Picking on frozen ground

    Rain, snow and endless days of damp cloudy weather has made the 2014 harvest season difficult. When I think back over this year's harvest season, we've had only 8 days of suitable conditions for mechanical harvest.  So when the ground froze hard last night, we greased up the harvester and continued our second harvest (photo above). This year, we are collecting about 150 lbs./acre during our second pass over the orchard floor.
    Picking on frozen ground is a little tricky. Besides pecans, the harvester picks up small clumps of frozen mud. As long as the temperatures stay below 32 degrees F, the mud stays solid and the nuts remain relatively clean. Let those mud balls thaw out and you quickly have a mess of muddy pecans.     To avoid potential mud problems, we run the nuts through our cleaning system as soon as we have collected a hopper full of second-picking nuts. Getting those frozen mud balls out of the sack as soon as possible is critical. Thankfully, the cleaning reel we inserted into our cleaning system removes most of the mud balls before the nuts get to the inspection table.

Posey pecan: early history and current observations

Posey 2014

   During the late 1800's, a large native pecan tree growing on the east bank of the Wabash River became famous for its large nut size and thin shell. History does not record who found the original tree but local residents called the tree, "Grayville",  after the small Illinois town located across the river on the Wabash's west bank. One hundred years ago, esteemed members of the newly minted Northern Nut Growers Association decided "Grayville" was not a very marketable name for a northern pecan cultivar and choose to rename the tree,"Posey", in honor Posey County, IN.  Ironically, the original tree was actually located in Gibson County just north of the Posey county line.  Even though locals continued to call the tree Grayville for much of the early 1900's, the name Posey came into common use as the tree was propagated across the northern pecan region.
    The early 1900's was an exciting time for the naming and propagating of northern pecan cultivars. Names we know today, such as Major, Greenriver, and Posey, were first popularized back in those days. However, other cultivars from that era have largely disappeared from modern pecan orchards including; Busseron, Butterick, Hodge, Indiana, Kentucky, Niblack, and Warrick. It is interesting to me that Posey has survived so long despite some obvious flaws as a pecan cultivar. In 1925, Prof.  A.S. Colby, from the University of Illinois stated, "The Posey is said to be the easiest of the northern cultivars to crack and is of good size. It has the reputation, however, of being a shy bearer."

    I have also noticed that Posey never sets a really heavy pecan crop but I think a more serious cultivar defect is that Posey produces dark colored kernels.  In the photo at left, you can see how dark this year's Posey kernels are as compared to the current season's Kanza kernels. Since dark kernel color is associated with old or rancid pecan kernels, it has become increasingly difficult to market perfectly tasty Posey nut meats to the consumer.

Posey kernels

    In 1923, former NNGA President, T.P. Littlepage, made these observations about Posey. "The parent Posey tree grows in Indiana, and I had the pleasure of naming it. That tree is a good bearer, and it is the thinnest-shelled northern-grown pecan with which I am familiar. It is a very beautiful nut, with the exception that frequently one side of the kernel will not fill out as it does on the other side. It is not defective, but simply deficient."   In the  many years of growing and shelling Posey,  I had never noticed that Posey produces kernel halves of unequal length. However, this year I took the time to carefully remove the shell from several Posey nuts. The photo above shows two examples of what I found. In every case, one half of the Posey kernel was shorter than the other. The difference was sometimes pronounced (nut at left) and at other times only slight (nut at right). Looks like Mr. Littlepage was right.

   

     Posey has a couple of unique characteristics that make field identification of the cultivar easy. Posey nuts are surrounded by a thick, course-textured shuck that features prominent "wings" along the suture lines (photo at left). Posey nuts have dark colored shells and a strongly flattened shape (see photo above).

    The bark of Posey trees is also distinctive.  In the photo at right, you can easily see the graft union between the seedling pecan rootstock and a Posey scion.  The seedling rootstock has furrowed bark typical for pecan trees of this diameter. In sharp contrast, the Posey top exhibits a scaly bark appearance reminiscent of a shagbark hickory.
    Posey is a unique cultivar in many ways. However, it is a cultivar that is fading, slowly being replaced by better northern cultivars.

Native pecan yields for 2014

Native pecan plots 2014

    For 34 harvest seasons, we have been recording the yields of native pecan trees growing in 6, one-half acre plots at the Pecan Experiment Field. We just finished cleaning the last of the nuts from these plots and have weighed this year's crop.
    In the photo at right, the scars from the 2007 ice storm are still visible but you can see how well our native trees have grown back over the past 7 years. This year we harvested an average of 1127 lbs/acre from the native plots, down from the previous year's yield of 1640 lbs/acre (see chart below).
   

 
   Whenever I look at a plot of pecan yields, I always seem to concentrate on finding reasons for why the tree produce below-average yields in certain years. Nut yield in 2007 was depressed by a extremely late hard freeze on Easter weekend that destroyed many emerging shoots and pistillate flowers. Yield in 2008 was impacted by the loss of roughly 50% of tree canopies from a serious ice storm that occurred in December of 2007. In fact, it took several years for the trees to regrow their canopies and get back to full nut production.
    So what happened in 2014? After two big crops in 2012 and 2013, it seems like our trees decided to take a little break. However, I should point out that 2014's yield at 1127 lbs/acre is only slightly below our 34 year average of 1165 lbs/acre.

    When we harvest pecans, we always run over the field twice. In the table above, the 2014 yields for our six native pecan plots are presented in pounds per acre. These numbers give you some idea of how variable native pecan yields can be and how important a second harvest is for capturing the full value of a grove's nut production. In harvesting pecans, we shake and harvest the entire farm before going back for the second harvest.  This year the second harvest represented about 14% of our total yields.

The origins and history of Major pecan

   One of my bad habits is collecting old and rare books about fruit and nut tree growing. The other day, I picked up my copy of the 1912 Yearbook of the Department of Agriculture and discovered a lithograph of new and noteworthy pecan cultivars (photo at right). At the top of the page is an illustration of the Major pecan, a cultivar well known to northern pecan growers. The early history of the Major pecan is described in the text as follows.

   "The parent tree of the Major pecan is located in a native pecan forest near the mouth of the Green river, Henderson County, Ky. It is owned by Mrs. Laurie M. B. Major, of Henderson, in honor of whose late husband it was named. It appears to have attracted considerable local attention previous to 1907, when Mr. C.G. Taylor, of Princeton Ind., sent specimens of the nuts to Mr. W.N. Roper, of Petersburg, Va. The evident merits of the nuts and the account of the tree so favorably impressed Mr. Roper and his partner, Mr. E. Gill Hinton, that the latter went to the original tree during the summer of 1908 for the purpose of obtaining scions, and from the scions then obtained the first nursery-grown trees of the variety were propagated.
    The actual bearing record of this tree has not been kept, but it is stated by persons in the locality of it origin that during recent years it has borne regularly and that frequently the crops have been approximately 100 pounds.  It is a healthy tree 2 1/2 feet in diameter at breast height and 59 feet to the first branch."

Major nuts grown in S.E. Kansas. 2013

    After finding the above report on the Major pecan, I looked to my old copies of the Annual Report of the Northern Nut Growers Association to find additional descriptions of the original Major tree. W.C. Reed, of Vincennes IN, wrote the following in 1915.

     "Major. Crop 1912, 160 pounds saved, and from what information I can get this tree usually bears 100 pounds or more; tree about 3 feet in diameter, 120 feet high and 60 feet to first limb. Owing to its height and size it is very hard to get much an estimate in regard to the crop it may carry until it is gathered. Being located in the dense forest a large part of the crop is often carried off."

    Sadly, the original Major tree was cut down many years ago but the cultivar lives on today and has served as a parent for two important modern-day pecans--Kanza and Lakota.  One of the most vocal proponents of the Major during the mid-1900's was Indiana nurseryman, J. Ford Wilkerson. Mr. Wilkerson was an active member of the Northern Nut Growers Association and attended his first NNGA meeting in 1914. Mr. Wilkerson began cutting scions from old trees including the original Major tree in 1910. To celebrate 50 years of cutting pecan scions, he climbed to the top of a large Major tree that he had planted in 1913. J. Ford Wilkerson was 80 years old when this photo was snapped in 1961 (photo at right). An impressive feat, to say the least.   

One branch sums up the 2014 growing season

     Recently, I cut a single limb from an Osage tree that seemed to sum up the entire 2014 pecan growing season (photo above). First, let me tell you what all those letters in the photo mean.
  
     VS= vegetative shoot
        F= buds frozen by a late spring frost on April 15, 2014
        P= pedicle from the 2013 nut crop
     FS= fruiting shoot

    We harvested a good crop of nuts during the fall of 2013. Judging from the fruiting scars on the pedicle (the portion of the stem that supports a cluster of nuts) this shoot bore three nuts in 2013. When spring rolled around buds started to swell but were frozen by a late spring freeze. The remnants of two buds frozen buds are still firmly attached to the stem. After the freeze, two dormant buds lower on the one-year-old branch broke and started to grow.        
    As these two new shoots grew out in the spring, only one of the shoots produced a pistillate flower cluster. The bud that broke from the lowest portion of the one-year-old stem remained vegetative. This is fairly typical for pecan. The oldest buds (lowest on the stem) on last year's wood have the least potential to produce female flowers.
    When we harvested the 2014 crop, we collected about half as many nuts as we harvested in 2013. Judging from what we can see on this single branch the reasons for lower yields in 2014 become clear.
   

Mohawk: A precautionary tale

   We only have one Mohawk tree left growing at the Pecan Experiment Field (photo at right). Thirty 35 years ago, Mohawk was among the most popular cultivars being grafted in our region and we had dozens of Mohawk trees growing on the farm. At first look, Mohawk had everything a pecan grower would want--large nut size, thin shell, early ripening, and young trees that were both very precocious and productive. The story of Mohawk and the reasons this cultivar has been removed from pecan orchards all across the US is a tale that I always keep in mind as I evaluate new pecan cultivars.     

Mohawk pecans, 2014

    The story begins in 1946 when USDA pecan breeder, Louis Romberg, applied Mahan pollen to a Success pistillate flower. The resulting seed was germinated and grew into a tree that was later named Mohawk in 1965.
     At one time, the Success cultivar was the most popular cultivar grown in the Southeastern US. Success originated as a seedling tree planted in 1875 on a farm near Ocean Springs, MS.  This cultivar produces large thin-shelled nuts but as  the tree matures, nut production becomes erratic and kernel quality suffers terribly during "on" years. As plantings of Success increased across the Southeast, this cultivar became susceptible to pecan scab by 1931.
   Mahan is another cultivar that can trace its origins back to a Mississippi seedling pecan orchard. The tree originated from a seed planted in 1910 near Kosclusko, MS and was named after the nurseryman that first propagated the cultivar. Mahan is known for its very large nut size and long pointed nut shape. However, Mahan is now better known as a cultivar that never fully fills the inside of that large shell with kernel. Mahan is severely alternate bearing and often suffers cold damage following a heavy crop year.

     When Louis Romberg decided to cross Success with Mahan, he was hoping to produce a new pecan cultivar that would exhibit the best qualities of both parents--large nut size, precocious flowering, and heavy nut production. In the photo at right, a single Kanza nut is flanked by two Mohawk nuts. Mohawk is indeed one of the largest pecan cultivars that will ripen before frost in our area. As a young tree, Mohawk produces big beautiful nuts that are well filled and impressive to the consumer. But like both of its parents, serious problems arise when the tree reaches maturity (around 20 years old).    

    Mature Mohawk trees are similar to Success trees in that they frequently set too many nuts on the tree. This leads to poor kernel filling and the development of alternate bearing.  The photo at right illustrates the poor kernel filling of Mohawk as compared to a plump well-filled Kanza nut. Note how much space there is between the shell and kernel of the Mohawk. In addition, the kernel is fuzzy and the tips of the nut meat are shriveled. 
     Mohawk is also similar to Mahan in terms of susceptibility to cold injury. The vast majority of Mohawk trees that once grew on the research station were removed after winter cold killed trees to the ground. This type of extreme cold injury always occurred following a heavy crop year.
     As we grow and evaluate new cultivars, I always keep the story of Mohawk in the back of my mind. What may look like an outstanding new cultivar when a tree is young may turn out to be a real dud when the tree reaches maturity. The history of pecan cultivar development is littered with examples of pecans that fall apart at tree maturity. I'll name a few just off the top of my head: Shoshoni, Chickasaw, Creek, Dooley, Giles, Maramec, and Mohawk.