Thanks Greg, will definitely check them out! Great looking squash btw!
greg mosser wrote:
the third season on a landrace like this seems to be the point where the magic really starts happening. not sure why.
To my understanding the magic starts to happen in the third generation because of more genetic diversity really showing up then, and as a result of that, better adapted traits also reveal themselves and can then be further selected by the grower.
I like to think of it like this (the way simplified version and not exactly genetically correct)...
Most varieties today are super inbred so that they will look the exact same year after year, and are therefore generally homozygous (meaning that it has two of the same genes for a specific trait like color or vigor) and will pass these down to the offspring if they are crossed with each other, resulting in no new genetics showing up, which is why they look the same each year.
As a result of this very limited genetic information, it can be very difficult if not impossible for the plants to adapt well to a new area. For example let's say there is the Wongatutna squash (purely fictional, just thought the name sounded cool
). Like many varieties it has been inbred (just bred with others that look like itself) for over 20 years, and as a result has very little genetic diversity available to help it adapt if planted in a new area. It has actually gotten weaker over the years, even when grown in its original area, due to some possible genetic diversity being lost every year that it is further inbred. It was developed in the northern US and does pretty well there, but let's say that we live in the southern US. We see the nice shiny picture in the seed catalog in the Spring, and we order a packet. There is a very good chance that it would struggle in the Southern US because it doesn't have the available genetics to be able to adapt to the different diseases, pests, and climate there. So it cannot thrive without any inputs and dies shortly after sprouting.
With a true landrace there is hopefully a lot more genetic diversity, and there is hopefully some heterozygous (containing different genes for a trait) or at least different homozygous plants, and therefore much better at adapting. Let's say we grew the same squash mentioned above from the north but that it was a landrace. I'm guessing that it would still struggle in the South its first year, but that it may have at least a few plants that do well or even very well, or at least there are beneficial traits that show up in different plants, where those plants could be combined to create a super well adapted landrace for your area.
Let's look at how that could be accomplished.
Using simplified Mendelian genetics with capital letters representing dominant traits, let's say that we have two squash. One has a genotype of DDvv (disease susceptible and vigorous) and another is the opposite ddVV (disease resistant and not vigorous ). The capital D will represent a gene for being disease susceptible and the lower case d will be disease resistant. And similarly V will represent the non vigorous gene and v will be vigorous. Each offspring will get one gene from each parent. The capital letter will represent the dominant gene, and if it has one or two dominant genes the dominant gene is expressed, such as DD or Dd. The lower case letter represents the recessive gene, and for it to be expressed it has to have both be lower case such as dd.
These two plants meet in the garden one day through a mutual bumblebee friend, fall in love, and decide to start a family and make little squash plants.
Their kids get one gene (letter) from each parent and all look like this.
So because the parents are DDvv and ddVV, every single seedling will look the exact same. Whether there are 10 seeds or 100 seeds, they will all be DdVv. They all have one dominant gene for each trait which is expressed, so they all will be disease susceptible and non vigorous.
Why do all my plants look the same? Where is the diversity,? I thought I crossed the plants? Let's give them another year.
Next year the kids have kids which vary and look like this. There are more in number of some (the hybrids) than others, but just for simplicity, here's the different possible kids.
So now in the third year we get all of the options expressed. Based on the genes we finally have some (the last in the list) that show up as both disease resistant and vigorous. We like how some of them taste and save their seeds, and repeat year after year, and eventually our landrace is selected to be generally disease resistant, vigorous, and delicious!
This example isn't exactly accurate since I'm pretty sure vigorousness is usually dominant and some gene expressions aren't simple dominant and recessive, but rather exist on a spectrum. But hopefully it is helpful in describing the "magic" of the third year!