Maximize Fruit Size Part 3

Maximize Fruit Size! Part 3. I’m Greg Martin with today’s Fruit Grower Report.

Peter Hirst from Purdue University has been looking at ways to increase fruit size and they determined that genetics, culture and environment help to control that all the way from the cell size, number and the space in between cells.

HIRST: So if we looked at cell diameter, the interesting thing is most of them end up with cell diameters of about 150 microns or so. So lets look at cell number and here we see something quite different going on. We see a rapid increase of cell number in all our varieties for about 4 weeks or so and then it levels out pretty much.

They did testing on a number of varieties of apples including Golden Delicious, Empire, Gala, Pixie Crunch and they included a crab apple.

HIRST: So in terms of a number of cells in a fruit, there’s a number of things that might effect the number of cells in our fruit. Okay, we all say cell division. Cell division really relates to how fast are those cells dividing and producing new cells.

Hirst says that the various varieties saw different rates of cell division over the same time period early on in the season before tailing off. They found that cell number had a more dramatic effect on fruit size than did the cell size. Then by adjusting temperature they saw something vastly different.

HIRST: Temperature affected fruit size not by having more cells but by having larger cells and if you read the textbook I think it implies that if you have higher temperatures early on, we more cell division and we get larger fruit. Part of that is true, we do get larger fruit but it’s not because of more cell division because cell number was exactly the same, it’s because cell diameter is different.

That’s today’s Fruit Grower Report. I’m Greg Martin on the Northwest Ag Information Network.