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Issue link: http://read.dmtmag.com/i/693015
www.stma.org July 2016 | SportsTurf 35 stars in the universe; but that statement seems to lose its impact unless you do the math, so let's do the math (see above). There are approximately 700 trillion cubic meters of beaches on planet Earth, and using an average medium sand particle size that is equivalent to 8,000 sand grains per cubic centimeter, that equals 5 quintillion (5 x 1018; in this decimal notation, 1018 is a 1 followed by 18 zeros) grains of sand on all the beaches of planet Earth. Now, there are approximately 250 billion stars in our Milky Way galaxy, and there are approximately 200 billion galaxies in the known universe. That equals 50 sextillion (50 x 1021) stars in the universe (give or take). These are very large numbers of things, too large really to even comprehend; however, they pale in comparison with the number of genetically unique individuals of sexually reproducing species, like creeping bentgrass. To estimate the number of genetically unique individuals of creeping bentgrass, we'll apply a standard genetics formula that uses the number of different combinations of different forms of any given gene to the power of the total number of genes that an organism possesses. On average, this number is 1 x 1030,000, or 10 different combinations per gene to the power of 30,000 genes per organism. I don't even know that there is a name for this number, but I do know that it is a very large number. Finally, of the total amount of all this genetic variation within the creeping bentgrass species, approximately 2/3 of the genetic variation have been found to reside within cultivars, while 1/3 has been found to reside between cultivars. And thus, if we assume that there are roughly 200 cultivars of creeping bentgrass in today's market (there really aren't that many, but it helps to make the numbers work better), then the total number of genetically unique individuals that might exit within the Penncross cultivar would roughly be on the order of 1 googol (or 1 x 10100; that is a 1 followed by 100 zeros). Thus, there is way more number of genetically unique individuals of Penncross creeping bentgrass, or any cultivar of creeping bentgrass for that matter, than there are stars in the universe. The point of this exercise is to illustrate the importance of managing your young seedling plants during establishment. If, for example, you plant creeping bentgrass, which possesses 6 million seeds per pound, at a recommended rate of say 1 lb. per 1,000 sq. ft. on an average sized golf course putting green of 5,000 sq. ft., then your initial establishment will give you 30 million genetically unique seedlings. Over time, it is unrealistic to believe that all 30 million seedlings will survive. Some seedlings will succumb to disease, other will die from heat or cold, and many will simply be outcompeted by their neighboring brothers and sisters. There is immense competition for the limited resources of light, nutrients, water and simply space to grow on a golf course putting green. Therefore, over 1 x 10 100 GENOTYPES in PENNCROSS More than 2/3 of all creeping bentgrass genetic variation resides within cultivars divided by approximately 200 cultivars. 1 x 10 30,000 GENOTYPES of BENTGRASS (Number of allelic combinations) # of genes 5 x 10 22 STARS in the UNIVERSE 250 billion stars in the Milky Way x 200 billion galaxies 5 x 10 18 GRAINS of SAND on BEACHES 700 trillion m 3 of beach on Earth 8,000 grains = cm 3 (1 cm 3 = 0.06 in 3 )