Resistance to corn leaf aphid (Rhopalosiphum maidis Fitch) in tropical corn (Zea mays L.)

Abstract

Corn leaf aphids (Rhopalosiphum maidis Fitch) are found throughout the year on maize in Hawaii and occasionally cause yield loss. Sweet corn inbred Hi38-71 was observed to have high field resistance to aphids and was chosen for this genetic study. An artificial infestation technique was developed using hair-pin clip cages (2.2 cm diameter) which we devised and built. The cages were applied to field-grown plants into which three wingless viviparous adults were placed. Aphid populations were classified on a 1-10 rating scale after about 2 weeks based on digital images of the cages. Mean aphid coverage ratings were 2.97 for the resistant parent and 7.28 for the susceptible parent (representing [200 insects per cage). The F 1 hybrids showed similar susceptibility (6.72), showing resistance to be recessive in nature. Six generations of the cross between Hi38-71 and susceptible inbred Hi27 were artificially infested to provide a generation mean analysis of 360 treated plants over two growing seasons. A joint scaling test showed that the fit to a 3-parameter additive-dominance model satisfactorily explained the observed variability with no assumed linkage or epistasis. We conclude that resistance to corn leaf aphid in Hi38-71 is conferred by a single recessive gene labeled aph. These results concur with a previous study under uncontrolled natural infestation in a single environment. The hair-pin clip cage method was most effective in distinguishing resistant and susceptible genotypes under diverse natural growing conditions in Hawaii.

Effect of Bt maize on the plant-aphid–parasitoid tritrophic relationships

“…All these results suggest that the differences in aphid abundance obtained are better accounted for by the background of the varieties and the year conditions than by the transgenesis or Event itself. Differences in aphid performance due to maize varietal characteristics have been reported (Carena and Glogoza 2004;So et al 2010) but to fully understand and range the differences observed in the present study a wider baseline information for comparing would be necessary. Transgenic Bt maize did not alter the aphidparasitoid associations and had no effect on the aphid parasitism rates.…”

Genetic inheritance analysis of melon aphid (Aphis gossypii Glover) resistance in cucumber (Cucumis sativus L.)

“…The average number of aphids per plant was used as a basis for identifying aphid resistance in bean (Han et al 1991). There is evidence for genetic control of aphid resistance in many crops, including tomato (Solanum lycopersicum) (Rossi et al 1998), wheat (Triticum aestivum) (Liu et al 2005), barley (Hordeum vulgare) (Mittal et al 2008), melon (C. melo) (Sarria et al 2008;Brotman et al 2002), barrel clover (Medicago truncatula) (Klingler et al 2005), maize (Zea mays) (So et al 2010) and soybean (Glycine max) (Kim et al 2010a, b;Ohnishi et al 2012). However, little is known about the inheritance of aphid resistance in cucumber.…”

Mapping soybean aphid resistance genes in PI 567598B

“…), eight independent dominant genes each confer resistance to the Russian wheat aphid (Diuraphis noxia) from different resistance sources (Liu et al 2005), while one recessive gene contributes to the resistance in Triticum tauschii line SQ24 (Nkongolo et al 1991). A single recessive gene was also found to control resistance to corn leaf aphid (Rhopalosiphum maidis Fitch) (So et al 2010) and the groundnut rosette disease vector, Aphis craccivora, infesting peanut (Herselman et al 2004).…”