Character, field performance, and commercial production of waxy corn

There is a limited demand for either imported or domestically produced starch possessing the peculiar characteristics of tapioca starch. Under current conditions the starch industry would be warranted in paying a premium, if necessary, for 50 to 75 million pounds of such starch annually, in comparison with the price of ordinary corn starch. The industry has found certain cereal crops, notably waxy corn and waxy sorghum, to be satisfactory domestic sources for the replacement of tapioca starch made from the imported cassava root. Waxy corn appears to be especially suitable for this purpose because it can be milled with the same equipment already extensively used for ordinary corn. Field performance tests have been made during 3 years, in eastern Nebraska, of several waxy corns having commercial possibilities in comparison with standard Corn Belt hybrids and an open-pollinated non-waxy variety. Of these, Iowax 1 (formerly known as Waxy Iowa 939) proved most productive and possessed superior vegetative characteristics during the 2 years tested, 1942-43. As an average, Iowax 1 was found to yield approximately 4% less than Iowa 939 and 15% less than U.S. 13 under prevailing conditions, a difference of 6% being required for statistical significance. It would seem advantageous to have Iowax 1 produced in territory where Iowa 939 is being extensively grown because of its special adaptation: Less price premium would need be paid there by the industry as a special inducement for its production than under conditions where a larger, later-maturing hybrid as U.S. 13 is superior. Because of the differences in characteristics and utilization of waxy and non-waxy starch, and the very limited specialized demand for the waxy-type starch, promiscuous production of waxy corn and its admixture with non-waxy corn should be avoided. This is best accomplished through strict contract production. With a loss of its waxy character when outcrossed, waxy corn fields should be reasonably isolated from other corn, the degree of isolation being specified by the contracting company. When grown in test plots subject to extensive outcrossing with unrelated pollen of both waxy and non-waxy corn, the outcrossed non-waxy kernels of Nebraska Waxy and Iowax 1 were 3.9 and 2.8% heavier, respectively, than the waxy kernels occurring on the same ears. No significant difference was found in the yield per acre from white and yellow waxy segregates. Comparable waxy and non-waxy segregates yielded essentially the same, and there was no significant difference in seedling emergence or vegetative habits. The observation that the waxy character may result in approximately 3% less translocation from the stalk to the grain suggests that two hybrids, identical in all genes except waxy, would differ about 3% in yield of grain per acre. This may account largely for the 4% lower yield of Iowax 1 compared with Iowa 939. Subjecting waxy corn plants to outcrossing by non-waxy pollen in varietal test plots may result in a maximum error of about 3% in the acre-yield determination, the amount depending upon the proportion of outcrossed kernels. Further tests of segregating populations confirm the earlier finds as to differential fertilization, there being a deficiency of about 1% in the total expected number of waxy kernels. Instead of 25% of the kernels on selfed segregating ears being homozygous for waxy, only 23.95% were so classified.