Publication Review by Tami Schlies

 

The Oregon State University has a very good 23 page publication titled Growing Kiwifruit  (publication PNW 507) which gives step by step details on soil preferences, fertilization, irrigation, trellising options, thinning, harvesting, and storing kiwi.  They use “fuzzy” kiwifruit studies as a basis, but

do include sections on Hardy Kiwi, Kolomikta, and Silver Vine Kiwi as well, and say the vine growth and fruiting habit are the same unless otherwise noted.  I found it to be well written and detailed, with good illustrations.  It is not too technical for those of us who are beginners, but not so vague that it was worthless.  It has separate sections on Establishing Your Kiwifruit Vineyard, Maintaining Your Kiwifruit Vineyard, and Harvest, Handling, and Storage of Kiwifruit so referencing is easy if you have specific questions.

You can get a copy in PDF format for free at their website http://eesc.orst.edu or you can order a hard copy from them for $2.50 at:

 

Publication Orders

Extension & Station Communications

Oregon State University

422 Kerr Administration

Corvallis, OR 97331-2119

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Book Review by Kevin Irvin

 

Tree Fruit PHYSIOLOGY:

Growth & Development

Washington State University Shortcourse Proceedings

 

Published by; Good Fruit Grower

Yakima, Washington

ISBN 0-9630659-6-3

 

I found this book at Amazon.com searching for any book on fruit growing that might be of interest to me. To be honest I wasn’t sure what I was going to get when I ordered it. What I found was an excellent book packed with information, while some of it is technical in nature it is mostly written where anyone can understand it.

 

It’s broken into 4 parts, Part 1: Physiology and Regulation of Tree Fruit Growth and Development, Part 2: Regulation of Vegetative Growth and Development, Part 3: Regulation of Reproductive Growth and Development, Part 4: Regulation of Fruit Quality.

 

What I like about the book most is parts 3 and 4.  part 3 has 4 chapters; Flower Development, Fruit Set, Fruit Development and Fruit Maturity and Ripening.

 

There are 5 terms used to describe pollination requirements: Parthenocarpic; requires no pollination, Self-fruitful; capable of setting a crop following self pollination, Self-unfruitful; requires cross pollination for a crop to set, Triploid; lacking viable pollen, and Incompatible; having viable pollen but incapable of setting fruit when cross pollinated.

 

It was interesting to me to read about the triploid, as we have all heard about this as a variety having another gene than most and that it is usually incompatible at some point in time after grafting ( spits the graft)  now I know it to also be lacking viable pollen!  What I don’t know  is what varieties we grow here in Alaska that are triploids.

 

This book is full of charts and graphs related to the subject matter and in the Fruit Development chapter has a good graphics showing the differences of the three types of fruits; Berry (tomato), Drupe (peach), Pome (apple).

 

Did you ever wonder what determines final fruit size?  There is a good section on this. The most important factor being Genetics! Within cultivars the most important being climate. Seed number comes in third hence pollination. Fruit density is also a crucial factor, as fruit density increases, the ratio of leaves to fruits decreases, resulting in less supply of photosynthate per fruit. Maximum returns therefore are obtained  when the leaf/fruit ratio is optimum. However this optimum can only be established by experience.

 

Of particular interest was What determines fruit shape?  Cultivar plays the most important role in this. But what was interesting was the graphics showing the fruit shape of Delicious apple grown in South Carolina, Michigan and Wenatchee, Washington. This (diagrammatic) of the same apple in three distinctly different parts of the country  showed distinctly different fruit shape!

 

Most of us are familiar with sunscald here in Alaska where our trees are damaged by late winter sun bearing down on the limbs effectively killing limbs or in some cases the whole tree. Did you know there is also a temperature related disorder called ‘delayed sunscald’.  This occurs to the fruit where initial symptoms are minimal and not easily recognized. After storage, the sunscalded areas senesce and turn brown, rendering fruit unsaleable (except for juice!). Red cultivars usually have little or no problem with this disorder.

 

Another interesting thing is on watercore, again most of us are familiar with this and if you grow Chinese Golden Early you are very familiar with it.  Watercore can also be heat induced. In contrast to maturity related watercore (the form we are familiar with), heat-induced watercore occurs as a glassy appearance due to the flooded intercellular spaces caused by heat damage to cell membranes, usually near the surface of the fruit. I don’t think we will ever see heat induced watercore as a problem here in Alaska but it was interesting none the less.

 

The section on tree vigor talks about how vigorous vegetative growth reduces flower bud formation. 1)Hormones, 2) Shading and flower bud quality, and 3) Apical dominance.  Vigorous vegetative growth reduces light penetration into the interior of the tree. At moderate levels of reduced light, spurs become weak, flower bud size is reduced, fruit set is decreased, and fruit quality declines. Under high vigor conditions, it is likely that no flower buds will be formed in the interior, and spurs may actually die.

 

Another interesting topic which most of us have never considered is Root Pruning.  This is an area I have undertaken (as most of you know I grow most of my trees at present in containers) and is something I’ve done out of need to keep roots from becoming pot bound not realizing that studies have been done and that commercial use of root pruning has increased dramatically in recent years.  Affects of root pruning (besides the obvious for container grown trees) include a significant reduction in overall pruning of the branches as well as improved light penetration into the lower canopy. Yield of large fruited cultivars generally has not been influenced, although small fruited cultivars may have reduced yields in some years. Fruit size has generally been reduced, although fruit quality characteristics such as color, firmness, and soluble solids have been increased, and preharvest drop and cork spot reduced by root pruning.

 

This book has been a wealth of information to me and has answered many questions I had on various subjects. It’s very easy to read and understand and I am sure will answer most of your questions regarding fruit set, pollination etc. that we all have wondered and talked about at various times. While some areas are somewhat technical in nature it is easily overcome with the further discussion in the various chapters. There is a good Glossary at the back to explain the different terms. Granted the book talks about mostly varieties we do not grow here in Alaska, but the basics of the book are applied to all cultivars and varieties of the fruits we grow here. I highly recommend this book and if you aren’t connected to the web I am sure your local book store can order this for you. The exact price I paid I don’t remember but it was less than $20.00