The whole group of plants we lump under the taxonomic classification of citrus are really changeable. It's out of this changeability that we get new varieties. Some of these can be quite fanciful, almost dream like fruit which is where the origin of the name chimera comes from. Buddha's Hand is a pretty dream-like fruit.
These changes are a genetic mutation that occurs in a branch or twig, and if that tissue survives, it can produce new shoots (called sports or chimera) with characteristics different from the those of the mother tree. These mutations can affect the color of the rind or pulp or the shape of the fruit.
Leaves on these twigs can have a different shape or size have a variegated color.
Mutations can cause the development of multiple buds, creating bunchy growth or “witches' broom.”
A chimera can produce an improved crop: some of today's cultivars were propagated from chimeras, such as the variegated pink lemon.
Usually sports are of inferior quality and should be avoided as propagation material. Prune sports that obstruct normal growth or interfere with harvest.
But some of them are so weird you just want to keep them around. This one showed up on one and only one tree branch in a lemon orchard. It looks like citrus scab, sort of, but on only one branch of one tree.
Some of the changes that you see in a tree can also be symptoms of a whole lot of other problems, like nutrients, Huanglongbing or herbicide damage. Check out some of the symptoms:http://ipm.ucanr.edu/PMG/C107/m107bpfruitdis.html
Some chimeras are yet to be found out. This image of spiral tattooing showed up for several years ago in a Meyer lemon orchard. It was erratic and inconsistent in a tree, not typical of a chimera. The orchard was finally removed because it wasn't making money. Now it just seems like a dream and will never know if it was a true chimera.
The first years of a tree's life are for building a structure for the future. Many varieties of trees are precocious and will bear fruit when they should be building structure. Letting a tree carry fruit when it is too young (under 2 years of age in the ground and some say 5 depending on the tree species) delays future good production and distorts the tree's architecture. A young avocado tree can be completely humbled (brought to ground literally) by the weight of the 12 ounce fruit. ‘Lamb Hass' wants to grow upright, but if the young tree is burdened with fruit early on, it will grow squat and twisted.
Another problem with precocious trees recently came up with ‘Meyer' lemon. Along the coast, this is a tree that will carry fruit throughout the year. It is a small tree naturally, but also because it puts so much energy into fruit production. If allowed to fruit to its full potential early, the canopy development is delayed and the fruit grows unprotected from winds. It is much more subject to wind scarring. Imagine the wind flailing the fruit around with no branches or leaves to protect it. Now the grower has a small, twisted fruit tree and fruit that can't be sold.
Give your young trees a chance to grow without the burden of carrying fruit to early. They are your children.
Imagine all this fruit on a one year old canopy
And this fruit is fully exposed to the elements and wind scarring
Citrus is a messy botany. It loves to cross with anything and in so doing creates very complex ancestry. C-35 rootstock is a citrange and was created for its tolerance to cold, but is also good in Phytophthora situations and creates a slightly smaller tree. Oddly, it is deciduous, a cross between Poncirus and Citrus. It's a trifoliate hybrid. 'Meyer' lemon is the same mess, a cross between a lemon and an orange/mandarin. You would think these two messed up cousins might do well, but in several instances there is an incompatibility. 'Meyer' has been grown successfully on 'Macrophylla' and 'Yuma Ponderosa', both of which are also complex hybrids.
You see the darndest things in orchards, aside from all the junk that people throw out of their cars. Here's a case where someone had a little time on their hands and tattooed some fruit in the field. Apparently it was some pointed object that scared the skin and then it healed over. Maybe this is a new marketing opportunity for Meyer lemons.
photo by S. Caughey