Does the buddha's hand citrus have seeds?


I get ths question a lot, although so far it is exclusively asked by American gardeners. And it's a great question too as the 'mechanics' required to answer it go back to 1865 when Gregor Mendel published his fundamental laws of inheritance. Lets start with some science.

These laws are as follows:

1) The Law of Segregation: Each inherited trait is defined by a gene pair. Parental genes are randomly separated to the sex cells so that sex cells contain only one gene of the pair. Offspring therefore inherit one genetic allele from each parent when sex cells unite in fertilization.

2) The Law of Independent Assortment: Genes for different traits are sorted separately from one another so that the inheritance of one trait is not dependent on the inheritance of another.

3) The Law of Dominance: An organism with alternate forms of a gene will express the form that is dominant.

That is the science part over and now I will attempt to explain this in simple English.

Botanical illustration - Citrus Buddha's hand
To begin with, the unusual fruit shapes of Buddha's Hand citrus are the result of a naturally occurring plant mutation. In horticulture this is known as sport, break, or chimera, and with plants species these naturally occurring genetic mutations can change the appearance of the foliage, flowers, fruit or stems. You night be surprised to know that there are many instances of this in nature and is in fact surprisingly common. So much so that these natural sports include the majority ornamental plants found in your local garden centre! So in the instance of the Buddha's Hand citrus this variation in the genetic code has resulted in the thickness and over extension of the fruits rind to give the Buddha's Hand effect. So Citrus medica and the cultivated varieties of Citrus medica 'Buddha's Hand' are the same species and not different species although they clearly have different characteristics. This is also exactly the same situation with cabbage, cauliflower, kale, brussels sprouts, collard greens, and kohlrabi. All of these vegetables are, in fact, the same species - Brassica oleracea. They clearly look different due to generations of selection by gardeners but they are all man-made cultivated varieties (or cultivars) of the same species. To be specific, a cultivar is a plant variety that has been produced in cultivation by selective breeding. It is not a new or different species.

So back to whether the Buddha's Hand citrus has seeds. In countries such as the USA it is often and incorrectly considered as one variety, and that this variety does not produce seeds. However in China (for example) there are actually at least a dozen named Buddha's Hand varieties or sub-varieties currently under cultivation. All differing in fruit shape, colour and size, and the tree's growing habit, etc. yet all under the umbrella of  Buddha's Hand. As something of a botanical anomaly, they tend to not produce as much seeds as the species Citrus medical but this will vary dramatically from each specific variety (with a few cultivars producing a large number of seeds) but to say none of them would produce any seed at all would be quite incorrect. So while it is true to say that Citrus medica var. sarcodactylis generally rarely produce seeds (there will always be a seed produced periodically because, as Dr. Ian Malcolm said, life will find away - even triploid cultivars like Apple 'Brambly' will produce the odd seed when theoretically they shouldn't) it is equally true that the variety “Muli” or “Xiangyanggo” does produce seeds. A quick glance at the Wikipedia page for Buddha's Hand will corroborate this for you. 

Citrus medica var. sarcodactylis
The thing to remember is that the traditional Buddha's Hand is genetically and unavoidably Citrus medica and the wide range of varieties that you can find today would have, of course, originally been grown from seed. It is just that the genes for the production of fingered fruit are not dominant otherwise this unusual fruit shape would be constantly showing up in seedlings. Furthermore seeds produced from cross-pollinating different cultivars displaying Buddha's Hand characteristics will be governed by Mendelian theory fundamental laws of inheritance. This means that there will be an increased chance of germinating a seed from parent plants with the anomalous characteristics of the fingered fruits but as the genes for this are not dominant you will always have a larger chance of regular Citrus medica fruits.This makes it a numbers game. The more Citrus medica seeds you sow the more likely it is that you will produce a Buddha's hand fruit producing plant. However there is a greater chance of producing a Buddha's hand fruit producing plant using parent plants which produce Buddha's hand fruits although mendelian theory predicts that the majority of plants will show the characteristics of Citrus medica species. 

The only way to produce new Buddha's hand varieties is through seed propagation, cultivation and selection over numerous generations either starting with species Citrus medica or selected cultivars of Citrus medica. This is unavoidable as it is directly linked to the 'nothing ventured, nothing gained' proverb. In fact there is also a history of cross species fertilisation of Buddha's hand with other citrus species such as the various lemon and orange cultivars to create something new with more reliable seed production. However modern supermarket citrus varieties have such a long history of hybridizing with other citrus species that it will be impossible to produce any standard progeny.

There is of course only one way to ensure that the genetic code for your prefered Buddha's hand cultivar is transferred from plant to plant and it is to not to propagate using seed. To ensure this you can only propagate vegetatively using cutting, grafting and micro-propagation techniques.

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