Mechanisms and genetic diversity for host plant resistance to spotted stem borer, Chilo partellus in sorghum, Sorghum bicolor uri icon

abstract

  • Levels of resistance to spotted stem borer, Chilo partellus, in the germplasmare low to moderate and therefore we evaluated 25 sorghumgenotypes for resistance to stem borer to identify lines with diversemechanisms of resistance to this insect. Leaf glossiness was significantlyand negatively associated with low deadheart formation. Dwarf genotypeswith fewer nodes showed more deadheart formation. Antixenosisand/or antibiosis for leaf feeding, and reduced deadheart formation, tunnelling,and number of exit holes resulted in lower losses owing toC. partellus damage. Axillary tillers compensated for loss in grain yieldowing to borer infestation as a result of deadheart formation, but theirsynchrony for maturity with the main plant is quite important. Pathcoefficient analysis revealed that direct effects of stem tunnelling on lossin grain yield were greater than leaf feeding and deadhearts. However,leaf feeding via stem tunnelling showed maximum indirect effects onloss in grain yield. Estimates for broad-sense heritability and geneticadvance suggested that it is possible to improve for grain yield understem borer infestation. Heritability estimates for grain yield were usuallyhigher than for stem borer damage parameters. Multi-trait cluster analysisplaced the test genotypes into four and five clusters in rainy andpost-rainy seasons, respectively. The genotypes placed in differentgroups, and showing resistance to leaf feeding, deadheart formation,stem tunnelling, and/or compensation in grain yield can be used for sorghumimprovement

publication date

  • 2012
  • 2012