Abstract only

In Kenya, stem borer species, Chilo partellus and Busseolla fusca destroy an estimated 400,000 metric tons, or 13.5%, of farmers' annual maize harvest costing about US$80 millions. Bacillus thuringiensis (Bt) maize controls stem borers without any observable negative effects to humans, livestock and the environment. In 2010, biotech crops occupied approximately 10% or 1.5b ha-1 of total global cropland representing a significant increase from 7% or 140m ha-1. Two public Bt maize (Event 216 and Event 223) lines containing cry1Ab::ubi gene were crossed with two non-Bt maize inbred lines, CML144 and CML159. CKIR6009 and MBR C5 Bc F1-13-3-2-1-B-4-2-B lines were used as resistant checks, while H513 and CML216 were used as susceptible checks. The amounts of Bt ä-endotoxins were quantified in leaf tissues of the parents, F1, and F2:3 successive generations. The study was carried out in a biosafety level II greenhouse. Among the F1 generations the values for mean concentration of Bt ä-endotoxins (ìg/g) for all the crosses under this study were similar to those for the Bt-maize inbred lines as expected. No significant differences for mean concentration of Bt ä-endotoxins were found among F1s for crosses of CML?s and the Bt maize events. However, the F2:3 generations showed a spread of mean concentration for Bt ä-endotoxins from low to high. The observations also imply that where there was a higher mean concentration of the Bt ä-endotoxins, there was also a lower level of plant damage parameters expressed. These results suggest that in the leaf tissues, expression of the concentration of Bt äendotoxins was inherited following the Mendelian segregation

Global Maize Program

English

Lucia Segura

INT2460

CIMMYT Staff Publications Collection