InsideScience: Asian Origins of Wine Grapes

The advantage of hermaphrodite vines is they fertilise themselves, a gentle breeze will do so, no insects needed.

A female vine needs to be fertilised by another vine, hermaphrodite or male, but it's hit and miss whether pollen reaches the female vine to fertilise it.

Hi Peter,
A hermaphrodite flower is a flower that has both female and male sex organs, whether or not it is capable of self-fertilization is a different issue.

Salute
..

Hi Peter,
A hermaphrodite flower is a flower that has both female and male sex organs, whether or not it is capable of self-fertilization is a different issue.
..

I'm not clear what you are suggesting: if pollen from the male part of a flower on vine A can fertilise the female part of a flower on vine B and vice versa, then why can't the male part of a flower on vine A fertilise the female part of the flower on vine A?

Later Edit: I have long held the belief that vitis vinifera's hermaphroditic flowers allowed for self fertilisation, which I must have learned too many years ago to remember who/where I learned it from. But a brief Google brought this from the USA National Academy of Science

Hermaphroditic (perfect) flowers were a key trait in grapevine domestication, enabling a drastic increase in yields due to the efficiency of self-pollination in the domesticated grapevine (Vitis vinifera L. ssp. vinifera).

source https://pubmed.ncbi.nlm.nih.gov/33837155/

and this from wein.plus

The third possibility are hermaphrodite flowers. Here the male sexual part (seed = pollen) and the female sexual part (stigma) are united in one organ on the plant. This is usually the case with cultivated grapevines. Here the plant is not or hardly dependent on outside help. At the time of flowering, the male pollen sac opens, the pollen is released and collected by the sticky female stigma underneath.

If, during flowering, fertilisation takes place by pollen from the same vine on one (autogamy) or between two flowers (geitonogamy), we speak of self-fertilisation or self-pollination.

source https://glossary.wein.plus/hermaphrodite-flower

https://seedfeed.org/food-category/what ... tion-mean/

As Paul pointed out Picolit is "self-unfruitful"

Salute

Only because Picolit has male flowers which are sterile.

There's 97ha in Italy, 5ha in Slovenia and 'some' in Australia's King Valley according to Wine Grapes. Not a variety much grown, I think the exception proves the point..

I'm not clear what relevance the linked article has.

Reread Paul's post, Picolit flowers are hermaphrodite (both male and female organs). Just think of apple blossoms.

Salute

Picolit has hermaprhoditic flowers, but the pollen is mostly sterile. You need pollen from another variety to fertilize the flowers and cause fruit to set.

-Paul W.

I'm not clear what you are suggesting: if pollen from the male part of a flower on vine A can fertilize the female part of a flower on vine B (assuming both vines have hermaphrodite flowers-If vine A is the same species and variety as vine B it's a type of self- pollination, if vine A is of the same species but different variety its cross-pollination-possible due to one or both vines have an imperfect hermaphrodite flower) and vice versa, then why can't the male part of a flower on vine A fertilize the female part of the flower on vine A (if the male and female organ is on the same flower on vine A -example of a perfect hermaphrodite flower capable of self-fruiting (type of self-pollination)?

Salute

Thousands of wine grape varieties - almost all of them - are self pollinating because they have hermaphrodite flowers and that's the reason they have been cultivated.

Picolit has hermaphrodite flowers and self fertilises where the male flower is not sterile, but because many male flowers are sterile growers plant other varieties nearby to pollinate in order to get more grapes. This default in Picolit may be the reason so little is grown.

then why can't the male part of a flower on vine A fertilize the female part of the flower on vine A (if the male and female organ is on the same flower on vine A -example of a perfect hermaphrodite flower capable of self-fruiting (type of self-pollination)?

It can, and does, with most hermaphroditic varieties. The problem with Picolit is that most of the pollen on the flowers is no good--it's sterile and can't fertilize anything. To get a good set of fruit on the vines, you have to interplant with another variety that produces properly working pollen.

-Paul W.

then why can't the male part of a flower on vine A fertilize the female part of the flower on vine A (if the male and female organ is on the same flower on vine A -example of a perfect hermaphrodite flower capable of self-fruiting (type of self-pollination)?

It can, and does, with most hermaphroditic varieties. The problem with Picolit is that most of the pollen on the flowers is no good--it's sterile and can't fertilize anything. To get a good set of fruit on the vines, you have to interplant with another variety that produces properly working pollen.
-Paul W.

Yup, Paul....like most old vnyds, they were typically planted to a field-blend & interplanted, mostly w/ Verduzzo. When they went to modern viticulture & planted Picolit into its own blocks, that's when the production level of Picolit plunged. Absent a better/more scientific explanation, they attributed that to a malady/disease they termed "floral abortion". But it was later shown, it was just the sterility of the Picolit variety. Least that's the way I understand it.
Tom