Steve Farmer wrote:Your multicoloured cob is expressing the mixed genes from the parents of the plant the cob grew on, not the pollinator of that cob.
To see the results of the most recent cross pollination you would have to plant the seeds off that cob.
And here's where a little knowledge can be, well, maybe not dangerous but at least inadequate to provide accurate answers.
When I was in uni, we did an experiment growing out different coloured corn seeds and calulating the amount of cross pollination based on the colour ratios of the kernels on the resulting cobs. It does't work for most plants, but in corn the layer of cells responsible for the colour of the kernel is produced by cells of the seed itself, not cells of the maternal plant, so it does indeed express the mixed genes of the parents.
Here's a couple of links -
Breeding for Grain Quality Traits: The challenges of measuring phenotypes and identifying genotypes.
Plant Breeding and Predicting Offspring Traits - kernel color lesson
I'm sure Carol Deppe talked about this in her plant breeding book too.
On a slightly related note, I once attended a lecture by Steve Jones
where he talked a little about his research work on the genetics of stripe patterns on the shells of the local snails. It turned out, if I remember correctly, that the patterns on the shells represented the genetics of the *grandparents* of the snails who carried the shells. Took him ages to figure it out. I still feel a little guilty about that day as it was only a few weeks after my son was born and I turned up at the lecture hall with him in my arms, only to discover that the only available seats were right at the top/back of the hall and the exits were at the front, so I'd have to race down past everyone if he started crying. Steve, who despite being an expert in human genetics had never had any kids of his own, took it all in his stride and every time he came up with lines about stretching our DNA out to the moon, he'd refer to 'our young friend at the back'
and I'd have to hold him up to illustrate. He even came up for a chat later about the latest discoveries about the importance of telomeres, but he got distracted cooing at the baby part way through and I was forced to admit that I hadn't read all the article about it in the latest Scientific American magazine 'cos I kept getting distracted too. It's important to keep genetics practical, not just theoretical!