1. A valuable mutation. The ministry of agriculture in Venezuela has received numerous requests from the farmers for a variety of sweet corn which would do well under tropical conditions. There has been no way of filling these requests, however, because Venezuela has no sweet corn of its own, and all the imported varieties have failed to give desirable results.
There are at least two trays of getting good sweet corn for this country. One is to import unadapted varieties of sugar corn and cross them with the adapted varieties of starchy corn and continue selfing and backcrossing until the sugary character becomes established in an adapted variety. Another method is to make a large number of selfs in the best varieties of starchy corn and watch for the appearance of sugary as a result of a mutation. This is the procedure that was chosen, mainly because inbred lines were needed anyway for the production of hybrids. In September, 1939, 135 varieties of open-pollinated corn from various countries were planted to select the best ones and to make selfs.
During the first two generations of inbreeding, there were no mutations to sugary in approximately 3,000 selfs. In the third generation, however, in which there were approximately 1,500 selfs, two ears segregated for sugary. One of these was in the best inbred line that had been developed from an open-pollinated variety from Cuba and is probably sugary-1 (su). It segregated 216 Su to 72 su. The other sugary appeared in another inbred line from the same source and may be suam. This ear had 478 kernels of which 10 were very sugary, 106 had a dull endosperm, and in the remaining 362 kernels there was a continuous gradation from slightly dull to clear endosperm. Test for allelism with known stocks of su and suam will be made.
Some of the seeds from these two ears have been planted and there should be no question about the development of suitable sweet corn varieties in the near future.