Techniques to screen for resistance to insects
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The document discusses techniques for screening crops for resistance to important insect pests in semi-arid tropical regions. It describes standardized techniques used at ICRISAT to screen sorghum, pearl millet, chickpea, pigeonpea, and groundnut for resistance to shoot fly, midge, stem borers, head bugs, pod borers, leaf miners, and tobacco caterpillars. These techniques include infester row, cage, detached leaf, interlard fishmeal, and artificial infestation methods. ICRISAT uses these techniques to evaluate germplasm and breeding lines for resistance to develop cultivars suitable for subsistence farming in semi-arid tropical areas.
Techniques to screen for resistance to insects
- 1. Techniques to Screen for Resistance to Insects Sorghum shoot fly (Atherigona soccata), stem borers (Chilo, Busseola, and Diatraea), midge (Stenodiplosis sorghicola) and head bugs (Calocoris angustatus and Eurystylus oldi) in sorghum; stem borer (Coniesta ignefusalis) and head miner (Heliocheilus albipunctella) in pearl millet; pod borer (Helicoverpa armigera) in chickpea and pigeonpea; and leaf miner (Apraorema modicella) and tobacco caterpillar (Spodoptera litura) in groundnut are the most important pests of cereals and grain legumes in the semi-arid tropics (SAT). Insect pests cause an estimated loss of over US$10 billion annually in the SAT. Since insecticide application is uneconomic under subsistence farming, it is important to develop cultivars with resistance to insects. To achieve these objectives, we have standardized several techniques to screen and select for resistance to insect pests in ICRISAT mandate crops. Infester row technique to screen for resistance to sorghum midge. A B Cage technique to screen for resistance to shoot fly (A), midge (B), and head bugs (C) in sorghum; and no-choice cage (D) techniques to screen for resistance to Helicoverpa and Spodoptera in chickpea, pigeonpea and groundnut. These resistance screening techniques are being used to evaluate germplasm, segregating breeding lines, mapping populations, and transgenic plants for resistance to insect pests world wide. C D Detached leaf assay to screen for resistance to Helicoverpa and Spodoptera in chickpea, pigeonpea, cotton and groundnut. A B Interlard fishmeal technique to screen for resistance to shoot fly. Artificial infestation technique to screen for resistance to stem borer. Use of hot spot locations to screen for resistance to Helicoverpa. ICRISAT is a member of the CGIAR Consortium HC Sharma, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Telangana, India. Email: h.sharma@cgiar.org