knittlin, as far as I could tell they came true to their parents. I cannot tell with the chickpeas since they have not even flowered yet. I also forgot I did plant the common (pantry) black eye peas a couple of years ago, and that was also very good. It was the first time I had them as shellies and they were delicious, too bad it takes so many of them to make a pound of beans. Lately I try not to plant from the same species close together, but with only 1/4 of an acre I cannot separate my species completely. However, I have many flowering bee attracting herbs (cilantro, mint, marjoram, thyme, oregano, rosemary, sage, lavender, borage), citrus flowers from the lemons, lots and lots of roses, still have tomatoes and eggplant flowering too. I have lots of bees! I put barrier crops all over the place, but with such small space I must have had bees transport DNA from one bean to another....bees have a radius of travel that is over a mile, don't they? I have not noticed any obvious crosses, except at first I was growing three varieties of P. vulgaris pole beans together, and the wax beans sometimes got a little purple tinge probably from the purple pole beans. I am not trading those seeds since I have only barely enough to replant (a bug got in the bean envelope and destroyed/ate a bunch of them, darn!). I am making an effort to only plant different species of pole beans together now. I also figure other gardeners will have similar problems unless they have a huge farm, and getting 1-2 % or so half breeds does not bother me.

I think 50 feet between varieties will give you an almost 100% probability of producing seeds that are true to type. I believe I have read that for commercial seed production the separation distance is even greater. However, for a hobby gardener with a small area available, you will probably produce seeds that are true to type even though the plants are quite close. In my small garden the plants are spaced about 2 feet apart, and the saved seeds are usually true. That said, I did have problems with a couple of varieties in 2012. Last year they did not grow true, and I've gone back to seeds from 2010, which should be fine. Some growers sleeve flowers in fine mesh bags to prevent cross-pollination by insects. Although there is a possibility of wind-borne cross-pollination, it's probably unlikely. What you choose to do will depend on how imperative it is that you get seeds that are true.

As Dave said, the self pollinating and self fertile nature of some plants makes them far less prone to crossing. All perfect flowers are self fertile since they have both male and female parts in the same flower. This increases the likelihood that when it is pollinated, the pollen is transferred only between the same plant, considerably limiting crossing. Not all self fertile flowers are self pollinating though. For example, tomatoes (I'm going to have to disagree with Dave on this) are not a "true" self pollinator.They generally do require outside influence to release the pollen from the anther and deposit it at the stigma. The vibration caused by the buzzing of bumblebees while feeding (there's a name for this that I can't think of right now) is perfect for this type of pollination. So, a bee carrying pollen from a Cherokee purple it just buzzed at could carry some of that pollen to the mortgage lifter planted next to it and cross the two (this is compounded by the fact that literally every tomato cultivar is the same species, Solanum lycopersicum). Of course that is a purely scientific answer and the actual likelihood of this happening in the real world has far more variables involved. I would worry even less about beans as most garden grown snap beans and peas are truly self pollinating. in They will produce a viable seed without outside action due the fact their anthers and stigmas actually touch within the flower (so that when the pollen is shed direct from one to the other). That's not to say that crossing is impossible (otherwise there would be no hybrid beans for sale) just the likelihood of it happening is even less then in a tomato. I'm also going to have disagree with Dave as to the interspecific hybridization among squash. While there is no crossing at the family level (a watermelon can not pollinate a cucumber) and in general no ability cross within the different genre of the Cucurbitaceae family, a few different studies have shown that there is some degree of intergeneric compatibility between some species of domestic Cucurbita. The most prevalent I believe being between C. moschata, C. Pepo, and C. argyrosperma (C. pepo will very easially cross with C. texana and C. fraterna, but both of them are wild types and not generally found in the home garden). C. moschato is actually believed to be a bridge between wild and domestic squashes based on is high level of compatibility with other species. This should not however alarm you. I don't think the compatibility is so great that much more then a small percent of the time will it actually result in a viable crossed seed. In reality, interspecific, and to a slightly lesser extent, intergeneric breeding does happen, both in the wild and in domestic settings. The question is, will differences in phenotype resulting from a cross be apparent to the naked eye? In some cases yes. The alleles will show incomplete dominance and a cross would be apparent at the F1 generation. In other instances though alleles will show complete dominance and the resulting F1 will be identical to the more dominate of the two parents. Such was the case in Gregor Mendel's classic pea experiment. Crossing a purple and white pea flower, all of the resulting F1 pea flowers were purple and white pea flowers did not show back up until the F2 generation. So what does this mean for the home gardener? In some instances we may save seed from an inadvertent cross and the following season we would see the effect of the cross. In others however, the "visual" effects of the cross may not show up until later generations after we saved seed again (I would suspect this to be a much more prevalent problem with crosses in the same species rather then merely the same genus). Say we again pollinate our unsuspected F1 (which looks to us to be identical to a pure butternut squash) with an actual genetically pure butternut. The completely dominate alleles could potentially repress the recessive ones again and we may never know that we in fact are breeding an impure cultivar, at least the genotypic level. The next question is does it matter? If it looks like a butternut, acts like a butternut, and tastes like a butternut, how much should we worry about the genome of our garden plants? So I told you that story to tell you this one: First of all, this is a scientific answer and the reality is that studies done in a lab and growing vegetables in your garden are two totally separate entities. Secondly, I wouldn't be too worried. Most of our garden crops will remain true to type without much help from us. The vast majority of the time, you will be fine. There are a few cases where cross pollination is a real risk (corn and same-species squash right of my head) for the most part your going to be saving true seed. If by chance you have 3 out of 100 seeds that do not grow true, I don't think that is enough to worry about, even when sharing seeds. It may also be important to note that many of these accidental crosses have actually ended up with desirable outcomes. But, If you are still worried about saving 100% genetically pure cultivars of OP crops the preventative measures are not usually difficult, and many plants do not require much, if any. This post was edited by ZachS on Fri, Jan 24, 14 at 17:56

The seeds will be fine, even if treated with pesticides or other chemicals. The only thing that would make the variety come out wrong is if the fruit itself had come from a cross-pollinated flower. But that's very unlikely in most cases.