Confronting lepidoptera pod-borer problem on chickpea through international collaboration and research

Confronting the Lepidoptera Pod-Borer Problem on Chickpea Through International

Collaboration and Research

Dec 2009

HC Sharma1, J Ridsdill-Smith3, SL Clement2 and G Pampapathy1

For more information, contact: HC Sharma, Principal Scientist (Entomology), e-mail: [email protected]

1International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru 502 324, Andhra Pradesh, India. 2USDA, ARS Plant Germplasm Introduction and Testing Research Unit, Washington State University, Pullman, WA 99164-6402 USA.

3Commonwealth Scientific and Industrial Research Organization (CSIRO), Entomology, Private Bag 5, Wembley 6913, Australia.Funding: U.S. Agency for International Development (U.S.) and Grains Research and Development Corporation (Australia).

IntroductionPod-boring Lepidoptera (Helicoverpa spp.) are serious constraints to chickpea (Cicer arietinum) production in India and Australia, and occasional pests (Spodoptera) of chickpea in the US. In India, the widespread use of insecticides to control H. armigera on cotton, high value vegetables, and grain legumes has led to high levels of resistance to conventional insecticides.

Host plant resistance is an effective management option, but cultivated chickpea has low to moderate levels of resistance to Helicoverpa and Spodoptera. In the absence of good genetic variation for pod-borer resistance in the Cicer primary gene pool, searches for resistance have been expanded to wild relatives (secondary and tertiary gene pools).

Plants and InsectsGermplasm repositories at ICRISAT (India), Australian Centre for Legume Improvement Program at Tamworth, New South Wales, and the USDA-ARS Western Regional Plant Introduction Station, Pullman, Washington (US) provided seed of Cicer accessions.

Perennial species: C. canariense, C. macracanthum,C. microphyllum, C. pungens.

Annual species: C. bijugum, C. cuneatum, C. echinospermum, C. judaicum, C. pinnatifidum, C. reticulatum, C. yamashitae.

Cultivated chickpea: (C. arietinum) genotypes ICC 506 (moderately resistant check), ICCC 37 (susceptible check), and Annigeri (commercial landrace cultivar).

Helicoverpa cultures were maintained at ICRISAT (H. armigera) and CSIRO, Perth, Australia (H. punctigera) laboratories using standard methods. Larvae for screenings in Pullman, Washington will be reared from eggs of Spodoptera exigua purchased from a commercial supplier.

Resistant Screening MethodsDetached leaf assay:

Branches from potted plants embedded in agar-agar medium in plastic cups and infested with larvae (Fig. 1).

Caged larvae on potted glasshouse plants (Fig. 2)

Exposure of field plants to natural infestations.

Data were recorded on leaf damage, larval survival and larval weights.

ResultsTo date, we have screened over 150 accessions of wild Cicer for resistance to H. armigera, and high levels of resistance identified in the accessions of perennial (Table 1) and annual species (Fig. 3). Also, resistance to Australian native budworm H. punctigera exists in some, but not all wild Cicer accessions.

Table 1. Evaluation of perennial wild Cicer for resistance toH. armigera.

Accession Species

Resistance index (RI)1

(Detached leaf assay)

Damage rating2

(Open field trial) Status

ICC 17138 C. pungens 1.71 3.0 ResistantICC 17202 C. canariense 0.73 1.0 Highly resistantICC 17230 C. microphyllum 1.04 4.0 ResistantICC 17238 C. microphyllum 0.71 2.0 Highly resistantICC 17243 C. microphyllum 0.52 1.5 Highly resistantICC 17244 C. microphyllum 0.30 1.0 Highly resistantICC 17247 C. microphyllum 0.29 1.0 Highly resistantICC 17248 C. microphyllum 0.09 2.0 Highly resistantICC 17249 C. microphyllum 0.18 2.0 Highly resistantAnnigeri C. arietinum 2.63 8.5 Landrace lineICC 506 C. arietinum 3.75 9.0 Desi cultivar3

ICCC 37 C. arietinum 3.40 9.0 Susceptible check

1 RI = leaf damage rating x larval weight / (100-percentage survival).2 Damage rating (1=<10% leaf area damaged; 9=>80% leaf area damaged).3 Resistant.

High levels of Helicoverpa resistance have also been detected in wild annual C. reticulatum, which is noteworthy because hybridizations of cultivated chickpea with this wild species are readily obtained and the progenies are fertile. Thus, it should be possible to endow cultivated chickpea with pod-borer resistance genes from wild Cicer.

Cicer reticulatum

Cicer echinospurmum

Cicer bijugum

Cicer arietinum

Kabuli chickpea cv. Sierra

C. pinnatifidum Collecting Cicer microphyllum in India, and inspecting and conducting insect bioassay in Pullman, USA. Cicer cuneatum Fig. 2. No-choice cage technique.

Fig. 1. Detached leaf assay.

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Helicoverpa on cultivated chickpea

Spodoptera on cultivated chickpea

Fig. 3. Weights of Helicoverpa armigera larvae at 10 days after releasing the larvae on leaves of wild relatives of chickpea.