Sunday, 9 March 2008


Here is some useful information to take into consideration when deciding which vegetables to collect seed from. It is not complete and contains no information on Asian vegetables. I will read further and add to the tables when I find useful information.

Vegetables may be grouped into four categories according to their manner of pollination. Home gardeners who want to save seed from vegetable plants can expect group 1 to contain less than 5 percent mixed seed. When seeds are saved from groups 2, 3 and 4, the gardener should use special care to prevent crossing if more than one variety of the same species is grown in the garden.

Group 1. Self-pollinators:
Vegetables with flowers that can receive only their own pollen.
bush, climbing and lima beans
English and Southern peas

Group 2.
Form seed only with pollen from an unrelated plant.

Group 3.
Cross-pollinated vegetables that may set seed from their own pollen (self-pollinated) or from pollen received from another plant (cross-pollinated) and can be divided as follows:
A. Usually pollinated by air-borne pollen:
Swiss chard
B. Usually pollinated by insect-borne pollen:
Brussels sprouts
peppers, hot and sweet

Group 4.
This group has male and female plants. Seeds are formed only when male plants furnish pollen.
some hybrid cucumbers

Pollination may occur between vegetable cultivars, creating new cultivars. For example, plants in the Cucurbitaceae or gourd family belong to four species among which crosses may occur. The success of such crossing depends on the species to which a variety belongs. Plants belonging to the Cucurbitaceae family produce separate male and female blooms on the same plant. Insects are usually required to cross-pollinate blooms.
The following diagram indicates the crosses that can or cannot occur between plants in the genus Cucurbita.

Species joined by a solid line do not cross, but crossing may occur between species connected by a broken line.
The more common varieties of gourd, pumpkin, and squash belong to the species indicated below:
C. pepo: Casserta, Cocozefle, Connecticut Field, Delicata, Early Prolific Straightneck, English Marrow, Golden Custard, Orange Gourd, Pea, Gourd, Small Sugar, Table Queen or Acorn, Tours, Tricolor Spoon Gourd, Uconn, White Bush Scallop, Winter Luxury, Yellow Crookneck, and Zucchini.
C. moschata: Alagold, Butternut, Calhoun, Chirimen, Dickinson Field, Golden Winter Crookneck, Kentucky Field, Large Cheese, Sugar Marvel, and Turkish Honey.
C. mixta: Green Striped Cushaw, Japanese Pie, Silverseed Gourd, Tennessee Sweet Potato, and White Cushaw.
C. maxima: Banana, Boston Marrow, Buttercup, Delicious (all types), Essex Hybrid, French Turban, Hubbard (all types), Mammoth, Mammoth Chili, Marblehead, and Olive.

Pumpkins and squashes do not cross-pollinate with cucumbers, watermelons or citron. Watermelons and citron both belong to the same genus Citullus and, therefore, will cross-pollinate each other. Muskmelons and Casaba melons will cross since they are both in the same genus Cucumis and also in the same species melo.


Patrick said...

I have really a lot of conflicting information with what you say here. I'm looking at a copy of Carol Deppe's Breed Your Own Veg. Varieties, and somewhere that I can't find at the moment is Seed to Seed by S. Ashworth.

Deppe's book clearly says you can grow one each of the 4 squash varieties without risking crossing. I'm pretty sure I saw that in Seed to Seed. I've never seen your diagram before. I don't have enough personal experience offer my own opinion.

Deppe's book says Lima beans will cross, and while my climate is too cold to grow them here I have tried and can say the flowers seemed very open to me suggesting they would cross easily.

As far as I'm aware lettuce is highly inbreeding. My friend Lieven ( breeds lettuces, and he has confirmed this in the past.

There is also a lot of conflicting information with ordinary beans and peas, generally with North Americans reporting crosses as rare and Europeans reporting them as fairly common.

I think parsley is also inbreeding, but I'm not sure about this.

Where did you get the information from this post?

Kate said...

Thanks Patrick. I have now left a request for reliable info on the KGI site and I am sure we will be able to get something better from someone in the forum.

Patrick said...

I guess I didn't say this very well. It wasn't so much that I was trying to say you were wrong, but I was genuinely interested in where you got the information.

Like I said the issue of beans and peas seems to be different depending on where you are. I can believe these things are different for you in Aus. Many of these things are disputed, discussed and people change their minds over time.

If you consider the Latin names for plants, which is related to this topic. If you look at gardening books from a hundred or more years ago, you can see they had totally different ideas for these names and their grouping. Ideas change, and and I was just curious what exactly was behind your post.

Kate said...

Thanks, Patrick and I love people adding to things on this blog. This is one area I am uncertain about and I should have looked into it a bit more. I got the info online from the University of Georgia, as I couldn't find any Australian site (or many sites at all)with info in this form. My father was a nurseryman and was always teaching me complicated plant names. It seemed that as soon as I had got my young tongue around one name it would be changed! So I know how common this is. This has also recently happened with eucalypts - the common Australian gum tree - now there is a second genus (the name of which I have forgotten - where is my father when I need him??)so a gum tree is no longer necessarily a gum tree.Let's see what we can find out, if in fact, anybody really knows!