Breeding for higher oil content is inherently self-defeating because synthesis of oil is an energy wasting process compared to starch synthesis (an input of approximately two calories is required to create oil containing one calorie). High-oil corns experience yield loss per hectare as compared to low-oil corn. Because corn is regularly bought and sold in the market on a weight basis, few would be willing to produce and sell high-oil types if they produce less tonnage unless a premium is paid. Therefore, efforts are being made to enhance oil content without compromise to yield potentiality of the genotype. The average grain yield of the high-oil hybrids reduced by 5% compared to normal hybrids. Grain yield of high-oil hybrids usually decreases as oil level increases greater than 8%. Grain yield decreases at 5-10%, (some cases may be as high as 20%) can be expected with HOC hybrids.Variation in total oil content has not been found to be associated with total protein content but was positively correlated with percent germ protein and relative concentration of tryptophan in the kernel.

Association of increased oil content with reduced ear length, smaller ear diameter, lighter kernel weight, reduced plant height and ear height and early flowering has been reported. The association of reduction in grain yields with increased oil concentration may relate to the mutual exclusiveness of high-oil concentration and high grain yield. The genotype of the sporophyte greatly determines the amount of oil produced by high-oil hybrids so that these hybrids may have a more efficient energy trapping system. Oil content and calorie yield per plant are not always associated in hybrids.

Xenia Effects : The term xenia refers to immediate influence of pollen grains on the non-maternal tissues or germ and endosperm of seed plants. Xenia effects exist in corn for total oil content. It has been concluded from xenia studies that female parent had the largest influence on oil percentage of the kernel, and pollen source (Xenia) had a consistent, relatively small effect on the same. The xenia effect observed possibly resulted from an increase in grain size and increased oil concentration in the germ as high-oil content of the pollen source increases the proportion of germ in the kernel. The same relationship holds true for the percentage of oil in the germ. The xenia effects in high-oil corns can cause problems in growing performance trials with hybrids ranging in oil levels from 4-10%. Under open pollinated conditions the oil levels of the lower oil hybrids will be increased and the oil levels of the higher oil hybrids will be reduced because of xenia effects.

Environmental Effect on Oil Content: Location, date of planting and crop management have been reported to influence oil content in high-oil genotypes partially. Higher doses of N, P and K influence grain yield and in turn may influence oil production per hectare. Though environmental factors affecting oil values of high-oil corn hybrids reported effect of genotype on oil values seems to be greater.

Caloric yield increases may be small. For example a hybrid with 8 percent oil will produce approximately 3% more calories per acre than a hybrid with 4.5% oil where both have the same yield.

Marketing opportunities and prices must be known before planting. There is no established market for high-oil corn. So price fluctuation must be anticipated before planting high-oil corn to the field. It is always recommended to sow high-oil corn with a buy-back agree¬ment with the industries.