02 June 2015

"Good data never goes stale..."

Such was the advice from my thesis supervisor, regarding record keeping back in the eighties. She was right, and 20 years later I got a published paper after reworking my data on grasstrees (Xanthorrhoea sp) and fire inspired by a technique used to analyse lichen (Rhizocarpon sp) on rockfall debris in New Zealand. Go figure.

So, plant breeding? Wasting water in the shower a few days ago my mind drifted to new vegetable breeding projects. With my purple snow project well advanced, I was musing on possibilities when I recalled some of my suspended projects. In 2011 I crossed Sugarsnap Bush with Purple Podded. After a few intermittent growouts, I got two lines of purple thick podded (snap) tall peas, that unfortunately seemed to have fibre. I was contemplating crossing these back to the original Sugarsnap parent, but that would mean extensive growouts to re-find the three purple genes again so I put the project on hold.

But in the shower I had a lightbulb moment - why not cross the fibrous purple snaps to my now stable low fibre purple snows? The low fibre genes from the purple snows could be carried across to the snaps, the hard to catch dominant purple genes would be present in both parents so would be stable, and the recessive thick pod gene from the snaps wouldn't be too hard to recover. Genius.

I had been compartmentalising the projects - thinking of them as separate projects, when much of the work done in each could complement the other. A quick look through the record book confirmed my thoughts. Luckily I had kept well-labelled bags of all the stages of each breeding program, so finding the correct parents was only a matter of going through the various slightly disorganised plastic tubs in the seed fridges (yes, I now own two dedicated bar fridges for seed storage), and extracted the parents.

Ten seeds each of 4 purple snap siblings, and one selected tall purple snowpea are now soaking on the bench. With luck I will be able to grow these out over winter in the greenhouse, perform some crosses, and get F1 seed for a late spring growout. This would give me F2 seed to recover full purple fiberless snaps in Autumn 2016.

An added bonus is the slight possibility of getting large pods into a sugar snap pea. The gene for thick pod walls is very close on the chromosome to the gene for pod size - the genes are said to be tightly linked. [Edit: I went back to the original paper by Baggett et al, where I first saw mentioned the connection between thick pod walls and short pods. My memory had failed me, it's not linkage, the thick pod wall gene n is actually pleitropic  rather than being linked. That is, the gene doesn't just do one thing, rather it has effects on a number of other traits. Ah, precision...So the following dream might just be that...] Since the original sugarsnap with thick pod walls was on a small podded pea, no one has yet been able to breed a big podded sugarsnap. Although it is a low probability, my cross just might produce a big podded snap. But I'm not holding my breath.