Teosinte is widespread on the South side of Toluca from Metepec to Rayóu (Long. 99? 37', Lat. 19? 10'-15'), a distance of 11km, on the road Toluca-Ixtapan de la Sal in the State of Mexico. How could this population exist for so long without being discovered? For starters there are only cultivated fields and teosinte exists as a corn mimic in a fashion comparable to Chalco in the Valley of Mexico. There are no hillsides with wild populations. Secondly, teosinte is of short stature comparable to the maize in the fields, Conico. In all other maize-mimetic coevolutions teosinte is a tall plant and may exceed the height of the maize. Lastly teosinte around Toluca dries a gray brown, the same color as Conico. All other teosinte populations dry a bright tan, which is several shades lighter than maize and easily spotted. This color difference led to the discovery of the Ciudad Hidalgo population by me thirty years ago.
How I could have missed the Toluca population for so many years is beyond me. A week before the discovery I had driven alone the exact same road and not seen it. A week later Sukitoshi Taba was driving and I was watching the fields which were near harvest condition and I said "that's teosinte" and we both agreed it couldn't be because it had never been reported in the valley, and then there were more plants and we continued to see plants for 11 more kms, from 2600m to 2800m, which is higher than teosinte populations above Amecameca in the Valley of Mexico. The Valley of Toluca teosinte populations on the side of the Nevado de Toluca are the highest in elevation of all teosinte populations in Mexico and unique because they are such excellent mimics of the maize race Conico. The seed is very large and comparable to the race Chalco. At the present time we do not wish to make a racial determination for the population. Professor T. Kato, T is currently studying the chromosome knob positions, which should help resolve the racial classification question.
The significance of this discovery is that so many of us have driven by but not seen the population. This begs the question, are there more regions in Mexico yet to be discovered that we have repeatedly driven by and not seen? Seed of this population can be supplied by Dr. Sukitoshi Taba, Head CIMMYT Maize Germplasm Bank, Lisboa 27 A.P. 6-641, 06600 Mexico D.F. Mexico.
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