Monday, September 19, 2016

Designer Plants

Our post title, Designer Plants, suggests a commonly used meaning: plants of interest to landscape designers and plant retailers—beautiful, utilitarian, exotic, unusual, or even bizarre. In contrast, we use our post title as it applies to the improvement of food quantity and quality for earth dwellers. As such, we focus on how humans have improved plants to increase production of food. Food security is of vital importance for long term healthy survival of humanity. How have biological scientists handled the subject of improvement of the world’s food resources? Our web searches have revealed much information which inspires further investigation. In particular, in this post, we focus on maize (corn) as a designer plant.

Let’s make a backward leap to memories from my childhood. Hybridization became more dominant in plant science in the 1920s and 1930s. The process heightened the potential of artificial selection by which Mesoamerican Indians had developed hundreds of useful varieties of maize since 10000 BC. My father was an agent for a hybrid seed corn company which marketed their seeds as Funk’s G Hybrids until 1990.  The current Syngenta agribusiness company claims Funks G as one of their original seed firms. When my father was an agent for a Landisville PA company, Hoffman Farm Seeds, in the 1940s, he approached farmers in his agency area, New York State, with appeals to purchase the new higher yielding corn hybrid seeds. As with many new technologies, some farmers were dubious. They did not take kindly to hybrid seeds. A modern parallel is the intense current resistance to genetically modified seeds (GMOs). We refrain from discussing this complex issue in anticipation of future posts.

As an elementary/middle schooler in the immediate years following World War II, I was not especially interested in genetics of farm seeds. By default, however, I was exposed to the early days of promotion of hybrid corn seeds to farmers. Many terms were discussed by my farm seed-agent father with his friends and with me. For example, I recall discussion of “double-cross hybrids.” Many farmers did not understand what that meant. My father attempted to explain the term to them and to a 10-year old, probably without much success.

One element of success, however, was achieved by my observation of Dad’s “test plots.” These were little parcels of land devoted to planting samples of heirloom and hybrid seeds for their demonstration value. But he also skillfully piqued the imagination of farmers with some highly unusual seeds. The results were interesting rows of highly unusual corn plants. I recall the “Indian corn,” “pod corn,” popcorn, and sweet corn Dad planted on our own family lot. One variety of corn plant was over 15 feet in height. (I have pictures to prove this.) “Dent corn,” was the focus of Dad’s professional promotion: Raise the dent-corn Funk’s G hybrids G-6, and G-10, he advised, and reap better crops!

My father understood the varieties of corn which originated in an ancestral “corn” called teosinte. 9000 to 10000 years ago only teosinte existed in the key area of Mesoamerica (Central Mexico). Teosinte was domesticated and spread by indigenous groups. By 2500 BC, the Mesoamerican Indian population had deliberately selected the best plants for their future plantings thousands of times. They developed many useful varieties of maize as a result. Their “selective” breeding, centuries of selecting plants with bigger kernels, larger size cobs, and other different and more desirable forms, had contributed to the development of a trade network based on a surplus of varieties of New World corn long before explorers from the Old World arrived. By 2500 BC, precursors of today’s six main types of corn existed. The six types are flint corn, also known as Indian corn, flour corn from which corn meal is made, dent corn, the staple grain raised by farmers, pop corn, pod corn in which each kernel is enclosed in a cover, and sweet corn, a summertime table favorite.

All of these varieties originate from teosinte as we detailed in our preceding post. The remarkable origin and development of maize is inappropriately cited as an example of organic evolution as now taught in our educational institutions. They have taught that millions of modern species of plants and animals have evolved from “natural” selection and accidental mutation. Currently many more novel hypotheses are entering the evolutionary theorists’ explanatory lexicon. 

Organic evolution implies changes in genetic composition as new life forms appear.        Logically, evolutionists must explain speciation of many millions of existing species. Different species of earth life are generally unable to interbreed. On rare occasions where they interbreed, the progeny usually manifests genetic problems. Modern maize varieties easily form additional varieties by additional man-controlled selective breeding and hybridization processes because they are all of the same species.

We quote UC Berkely’s website Understanding Evolution: “Natural selection is the simple result of variation, differential reproduction, and heredity—it is mindless and mechanistic; it’s not striving to produce “progress” or a balanced ecosystem…..Natural selection just selects (my emphasis) among whatever variations exist in the population. The result is evolution.” 

This quote from the Berkeley site leaves many tenets of evolutionary theory unanswered. It also triggers new sets of questions about the broadly accepted paradigm of molecules to man evolution. Among the questions is the marvel that maize diversity is explained by subtle genetic changes in a minuscule set of only five genes in the nucleus of every maize variety currently in existence. How were these subtle changes accomplished? How is selection involved? 

The term “select” in the Berkeley quote suggests a deliberate, intelligent process directed by an intelligent mind. This explains why we titled our post “Designer Plants.” Humans have “intelligently designed” maize plants over the rather brief human time span of 10000 years. Evolution’s “mindless” and “mechanistic” selection process does not explain the wondrous development of the world’s maize by human artificial selection. Rather, we intuitively recognize our maize varieties as a biological bequest to humanity from God, the Creator of All Things.