Performance of Transgenic Corn Hybrids in Missouri for Insect Control and Yield

Abstract

The efficacy of Bacillus thuringiensis-transformed corn (Zea mays L.) hybrids compared with comparable nontransformed corn hybrids for controlling first- and second-generation European corn borer, Ostrinia nubilalis (Hübner), and second-generation southwestern corn borer, Diatraea grandiosella Dyar, was determined. Yield comparisons were obtained from the same plots of corn hybrids. Both generations of European and the second-generation of southwestern corn borer were effectively controlled, but the Bt hybrids varied in degree of control. Hybrids from Ciba Seeds, DEKALB, and Mycogen had more European corn borer tunneling than those from Novartis or Cargill, and this was generally ascribed to different transgenic events. The Bt-transformed hybrids had virtually no leaf-feeding damage and less tunneling than the non-Bt corn hybrids. Some Bt corn hybrids had no tunneling, whereas other Bt hybrids had a small amount of tunneling. All of the non-Bt hybrids had significant leaf-feeding damage and stalk tunneling from both insects. Only three live European corn borer larvae (stunted) were found in the Bt corn hybrids while splitting stalks to assess tunnel length. When insect damage was significant, and in some evaluations where damage was not significant, differences in yields among hybrids were observed. No significant insect population differences were observed for five genera of beneficial insects for Bt versus non-Bt corn hybrids. Corn hybrids that have been transformed with the Bt gene provide an effective means of control for corn borers and efforts to reduce the likelihood of development of borer resistance are warranted.

Maize–planting date interaction and effect of Bt maize on European corn borer (Ostrinia nubilalis(Hubner) (Coleoptera: Crambidae) damage

“…Similar results were obtained by Barry et al (2000) working with Bt hybrids containing the Cry1Ab crystal protein gene. In our study, where no variation occurred in stalk tunnelling among planting dates as in 2006 at both locations and in 2008 at Hoytville, the yield benefit of using Bt hybrids was insignificant.…”

Response of Last Instar Helicoverpa armígera Larvae to Bt Toxin Ingestion: Changes in the Development and in the CYP6AE14, CYP6B2 and CYP9A12 Gene Expression

“…Spain is the European country with the highest number of hectares sown with Bt maize, 25.3% of the total of 97 346 hectares devoted to the maize crop, and the area has been increasing since Bt maize was introduced in 1998 [1]. The only Bt event sown is MON 810, which expresses the Cry1Ab type protein which is highly effective against the corn borers Ostrinia nubilalis [2] and Sesamia nonagrioides [3]. Maize crops in Spain are attacked by these two corn borers and by other Lepidoptera larvae that are less susceptible to Bt toxin: the leaf feeder Mythimna unipuncta and the maize earworm Helicoverpa armigera [4].…”

Sorghum Molecular Breeding

“…Harlan and de Wet (1972) developed a simplified classification of traditional sorghum cultivars based on spikelet and grain morphology into five basic races, bicolor, caudatum, durra, guinea, and kafir, and ten intermediate races (in all pair-wise combinations of the basic races). In many studies, different marker systems have been used in combination to study the diversity (Tao et al 1993;de Oliveira et al 1996;Smith et al 2000;Agrama and Tuinstra 2003;Uptmoor et al 2003;Geleta et al 2006). With the advent of molecular markers, different DNA marker systems have been employed to study the patterns of genetic diversity among sorghum accessions from the ex situ germplasm collection.…”