Contents - Faperta

Evaluation of Transgenic Plants and Mapping Populations for Resistance to Insect Pests 59
Arnon solution. Place a cotton swab around the stem at the neck of the conical
fl ask to keep the infl orescences in upright condition.
• Place the plants or infl orescences inside a cage (30 30 30 or 50 50 50 cm)
under no-choice, dual-choice, or multi-choice conditions. Known resistant or
susceptible checks should also be placed inside the cage in dual-choice and multichoice
tests. Release 5 to 20 pairs of insects inside the cage for three days, and
repeat the experiment 5 to 10 times.
• Record data on eggs laid after three days. The number of eggs can also be recorded
daily, and the plants changed every day. Compute the oviposition nonpreference
in relation to the number of eggs laid on the resistant or the susceptible check.
Diet Impregnation Assay to Assess Antibiosis
Antibiosis to insects in general is mainly because of poor nutritional quality or secondary
plant substances, for example, gossypol and tannins in cotton (Lukefahr, Martin, and
Meyer, 1965; Sharma and Agarwal, 1983b), tridecanone and tomatine in tomato (Campbell
and Duffey, 1979; W.G. Williams et al., 1980), maysin in maize (Waiss et al., 1979), oxalic
and malic acids in chickpea (Yoshida, Cowgill, and Wightman, 1997), and fl avonoids in
pigeonpea (Stevenson et al., 2005). Antibiosis effects of secondary metabolites can be
measured in terms of survival and development of insects on host plant tissues incorporated
into inert materials or artifi cial diet (Table 3.5). To assess the antibiosis component of
TABLE 3.5
Artifi cial Diet Impregnation Assay to Assess Antibiosis Component of Resistance to Insect Pests
Crop Insect Species Remarks References
Cotton Spodoptera littoralis
(Boisd.)
Pigeonpea Pod borer, Helicoverpa
armigera
Chickpea Pod borer, Helicoverpa
armigera
Maize European corn borer,
Ostrinia nubilalis
Southwestern corn
borer, Diatraea
grandiosella (Dyar)
Sorghum Fall armyworm,
Spodoptera frugiperda
Spotted stem borer,
Chilo partellus
Soybean Corn earworm,
Helicoverpa zea
Gossypol incorporated in artifi cial diet. Meisner et al. (1977)
Ten grams of leaf powder mixed in 250 mL
of artifi cial diet differentiates resistant and
susceptible genotypes.
Ten grams of leaf powder mixed in 250 mL
of artifi cial diet can be used to assess
antibiosis component of resistance.
Bioassays for antibiotic effects should utilize
a diet with limited contaminants,
incorporate tissue on a weight basis,
and focus on silk tissue.
Add 15 g lyophilized husk tissue collected
within 3 days of silk emergence to artifi cial
diet. Weigh the larvae after 21 days.
Greater antibiosis was observed when the
dried milk stage fl orets were mixed with
diet without pinto bean.
Lyophilized leaf powder (10 to 20 g per
250 mL of diet) can be used to assess
antibiosis component of resistance.
Lyophilized pod powder in artifi cial diet can
be used to assess antibiosis component of
resistance.
Kumari, Sharma, and
Jagdishwar Reddy
(2008)
Sharma et al. (2005a)
Warnock et al. (1997)
W.P. Williams and
Buckley (1996)
Diawara, Wiseman, and
Isenhour (1991)
Kishore Kumar, Sharma,
and Dharma Reddy
(2005)
Dougherty (1976)