Through the years, men and bees have worked together to create improved flowers and vegetables.
Awe-inspiring artificial moons are drawing our attention toward the skies as never before.

Amid all this, it may be reassuring to realize that we have, or can have, more pleasantly diverting scientific marvels to ponder at arm’s length in our own gardens.
Many of the beautiful flowers and mouth-watering vegetables that we enjoy have been developed by scientific breeding methods.
Although not often widely publicized, these methods are no less noteworthy than the breakthroughs in chemistry and physics that have given us nuclear energy and man-made moons.
- Plant Genetics
- Mendel’s Principle
- Methods of Gardening
- Adaption to the Environment
- Increased Size of Flowers
- Increase of Vigor
- Disease Resistance
- Increased Productivity
- Earliness of Plants
- Commercial Seed Production
- Cross-Pollination of Plants
- Geographical Isolation
- Nectar Collection
- The Danger of Pollen Mixture
Plant Genetics
The old art of flower and vegetable seed breeding has gradually become a relatively exact science known as plant genetics.
Aims that years ago could not have been realized in a lifetime may now be planned with foresight and accomplished within a few years or perhaps decades.
It is interesting to follow some of the important milestones in the development of new plants.
Without this knowledge, we would still have only the wild plants known to the ancients in our gardens.
The nature of sex in plants was explained during the period from 1676 to 1694 about as we know it today: notably the presence and purpose of ovules and pollen and the possibilities of controlled hybridization.
The cell-like structure of plants was demonstrated clearly during the years 1835 to 1839.
Mendel’s Principle
Two new concepts evolved: first, a cell divides to form two cells, and second, those cells become specialized as growth proceeds— root cells, stem cells, leaf cells, and flower cells.
Mendel’s principles of heredity were announced in 1866 but were hardly noticed until their rediscovery in 1900.
Chromosomes were found in plant cells and studied from 1875 to 1888. Their name derives from the fact that the microscopic particles absorb dyes readily. This made for easier observation under a microscope.
Chromosomes have been shown to be the physical basis of heredity and the repositories of genes, the determining factors in heredity.
Discovery of Chromosomes
The discovery of chromosomes explained Mendel’s earlier observations on inheritance—the orderly and predictable fashion by which plant characters are expressed from generation to generation.
Ideally, a new plant should embody the most desirable characteristics of both ancestors. In 1900, and became the basis of modern plant and animal breeding.
These laws are enumerated and elaborated clearly in any encyclopedia or elementary botany book.
1) The law of dominance
2) The law of segregation
3) The law of recombination
Science of Breeding
Mendel showed that height, color, and other characteristics depend upon determining factors we know today as genes. (From the word gene came the term genetics, the science of breeding.)
Mendel demonstrated that the second and later generations resulting from crossing two different varieties exhibit characters in all possible combinations and that new varieties with more desirable traits could be developed by selection and further crossing.
From about 1903 to 1908, a special technique for producing hybrid corn seed was devised. This same method is being used today.
During the period from 1930 to 1940, plant researchers demonstrated that it is possible to cause a doubling of chromosomes by treating plants with colchicine.
Some of the treated plants exhibited strikingly larger and more deeply colored flowers on sturdier plants.
Methods of Gardening
Specialists in publicly supported state experiment stations and specialists of progressive seed companies have utilized this relatively new-found knowledge of inheritance in plants to improve both flowers and vegetables.
Some worthwhile projects in plant improvement are often accomplished within a few years; more than ten years is rarely required.
Better varieties are being developed to serve the changing tastes of consumers, the changing methods of gardening, and the changing hazards in the garden—namely diseases and insects.
A few examples will serve to illustrate some of the outstanding accomplishments in this field.
Adaption to the Environment
For years it was accepted that sweet peas could not be grown where midsummer temperatures were high and rainfall limited.
Today sweet peas can be grown in these sections because the Cuthbertson strain was developed with this in mind.
Years ago, Frank Cuthbertson of the Ferry-Morse Seed Company crossed a notably large, growing, rugged sweet pea that had little appeal otherwise with a less rugged but far more beautiful variety of sweet pea.
He was confident he could select offspring from these crosses, which would be beautiful and drought resistant.
By applying Mendel’s principles generation after generation, he finally achieved his predetermined goal.
Increased Size of Flowers
Large showy flowers are popular among gardeners, and hybridizers often seek to improve the size of existing strains.
By doubling the number of chromosomes in a given plant by chemical means, the resulting plants often exhibit increased flower size and plant vigor.
Tetra snapdragons, tetra phlox, and tetra zinnias are the product of this chromosome doubling and are widely grown today.
The handsome Gloriosa Daisy developed by the W. Atlee Burpee Company is a recent flower introduction with a doubled number of chromosomes.
Increase of Vigor
Sweet corn, other vegetables, and many flowers are now available as (first-generation) hybrids.
The technique of crossing inbred lines to produce Fj seeds has produced plants with extreme vigor and uniformity.
The second generation of these hybrid seeds (F2 ) may have particular value to the flower gardener.
Plants from F2 seed generally exhibit a wide range of colors. This is often, although not always, desirable.
Disease Resistance
Inbred capacity for resistance to disease has been achieved in many vegetables.
That it is possible to combine disease resistance with good eating quality is constantly being demonstrated.
The well-known Wade snap bean (mosaic and mildew resistant) and Manalucie tomato (resistant to early blight and other diseases) are but two examples of this dual-purpose hybridizing.
Increased Productivity
Commercial growers and backyard gardeners with limited space are interested in high yields of vegetables.
Cucumber and squash plants usually have nonproductive pollen-bearing flowers far in excess of the female flowers, which are destined to become fruits.
Some years ago, an observant hybridizer found a cucumber plant and a summer squash plant, each showing a reversal of this form—many more female flowers than pollen-bearing male flowers.
Controlled selective inbreeding of this cucumber produced excellent varieties that give maximum yields from a little space.
Inbreeding of the squash produced similar results. Typical of these high-yielding varieties is the Straight-8 cucumber, which won an All-America Gold Medal in 1935 and is still popular.
Also prodigiously productive is Early Prolific Straight neck bush summer squash, which received an All-America Silver Medal in 1938 and is still widely grown.
Early Prolific Straight neck squash has served as a parent in later crosses, resulting in wide fine varieties.
Earliness of Plants
Vegetables that mature before frost are of primary concern to northern gardeners.
About 25 years ago, Earliana was the earliest tomato available—sixty-five days from transplanting to the first ripe fruits. Bonny Best, seventy to seventy-five days, was the earliest high-quality tomato.
Now we have significantly earlier tomatoes—Early Chatham, Fireball, and Burgess Hybrid # 1.
These tomatoes have given gratifying production far into the Canadian provinces, even into Alaska.
Commercial Seed Production
Our thanks for this are largely due to the pioneering and sustained efforts of Dr. A. F. Yeager, whose research has been successfully conducted in North Dakota, Northern Michigan, and New Hampshire.
Credit also must be given to state experiment station workers and seed merchants on both sides of the Canadian border who are particularly interested in meeting the needs of gardeners in short-season regions.
When we thumb through a seed catalog, we give little thought to how the various kinds of seeds were produced.
Many pitfalls and hazards must be overcome when a new variety is developed by a hybridizer until full-scale production of the seed is achieved. A few examples will serve to illustrate this point.
Cross-Pollination of Plants
Some plants, such as sweet peas and lettuce, bear flowers that are so constructed that they are always self-pollinated in nature.
There is little chance of natural cross-pollination in these flowers with undesired pollen from nearby plants.
However, many kinds of flowers are open to wind- or insect-borne pollen and hence are easily contaminated by outside pollen.
Artificial means of preventing undue cross-pollination have been devised. Suitable shelters are used to cover a limited number of selected plants to exclude pollen carried from other plants nearby.
When producing large acreages of seed crops, other means of preventing cross-pollination must be used.
Geographical Isolation
One ingenious method is geographical isolation. This can be done in either of two ways, depending on whether the crop is pollinated by wind or bees.
For example, table beets are pollinated using wind-borne pollen. To maintain a pure strain, distinct varieties must not be grown for seed production in adjoining acreages.
However, varieties can be grown with perfect safety some miles apart. Acreages are chosen so that one variety does not lie directly to the windward of another variety, especially during the blooming season.
Some plants, such as cabbage, depend on honey bees to pollinate their flowers. A red cabbage and a white cabbage grew for seed must not occupy adjoining acreages.
The seed crop from each would yield nondescript heads because of indiscriminate pollination by bees.
In my early years as a geneticist, I learned that the term beeline can be taken at face value.
Nectar Collection
When collecting nectar, bees fly instinctively directly to their foraging area and back to the hive without much deviation from the traditionally straight beeline.
Since bees don’t discriminate between varieties of a given plant, they may visit several varieties of one flower on the same pollen-gathering trip if varieties are within their beeline.
Thus a white cabbage plot and a red cabbage plot within the same beeline would be subject to cross-pollination and objectionable mixing of pollen.
However, when such plots are placed a few miles apart in a geographical arrangement that interrupts the beeline, no mixing of the pollen occurs.
For example, picture a large equilateral triangle with the apexes a half mile or more from each other.
The Danger of Pollen Mixture
If the bee colony is placed at one apex of the triangle, with plots of Green Hubbard squash at another apex and Golden Hubbard squash at the other, the bees will not mix the pollen—the beeline has been interrupted.
Even if a bee should visit the opposite plot on an alternate trip, there is little danger of the pollen mixture.
It has been observed that bees are examined in the hive before each departure by a specialist bee who removes every grain of pollen from his body so that he departs clean on every trip.
Guided by knowledge of the beeline and other well-substantiated information on bees, we can now place hundreds of acres of seed crops at safe distances to prevent undesirable pollinations.
These are but a few of the methods used to provide better seeds for the gardener.
44659 by Gordon Morrison