Interactions between panicle size, insect density, and environment for genotypic resistance in sorghum to head bug, Calocoris angustatus

    Sharma, H C and Lopez, V F (1994) Interactions between panicle size, insect density, and environment for genotypic resistance in sorghum to head bug, Calocoris angustatus. Entomologia Experimentalis et Applicata, 71 (2). pp. 101-109. ISSN 1570-7458

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    Abstract

    Studies were undertaken on interactions between panicle size, insect density, host plant, and the environment for sorghum head bug, Calocoris angustatus Lethiery on five sorghum genotypes in terms of bug population increase, grain damage and loss in grain mass across four panicle sizes (5, 10 or 20 branches/panicle and whole panicle), and three infestation levels (5, 10 and 15 pairs of bugs/panicle). Head bug numbers increased and grain damage decreased with an increase in panicle size in the head bug susceptible cultivars, CSH 1 and CSH 5. However, the increase in bug numbers or decrease in grain damage was not significant in head bug resistant genotypes, IS 17610 and IS 17645. Head bug numbers increased with an increase in infestation level in CSH 1 and CSH 5, however, such an increase was not substantial in IS 17610 and IS 17645. Grain damage was significantly lower in IS 17610 and IS 17645 compared with CSH 1 and CSH 5 across infestation levels. Head bug population increased at a greater rate during the rainy season compared with the dry season. Panicle size and infestation levels accounted for greater variation in grain damage and percentage loss in grain mass during the rainy season than in the dry season. To identify reliable sources of resistance to insects, it is important to study insect host plant-interactions across panicle sizes (levels of food availability), infestation levels and season

    Item Type: Article
    Divisions: UNSPECIFIED
    CRP: UNSPECIFIED
    Uncontrolled Keywords: sorghum;sorghum bicolor;head bug;Calocoris angustatus;Mirid;insect density;plant resistance;food availability;seasonal effects;genotypic effects
    Subjects: Mandate crops > Sorghum
    Depositing User: Mr Charan Sai Ch
    Date Deposited: 22 Oct 2011 09:39
    Last Modified: 22 Oct 2011 09:39
    URI: http://oar.icrisat.org/id/eprint/3094
    Official URL: http://dx.doi.org/10.1111/j.1570-7458.1994.tb01776...
    Projects: UNSPECIFIED
    Funders: UNSPECIFIED
    Acknowledgement: We thank Mr. V. V. Rao and Mr. S. Raja Rao for their assistance in these studies, Drs. K.F. Nwanze and J.M.J deWet for their comments, and Mr. I. Krishna Murthy for typing the manuscript.Approved as Journal Article No. 1293 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancherd, Andhra Pradesh 502 324, India.
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