreaks have become more frequent, leading to widespread epidemics in 2000 and 2009, some fields having an incidence of ear infection greater than 50% (Bradley 2009;Rossouw et al 2009). The new resurgence of Stenocarpella ear rot has been attributed to a refocusing of breeding programs on resistances to other maize diseases (Rossouw et al 2009), reduced or no tillage practices (Flett et al 1998), and using less-frequent crop rotations (Flett et al 2001).…”

Evaluation for stable resistance to Stenocarpella maydis in tropical maize (Zea mays L.)

“…However, in maize, underlying issues of epistasis and gene interaction may interfere with expected outcome (ElBadawy, 2012) and there is therefore need for individual off-spring evaluation. In addition, it should be realized that effectiveness of breeding for stable resistance may be influenced by the type of isolates and its interaction with the environment (Rossouw et al, 2009). Previous studies have established multiple inoculations of different ear rot pathogens, as not an appropriate breeding strategy due to antagonistic effects associated with these pathogens (Tembo et al, 2013).…”