Fruit Splitting in Blueberries

The prodigious and regular rainfall we have experienced this Spring may be good for some things, but it is not good for ripening blueberries.  As you can see in the photo below, excess rainfall can cause blueberry fruit to split rendering it unsaleable and inedible.

Split Blueberry Fruit

Split Blueberry Fruit Caused by Excess Rainfall

So, how does this happen?  First off, water splitting happens in other fruits too.  More study has been done on cherries than most other fruits.  Reasons that cherries split are related to cultivar, fruit maturity, temperature of the water that hits the fruit, temperature of the fruit itself, duration of wetness, sugar content, fruit firmness, turgor pressure within the fruit, relative humidity, soil moisture, permeability of the skin and elasticity of the skin.  In blueberries, studies have shown that absorbed water through the skin is one reason, but also via root system uptake (although less so than direct contact).  The incidence of rain-caused splitting is very cultivar dependent and that cultivars with firmer fruit may be more susceptible to splitting.  What, within the fruit itself, could lead to this?  Some studies have suggested that in some cultivars the amount of air-filled spaces between cells could allow more water to enter but not split.  Another stated that cells that weakly adhere to each other may split more readily. A recent study showed that there is a moderately high heritability for fruit splitting, suggesting that this trait can be improved to some degree through plant breeding.

A past survey of MS and LA growers found that fruit splitting could reduce marketable yield by as much as 20% in some cultivars.  This means that cultivar choice is very important to avoid this type of damage.  Results from different studies mostly agree on results of what cultivars split more than others.  Below I have put them into three different categories: ~10% split or less (Low); ~10-19% (Moderate); ~20+% (High).

Low: Alapaha, Austin, Premier, Magnolia, Jubilee

Moderate: Gulf Coast, Chaucer, Columbus, Powderblue, Ochlockonee, Vernon

High: Brightwell (there was discrepancy on this cultivar, but 2 of 3 studies showed it to be high), Climax, Tifblue, Pearl River

One study found that excluding rainfall from the plants (covering them) was not a sure way of eliminating split, although it did reduce it.  Also, fruit on plants that are overhead irrigated appear less likely to split than those on drip irrigation.  New products are now on the market that may help reduce fruit split damage. They have not been tested in Mississippi, but have been tested in Florida and Georgia with encouraging results.

For further information you may refer to the papers below:

D. Marshall et al. 2008. Blueberry splitting tendencies as predicted by fruit firmness. HortScience 43:567-570.

D. Marshall et al. 2007. Laboratory method to estimate rain-induced splitting in cultivated blueberries. HortScience 42:1551-1553.

D. Marshall et al. 2009. Water uptake threshold of rabbiteye blueberries and its influence on fruit splitting. HortScience 44:2035-2037.

D. Marshall et al. 2006. Splitting severity among rabbiteye blueberry cultivars in Mississippi and Louisiana. Intl. J. Fruit Science 6:77-81.

D.S. NeSmith. 2005. Evaluation of fruit cracking in rabbiteye blueberry germplasm. Southern Region Small Fruit Consortium Research Project Progress Report.

M. Dossett and C. Kempler. 2015. Heritability of fruit splitting tendency in blueberry. HortScience (in press) abstract.

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4 responses

  1. Eric, Will this in mind, what blueberries would you recommend for NE MS? Maybe your top 4.

    Jeff Wilson, Ph.D.
    Regional Horticulture Specialist
    NMREC
    P.O. Box 1690
    Verona, MS 38879
    662-566-8019 – office

    • Jeff:
      It depends somewhat on market and management but I like Alapaha for sure. Prince and Vernon are a couple of other early rabbiteye varieties worth looking at. I also think Ochlockonee is good, but it is later harvest. Tifblue is kind of a standard; it splits, but is good for pollination other other cultivars. In North MS you might try some Highbush blueberries too. Duke, Bluecrop, Blueray, etc.

  2. Dr. Stafne,

    I just thought I would give you a little of my 21 years with splitting. Year number 1 my dad and I didn’t know what was going on with the splitting and leaking of our Premiers, and other varieties, but I later found out from Dr. Braswell what happens as you explained.

    I may just have more experience than many of the growers that have been around longer.
    Being here in Harrison County in the Saucier community and a mere 25 miles from the Mississippi Sound, I always seemed to get rain and splitting when other growers were working under normal conditions. I was once shut down for 11 days in 2004 when the rest of the growers were blowing and going. We were actually sweating being able to harvest the balance of the crop because we were being left behind. I’m talking Process not Fresh.

    My main varieties were Premier, Tifblue, and Climax. As you listed Premier are low on the splitting, but I learned as everyone knows, high on the leaking. I have experienced both. My Premiers this year were doing fine as the lead berries were coming on and they were progressing very well until the rain started. They held up well as far as splitting until about day 4 or 5 when the monsoon started. I went up and checked one day and they were not split as you picture shows, the whole bottom was blown out of the bloom end. I don’t recall ever seeing that in the Premiers. It only affected a small portion of the lead berries.

    Then, I checked my Climax after the Premier and naturally they had a more predominant splitting just like your picture. I just went and checked both varieties. I have been out of town a few days and the Premier didn’t have many, if any, split they had fallen off. The Climax still had plenty of split and the Tifblue lead berries seemed to be untouched.

    I have witness through the years the Climax and Tifblue have anything from a cracked skin, split as in your picture and exploded. Exploded, being both Climax and Tifblues turned inside out like popcorn.

    How much rain caused the splitting? One year my Climax split after and unofficial 1/16 inch was caught in my rain guage. I can’t recall how much, if any, rain we had the day before. We must have been having rain because I went up to check them. The 1/16 inch was all in a 24 hour period the best I recall. Then again, I’ve seen ½ in., ¾ in., or an inch plus cause the splitting and then on the other had I’ve seen them not split after receiving those amounts of rain. It seemed as if there was no way to predict it.

    I can tell you this though. The splitting seemed to happen almost immediatey. Maybe, I should have kept some kind of journal, but I didn’t. Many times I had good berries and the rain came in the above mentioned volumes and I would go to the patch as soon as the thunderstorm had passed and it was safe, and the berries were already split. Duration of rain anywhere from 5, 10, 15 minutes and they had exploded in many cases by the time I got to the patch. Sometimes, with no prior rainfall. In other words they weren’t holding any of the prior day’s water from previous rain and get hit again and spilt. They split after no prior rain.

    If one has splitting on the process end of things don’t give up. The 2004 harvest year was my best crop. That was the year we had to lay off 11 days for the splits to drop off. We still managed to miraculously average, processed out in the 30 lb boxes, 8000 pounds per acre. I always wondered what we actually had. 8000/acre in the box + culls + splits + the ones that hit the ground = an incredible crop that year. Just thought I would throw that in.

    Bryan Turan

    • Bryan:
      Thanks for sharing your experience, especially the part about not giving up. Splitting is a somewhat complex issue that involves a cultivar x environment interaction. Splitting can be worse with no prior rain because of rapid uptake of water by the root system coupled with the movement of water directly through the skin. I hope your splits this year aren’t too bad!
      Eric

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