Using Fig. 4.1, explain how any two characteristics of this flower make it adapted for wind pollination.
Explain the way in which this resistance could have evolved.
The recessive allele, $r$, in corn borers provides resistance to Bt toxin. Corn borers that are homozygous for the normal, dominant allele $R$, or that are heterozygous, are killed when they feed on Bt maize. State the genotype of the corn borers that successfully change from larvae into adults in the fields where Bt maize is grown.
To cut the number of corn borers resistant to Bt toxin, farmers in the USA must grow up to 50% of their maize as non-Bt varieties. The non-Bt maize is planted in separate areas, called ‘refuges’, near the Bt maize fields. This is known as the HDR strategy. Nearly all corn borer larvae feeding on this non-Bt maize have genotypes $RR$ or $Rr$. The HDR strategy assumes that, when these larvae become adults, they will interbreed with adults developing in the Bt fields. Explain how the HDR strategy could reduce the proportion of corn borers that are resistant to the Bt toxin.
Using the two shaded columns in Table 4.1, explain what the results suggest about how much corn borers from different fields mix together.
Using Table 4.1, suggest and explain what the results of this investigation imply about how effective the HDR strategy will be.