Off the Tree, Ready to Eat
Scientists have figured out the genetic basis of seedless fruit
By Carrie Arnold
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Mark Twain called the cherimoya and its cousin the sugar apple “the most delicious fruit known to men.” Though little more than exotic edibles to most Americans, such fruits of the Annona family have been cultivated by people in Central and South America for generations. Even in pre-Columbian times, Annona fruits were enjoyed for their sherbetlike texture and a flavor that resembles a mixture of banana and pineapple. But they also contain numerous hard seeds that make the fruit difficult to eat. And even though seedless fruits such as grapes and watermelons have been cultivated for thousands of years, botanists have not been able to identify exactly why the seeds fail to form.
Then one day a Spanish sugar-apple farmer identified a strange, seedless fruit and brought it to the attention of botanists in Madrid. The scientists consulted Charles Gasser, a molecular biologist at the University of California, Davis, and in a paper published in the Proceedings of the National Academy of Sciences USA, the two labs identified the genetic mutation that enables the plant to produce fruit without seeds. “This study gives us the molecular basis for seedlessness, which is the first time this has been done for a fruit plant,” Gasser says.
With this knowledge, Gasser observes, humans may be able to create other varieties of seedless fruits, such as cherimoyas and tomatoes, that have so far defied conventional breeding techniques. Seeds are crucial to fruit formation because they typically emit hormone signals that bring the fruit into being. Occasionally fruit-bearing plants, such as the banana, will contain a genetic mutation that allows fruit formation without seed development. In others, such as watermelons, a small part of the seed remains intact and sets off the hormone cascade that tells the fruit to develop. Now we have a new piece of the puzzle.
FAQs
How to tell when pears are ready to harvest: When pears are still firm but have the slightest amount of give when squeezed, and when they pass the horizontal tilt test: Hold a pear in your hand, tilt it sideways and give it a little twist. If the pear detaches easily from the tree, it's mature and ready to harvest.
Can you ripen apples off the tree? ›
Unlike some fruits, apples continue to ripen long after they are picked off the tree. This ripening (or over-ripening) affects the texture not the taste of the fruit. (i.e. they won't get sweeter just softer). This ripening is due in large to a harmless, colorless gas that apples emit called ethylene.
When should apples be picked from the tree? ›
Some types of apples are ready to harvest as early as July, while others develop their best flavor during the frosty days of autumn, ripening in October or November. Your window for harvesting apples can extend for several weeks or even months with the right mix of varieties.
How to tell if a pear is ready to eat? ›
Check the Neck for Ripeness daily, by applying gentle pressure to the neck, or stem end, of the pear with your thumb. If it yields to pressure, then it's ripe and ready to eat!
How do you ripen pears after you pick them off the tree? ›
To ripen pears in 4-7 days, store them at room temperature on your counter. If you want to ripen them even faster, put them into a paper bag, fold the top of the bag to close it, and wait 2-4 days for the pears to ripen. Adding ripe bananas or apples to the paper bag will help to ripen the pears in 1-3 days.
Can you eat peaches right off the tree? ›
If the peach is green or even has any hint of green left on it, it needs more time on the tree. A green peach is certainly edible but it's not going to be as sweet and juicy. A peach becomes round as it ripens.
Will peaches ripen after they fall off the tree? ›
Most commercially grown stonefruit are picked before they reach full ripeness because they continue to ripen off the tree. If you find yourself with unripe peaches all you need to do is pop them into a brown paper bag out of direct sunlight at room temperature. Within a day or two they will have ripened.
What month are peaches ready to pick? ›
5. California
The harvest time for all these California peaches begins in late June and runs through mid-September.
What happens if you pick an apple too early? ›
If you bite into an unripe apple, the starch will create a feeling on your tongue that some may describe as dry, sticky, or astringent. Unripe apples may also be quite tart. If you taste an apple like this, it is not a fault of the variety — the apple is meant to be left alone to ripen longer.
Can you eat apples that fall off the tree? ›
Because of the risk of the formation of patulin, it is recommended that dropped apples are not used for fresh eating, juicing, baking or canning.
As for the apples still on the tree, they will serve a purpose. “The fruit will start to decay and eventually drop off the tree around the root zone. And that will decay, and those nutrients will remain in the ground,” Vargas said. Copyright 2024 Nexstar Media Inc.
What happens if you don't pick up apples? ›
However, if you leave the fruit lying on the ground there's a chance the brown rot can spread into the fruit on the tree that is still healthy. You also don't want to leave brown rot spores around your tree where it can start an infection next year.
How long can apples sit after being picked? ›
"If they are kept in cold storage, they can be good for months from the date they are picked. Once you buy them, though, they will last one week out of the refrigerator and six to eight weeks in the refrigerator."
Why do my apples fall off the tree before they are ripe? ›
When there is a heavy fruit load, more apples mean more ethylene and so apples drop early. Environmental stresses such as wind, drought, hot/cold temperatures and summer pruning may contribute to early fruit drop. Other stresses such as nutrient deficiencies, salt toxicity and herbicide drift damage can also be causes.
Will pears ripen if you pick them early? ›
Luckily, pears continue to ripen after they've been picked, so you don't need to feel every fruit in the store in search of the holy grail of pears. Unless you want to eat your pears immediately, the easiest thing to do is to buy them when they're still slightly firm and allow them to ripen at home.
What color are pears when ripe? ›
Once they're picked,they need a little time for their sugars to develop, then they ripen (and sweeten) from the inside out. Some pear varieties change color when ripe. A Bartlett pear acts like a banana—it goes from green to yellow when ready to eat.
Why are my pears falling off the tree before they are ripe? ›
In some cases, fruit drop is nature's way of reducing a heavy fruit load. In other cases, premature fruit drop may be caused by pests and diseases, adverse weather conditions or poor cultural practices.
How do you store pears when they ripen? ›
The ripening process should take seven to ten days. To speed up ripening, place the pears in a tightly sealed paper bag. The fruit gives off ethylene gas, which accumulates in the bag and promotes ripening. For long-term storage, refrigerate unripened pears at a temperature of 32 to 35°F.
