Plum Tree Fertility

So I was trying to see why plum trees have perfect flowers but most are not self fertile.

Dichogamy is when the male part of the flower sheds pollen before the female part is ready to accept it. Is this why the tree is not self fertile? So all of the blooms shed pollen before any of the female parts are open for pollination?

Or perhaps the partially self fertile trees are those where some female parts are ready while some male parts are still shedding pollen?

I ask became all my internet returns simply state it is not self fertile and not why.

I’ve read about avocados of which most varieties have separate male and female flowers on the same tree that open at different parts of the day so another variety with the opposite male-female opening timing is required for good pollination.

Requiring cross-pollination makes evolutionary sense as it would guarantee an infinite amount of genetic diversity.

Just curious. The internet is useful, but sometimes it tends to give those parent to young child answers like ‘because I told you so’ without explanation.

The short answer : in the breeding for specific qualities, fertilization requirements were narrowed.

Meaning most of the plums we talk about growing and are available have already been bred in a way that makes them more likely to be unself fertile?

Many European plum varieties are self fertile, the vast majority of Japanese varieties are self unfertile.

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Plums (and most Prunus species) have what’s called gametophytic self incompatibility. Basically, when a pollen grain lands on a stigma of the same plant, proteins on the stigma cells recognize that the pollen is from the same individual and block growth of the pollen tube, without which the pollen can’t fertilize the flower.



Finally something I can look up.

Makes you wonder why perfect flowers evolved on endosperms if self incompatibility evolved as well to increase biodiversity by forcing cross-pollination.

You’d think we would still have many more male and female trees than we do now.

I may pose this to the Common Descent podcast/YouTube channel folks and see if they will answer.