Inheritance of resistance to head bugs and its interaction with grain molds in Sorghum bicolor. uri icon

abstract

  • Sorghum head bug, Calocoris angustatus, is one of the most important pests of grain sorghum in India. Head bug damage increases the severity of grain moulds, which renders the grain unfit for human consumption. Gene action for resistance to head bugs and grain moulds was studied in a diverse array of male-sterile lines and testers in a line × tester mating design under conditions of natural infestation. Mean squares for parents, parents vs. crosses, lines, testers, and lines × testers were significant for head bug damage and grain mould severity. General combining ability (GCA) effects were significant and negative for ICSA 88019 for head bug damage, and ICSA 88019 and ICSA 88020 for grain moulds (except for ICSA 88020 in 1993). General combining ability effects were positive for ICSA 42 and 296 A. GCA effects of lines and testers for head bug damage and grain mould severity were in the same direction (+ve or -ve). Head bug damage in the grain was significantly correlated with grain mould severity. Testers IS 8891, IS 15107, and TAM 2566 (with coloured grain and less susceptibility to moulds) produced mould-resistant hybrids in combination with all the male-sterile lines, while the reverse was true in the case of Swarna and ICSV 112. Resistance to head bugs showed dominance to partial dominance type of gene action, while in the case of grain moulds, it showed dominance to overdominance. Resistance to these pests is governed by both additive and nonadditive types of gene action. The implications of these results are discussed in relation to needs for crop improvement in sorghum

publication date

  • 2000
  • 2000