The statement "...cultivars like navel oranges which are inherently more sensitive to stress than most other citrus species" appears in a technical writing. There is no further explanation but another work by the same author is cited. Is this statement supported by the experience of growers? In general, are oranges more sensitive?
Junglekeeper, where did you read the satement: "...cultivars like navel oranges which are inherently more sensitive to stress than most other citrus species" ?
Millet, the quote came from Citrus by Davies and Albrigo. I would give you a page number if I still had the book with me. If you have a copy of it, look in the back in the bibliography under Davies and you'll find two entries. If I recall correctly, reference was made to the first entry dated 1986(?).
"cultivars like navel oranges which are inherently more sensitive to stress than most other citrus species" I would want to know what form of stress were the authors referring to such stress due to heat, cold, insects, diseases, too much fertilizer, too little fertilizer, lack of water, too much water, standing water and where the Navels are grown, as in some cases we cannot compare how a Washington Navel will grow and be affected in Florida in comparison to one of our clonal Navels grown here in the Central Valley. Another important aspect for us to know is which rootstock were the Navels budded or grafted onto which gave rise to more visibly seen sensitivity to stress. There are some forms of Navel Oranges that show some heat and cold stress easier than other Navels will but I would not go that far to say that they are more sensitive than a certain Tangelo will be to cold or a certain Mandarin will be to heat or a certain Grapefruit will be to scale insects. Some of the old clonal forms of Washington Navel were selected out due to them being pretty tough plants grown here in comparison even to some Valencias and Florida Juice Oranges grown here as well. I think to use the term stress and the ramifications thereof to be applied to a variety of Citrus that we need to be explicit, in which context we mean, in relation to which form of stress is being referenced and where and which cultivar or clone of Navel Orange is or are being singled out or grouped together in contrast to other Citrus. To implore that "cultivars" of Navels, across the board, are more sensitive to stress more so than most other forms of Citrus is not always true depending on which Navels they are and where they are grown. Jim
Junglekeeper, I do have the book Citrus in my library, but am unable to find the reference. In my experience the Navel Orange does not seem to be any more sensitive than other citrus to grow. If I ever find the "inherently more sensitive" reference I'll let you know. - Millet
Found it. The quote appears at the bottom of page 71 and the reference (Davies, 1986a) appears on the middle of page 229.
I find out I do not actually have the text that you are refering to. I do have a rather thick, hard bound book titled "Citrus," but the authors are Giovanni Dugo and Angelo Di Giacomo. and the references you refer to are of course not on thoses pages. I also could not find the book that you have, in the Florida Science Source, Inc. catalog. The Florida Science Source, has one of the largest collections of citrus literature available for purchase. I'll have to look on the Internet to see if I can find it. I have alway thought it is bad policy for an author to make statements of "fact" without giving support to back the "facts" up. Personally I find Navel Oranges, to be easier than some other types of citrus, such as Meyer Lemons. I guess I would not agree, with Davies and Albringo without further explanation. I think Jim's thread above hit it on the nose, when his writes, more sensitive in whay way. The original first ever American, Washington Navel mother tree is still alive and well and is growing in California. There is a book titled "Citrus Crop Production Science In Horticulture," by F. Davies and L.G. Albrigo. Is this the book you are refering to? - Millet
Yes - that's the book [ISBN: 0851988679]. I may have quoted out of context so here is the complete statement from that section dealing with fruit set: The reference appears as follows: Hopefully a reader with access to the latter publication can shed light on the findings leading to the author's statement.
I would not think that means Navels react more to stress, just because they have June Drop at temperatues at or above 104F (40C). Navels are normally grown at lower temperatures. Lettuce would not do good at 104F, so does tht mean lettuce react more to stress. Minneola Tangelo would not do good at 20F (-6C), I wonder if Davies would think that Minneola's react more to stress? - Millet
Junglekeeper, BTW how would you rate the book, on a 1 to 10 basis. With 1 being worthless and 10 meaning Great. - Millet
Millet, I'll reserve judgement until I've completed my second reading. However I can say it is not anywhere near the caliber of Biology of Citrus.
A better than avarage book is "Citrus Growing In Florida," It is a text book that Dr. Manners uses at Florida Southern College in his Citrus classes. Although it is about trees growing in Florida, it has some good information for Citrus being grown anywhere. - Millet
Thanks. I've read this book already but intend to read it again. As I recall its target audience is commercial citrus growers in Florida. Nevertheless there's always useful information to be found. I just noticed F.S. Davies, co-author of the aforementioned book, also co-authored this book.
It was a mistake to compare Citrus to Biology of Citrus as they have different intended audiences. The series title, Crop Production Science in Horticulture, is appropriate as the book "describes the scientific basis of production practices and is aimed at professionals in the industry as well as advanced students of horticulture and allied disciplines within plant science and food science."(*) While information on the biology of citrus is found in the book it is but a very small portion of it. What makes BoC such a great book is its thorough coverage of the topic - it is information that any citrus grower can use and appreciate. I found it difficult to focus while reading Citrus not necessarily because it is poorly written but rather the content was mostly not of interest to me. Issues of orchid management, comparison of culture in areas at different sea levels, etc., was simply non-issues for me as an indoor grower. The following is an abbreviated table of contents to help you decide whether the book is of interest to you: History, Distribution and Uses of Citrus Fruit Taxonomy, Cultivars and Breeding Environmental Constraints on Growth, Development and Physiology of Citrus Rootstocks Plant Husbandry Weeds, Pests and Diseases Fruit Quality, Harvesting and Postharvest Technology * Quote from the jacket of Citrus.
