Study on gene effects and correlation between morphological traits and common smut (Ustilagemaydis) deasease tolerance in maize (Zea mays L.)

Aim and Background. Since chemical control of corn common smut disease to be unsuccessful (that itsagent is Ustilagomaydis), screening of resistance hybrids to smut disease is necessary for maize breeding. Materials and Methods. In this study, 89 single crosses hybrids including 60 single crosses derived fromhybridization of 20 S6 inbred lines as female parents and 3 S6 commercial elit testers (K18,K19,K1264/5-1) as male parent and 29 new hybrids were evaluated in a RCBD with 2 replications in Agriculture and NaturalResources Center of KhorasanRazavi Province in 2008. The measured traits were leaf no. above ear, totalleaf no., plant height, ear height, anthesis and silking date, anthesissilking-interval(ASI), spore injection time, leaf and stulk disease, ear length, ear diameter, row no./ ear, kernel no./row, physiological maturity, infectedplant percentage, tassel disease percentage, percentage and severity of smut traits, grain hector liter weightand moisture. Results. The ANOVA showed significant differences among test crosses in leaf no. above ear, total leaf no., plant height, ear height, anthesis and silking date, anthesissilking-interval(ASI), spore injection time, stemand leaf disease, ear length, ear diameter, row no./ear, kernel no./row, physiological maturity (p<0.01), andleaf and stem disease (p<0.05). the correlation analysis showed significant positive relations between grainmoisture and smut infection percentage (0.68 **) and diseases severity (0.63**), but we observed negativesignificant relation between grain hectoliter weight with deasease severity (-0.65**) and smut infection percentage (-0.69**). Conclusions. Also, Line×tester analysis for related traits of smut resistance showed significant variance forinfected stem and leaf and infected plant no. that for these traits only additivity gene effect were significant.