Introgressing a new source of host-plant resistance to European corn borer into two elite maize inbred lines

Abstract

Eleven accessions of Peruvian maize were evaluated for mechanisms of resistance to leaf feeding by European com borer, Ostnnia nubilalis (Hubner). Antibiosis was identified as one mechanism of resistance that operates at a level equivalent to CI31A which is a maize inbred line containing high levels of 2,4dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), thus having strong antixenotic and antibiotic properties towards leaf feeding by European corn borer. Antixenosis may be another mechanism of resistance operating in the Peruvian maize but at a level lower than CI31 A. The 11 Peaivian maize accessions were used as donor parents in a backcross plant breeding program designed to introgress the European corn borer resistance trait into two elite U. S. Corn Belt adapted inbred lines. Resistance to European corn borer leaf feeding and sheath and collar feeding was recovered in the F1 indicating dominant genetic control. There was no correlation between resistance to European com borer leaf feeding and sheath and collar feeding, indicating that genetic control of resistance to leaf feeding is independent of that for sheath and collar feeding. Some BC2 S1 x Private Tester hybrids of maize had a mean yield not significantly different than the highest yielding commercial check for each experiment. BC3 experimental lines have been developed which have yield potential plus the unique source of resistance to leaf, sheath, and collar feeding by European com borer. Fifteen experimental lines of maize derived from the backcross breeding program were evaluated for resistance to the European com borer, com earworm [Helicoverpa zee vii (Boddie)], fall armyworm, [Spodoptera frugiperda (J. E. Smith)], and sugarcane borer, [Diatraea saccharalis (Fabricius)]. Experimental lines 100-R-3 and 116-B-10 had varying levels of resistance to all of the insects tested. Experimental line 107-8-7 was identified as being resistant to com earworm while maintaining low levels of maysin. Experimental line 81-9-8 had very high levels of resistance to corn earworm. 1 CHAPTER 1. GENERAL INTRODUCTION 13 Abel (1993) and Abel et al. (1995) Identified 11 populations of maize from Peru resistant to leaf feeding by European com borer that was not caused by DIMBOA. Potentially the most valuable property of this maize is that it contains multiple pest resistance. Wilson et al. (1995) identified resistance to western com rootworm, com eaoA^orm, sugarcane borer, and sheath and collar feeding by European com borer in these Peruvian maize accessions. These maize accessions may be useful in integrated pest management systems that manage the primary insects that damage U.S. Com Belt maize. insecticidal Crystal Proteins From Bacillus thuringiensis Bacillus thun'ngiensis (Berliner) (Bt) was formally described from Thuringia, Germany, in 1911 and has been available in commercial formulations for insect control since the 1930's (Beegle and Yamamoto, 1992). Bt was a minor component of pest management until three factors increased its importance; 1) the evolution of resi...