The Domestication of Plants And Line Breeding

Guaranteeing The Colour Of Seedlings
Nothing is more damaging to the popularity of Clivias than waiting for up to four years for a flower, and then finding that it is not the expected colour, but instead, the dominant colour, orange.

Offshoots, (suckers), from a mature Clivia plant are genetically identical to the parent, but relatively few such offshoots are produced. Tissue culture, the means of mass producing most other garden plants, is not yet effective with Clivias so that most Clivias are grown from seed.

Some 9000 to 10000 years ago, with wild emmer wheat growing in the "fertile crescent" (South Western Asia), there was strong selection pressure for plants where the ripe seeds fell to the ground. But, because of a single gene mutation, a small percentage of plants retained the ripe seed in the ear. It was these seeds alone that hunters/gatherers were able to harvest.


The shaded area is the "fertile crescent" containing the wild grasses.	Emmer Wheat	Einkorn Wheat
By planting only these seeds, after a number of generations, almost all plants in the "crop", retained their ripe seeds. Thus the direction of natural selection had been reversed by 180 degrees (this is regarded as the first major human "improvement" in any plant, which created the basis for the beginning of agriculture in the "fertile crescent").
In America by about 5000 BC, the wild grass, teosinte, had an ear 1cm long. By the same process of repeated selections (line breeding) not only has the taste and nutritive value of maize improved, but by 1500 AD the cob had obtained a length of 15cm, and today, up to 45cm*. For all wild plants, there is strong selection pressure for variability eg. some seeds will germinate immediately, others will be delayed (by germination inhibitors): there will be variation in plants size and flower shape and colour. This variability ensures, that what ever the environmental circumstances, at least some seeds will grow and reproduce. Variability in all domesticated plants is greatly reduced by “selective line breeding”: selecting as parents only those plants with the desired characteristics and repeating this over several generations. This method used over thousands of years, sometimes unintentionally, for domesticating all plants and animals, is now used most intentionally by modern plant and animal breeders.		On the left - teosinte, and on the right the modern corn cob
Specifically with the Clivia, it is obvious that the plant size and vigour, flower shape, colour and size etc... can all be improved by selective line breeding. Another aspect which effects growers like this Nursery is delayed germination - with varieties not far removed from the wild, up to 30 percent of the seed may not germinate for 6 months. The process of the domestication of plants and animals is brilliantly described by Jared Diamond, Guns, Germs and Steel Vintage Books, 1998. The research shows that, for any plant, at least seven generations are needed to produce relative uniformity. For a plant like the pansy, these seven generations take little over a year. But the Clivia generation is five years. With few exceptions, no Clivia has been selected for more than five generations, but even this ensures over 95% reliability. The RHS Award of Garden Merit* The Royal Horticultural Society, (London), possibly the world's paramount garden organisation, has an “Award of Garden Merit” given when a plant has undergone a period of assessment, and meets the following criteria: • excellent for ordinary garden use • of good constitution • readily available in the horticultural trade • not particularly susceptible to pests and disease • does not require specialized care other than the provision of appropriate grooming conditions • not subject to an unreasonable degree of reversion in its vegetative characteristics Line Breeding vs. Hybridising In the early 90's, there were a number of pioneer line breeders - in Australia and California as well as China, western Europe, and South Africa who devoted decades to the development of homogeneous strains of Clivias - essentially for gardeners and popular use. Most of these breeders have now died or retired, and the same work today is being carried on by a relative few. Starting in the 1970's with two wild yellow miniata varieties, Jim Holmes in South Africa, by selection developed a pure and consistent yellow strain "New Dawn". By further continuing selection he has developed a deep yellow "Butterball" and very pale cream "Snowball" and "Snowflake".

New Dawn	Butterball	Snowflake
Particularly as a result of email chat groups, “enthusiasts” (ie some specialists) rather than gardeners, have tended to become the clamorous, more immediate, if transitory and much smaller worldwide market. New forms, which can be owned and named, are produced by hybridising the crossing of different selected parents. This again is a most basic breeding procedure, but even if the parents are selected very carefully, the result is that for every desirable outcome, there are many more undesirables. This inevitable result is not being stated on the websites of many new breeders, and many newcomers expecting every seedling to be an “instant” new variety, soon become discouraged. This Nursery is the only Clivia nursery in Australia, possibly the world, to guarantee the colour of a limited number of varieties that have been line bred and hence meet the Award of Garden Merit criteria. The Results of Hybridisation The Nursery offers over 150 different varieties, and of these, less than 25% are colour guaranteed. The rest are either the result of self crosses or crosses from two different cultivars with the intention of producing new and desirable hybridised forms. As with understanding such breeding outcomes for other plants and animals, the matters are ultimately very complex, but there are a number of general principles: The Colour Yellow In Australia, at present 'yellow' and its selected variants, 'deep yellow' and 'pale cream' is currently the most sought after colour. It arises from the mutation of only one gene, so that a seedling is either yellow, or it is not, (orange). At the early two leaf stage, yellow seedlings have a green, (non-pigmented), stem, whereas the dominant orange seedlings have a mauve, (pigmented) stem. The reputable grower/seller then weeds out the proportion of oranges.
	A series of Clivia seedling with different coloured stems. From left to right are: a yellow interspecific, a variegated yellow miniata, a yellow miniata, and orange miniata, variegated orange miniata, and caulescens.
Pink At the early two leaf stage, yellow seedlings have a green, (non-pigmented), stem, whereas the dominant orange seedlings have a mauve, (pigmented) stem. The reputable grower/seller then weeds out the proportion of oranges. Pastels are becoming increasingly popular. Typically they have muted colour and a large pale throat. They are being line bred, but the colour continues to be unstable, and can range from pale orange to peach to pink to red etc…

Pink	Pastel
Peach Peach is also a single gene mutation recessive to orange but which tends to dominate yellow. In practice, peach by yellow crosses yield some peaches, but mainly a variety of soft pink-peach shades intermediate between peach and yellow.

A typical peach	A typical yellow x peach
Red “Red” is the product of a number of genes and consequently is more difficult to obtain. A red crossed with itself or another red produces a range of shades from orange to dark orange to red. Line breeding increases the probability of red seeds, but there will always be some oranges. Cost Of Seeds Yellow seed from the world's best breeders currently costs approximately AUD$2.50 a seed - the cost arising largely from the years of line breeding. But some large Australian wholesale nurseries buy overseas seed that is 70% yellow, (often only one generation from the wild, so it is also variable in many other ways), for 50 cents a seed, and sell the seedlings to some of the large chain stores. The consequences are obvious. These introductory comments are only of very limited assistance to the breeder. For example, in practice, there is more than one mutation giving rise to yellow and to peach. They also do little to explain complex colours e.g. “Appleblossom”: cream with a pink tinge on the petals. Often the hybridiser will have only one desirable plant, (with just a few flowers), from the hundred or so in the batch of seedlings. Crossing it with itself might produce fifty or so seeds. But, as well, putting the pollen on a number of yellows greatly increased the probability of replicating the plant, because the colour characteristics will tend to be dominant to yellow. These progeny are termed 'split for yellow'.

Appleblossom
HYBRIDISING AND LINE BREEDING GO TOGETHER The “improvement” of domesticated plants comes largely from the innovative few, but the test of this improvement comes from their usefulness to the many. eg: new Dahlia forms are created by the minority of Dahlia breeders. Gardeners now grow some of them in preference to the older varieties, but some others have flowers so large that even with support, they are quite impractical in the garden. In the same way, some horses and dogs are specifically bred to win races, and the same sort of elite performance is required of the race horse and of the greyhound. But here there is the additional factor of social prestige. Because of its cost, horse racing continues to be largely “the sport of kings” whereas greyhounds are more for the man in the street! There would be very few people who would oppose the continued bloodline breeding of race horses, but the racing industry would be first to state that it was not only concerned with a small minority of elite horses, but it was also involved with the many other uses involving the majority of horses. Both line breeding and the hybridising of Clivias is carried out by a small minority of growers, but, because the internet in particular increases the social prestige of having a new form, the Clivia in western countries (where merit tends to be measured in dollars) runs the risk of becoming the (elite) “flower of kings” rather than “the orchid of a man of noble character” (Chinese and Japanese view): see below. The present astronomical prices often paid for some "new" and "rare" Clivia hybrids can be as much a reflection of the buyers need to appear the owner of something exclusive, rather than an indication of the intrinsic value of the plant.
29/4/1999 Dear Mr. David Bearlin, Thank you very much for your letter date 19/4/99. China is the country where Clivia is most popular. The plant's name 'Kunshi-ran' (orchid of a man of noble character) is originally Japanese, and the Chinese use the same name because it suits the image of the plant. As you have guessed, the popularity of Clivia in China is of a cultural and spiritual nature. Sadly, it seems that human beings is the only species which keeps warring. There hasn't been a lot of peace time in human history, but I hope the love of plants spreads friendship among people and helps stop fighting even if only a little. The symbol of my plantation was designed by my father, with the spirit of “being grateful to nature”, depicting all animals protected by plants. I believe that it is important to maintain and never forget this idea. Many Respects, Yoshikazu (Nakamura)