The inheritance of seed color and pattern often is rather complicated. The anthocyanin colors depend for their expression on a few "basic" genes, which can be suppressed by a dominant inhibitor. The depth and shade of color result from a number of independent genes that complement each other. On this complex are superimposed the genes for pattern, whose effect often is affected by the point of seed attachment. Color and pattern are useful in the identification of seed as to variety.

Tenderness of the seedcoat is important for any crop whose seeds are consumed. Tenderness often is associated with thin seedcoats, and thickness increases with maturity. Comparisons should be made at equivalent stages of maturity, as determined by content of dry matter. The puncture test is not so accurate as weight determination. In sweet corn, the tenderness of the pericarp is inherited on a multiple-factor basis.

TESTS FOR sweetness, consistency, and flavor also are essential in selecting sweet corn for improved quality.

Success in selection for high germination and vitality of white-seeded beans suggests that the color genes are not primarily involved but are linked on the same chromosome with other genes that affect viability of the seed. Once the linkage is broken, the white-seeded beans germinate and grow as well as the colored.

Some lines of sweet corn produce a good stand early in the season while growing conditions are still unfavorable. This means that such lines germinate and grow well at relatively low temperatures and resist the attack of soil organisms that cause decay. Tests that try to reflect such conditions are the basis for selection.

Seed dormancy is valuable in moderation, but it may be disastrous in either extreme.

Total lack of dormancy means premature germination before the seed matures properly. Many genetic factors can be responsible for premature germination in sweet corn. Sometimes the supplemental effects of two or three recessive factors are required. Some of these genes affect the plant adversely.

Dormancy results from a physiological influence of some part of the seed on the embryo or some condition within the embryo itself. In cabbage, this influence is concentrated in the seedcoat. Individual seeds vary as to the degree or length of dormancy under conditions that are favorable for germination.

Dormancy that is unduly extended interferes with normal crop procedures. Some lettuce may even remain dormant until vitality is lost.

LONGEVITY of seed is an important consideration in the selection of desirable lines. Certain homozygous recessive characters reduce the vitality of corn seed after a relatively short time.

Seeds of cool-weather crops that are planted in late summer must be able to germinate at high temperatures. Four varieties of head lettuce Imperial 456, Imperial 17, Imperial 101, and Great Lakes germinate better at 79 than do Imperial 44 and Imperial D. All germinate better at this temperature than does Imperial 615.

Seed defects of snap beans have been greatly reduced in recent years through breeding. So-called hard seeds, while normal in appearance, are undesirable because they lack ability to absorb moisture readily when planted. This delays germination to the detriment of production. Hard seeds also require more cooking. Differences among individuals and breeding lines in this respect permit its elimination through selection.

Split seedcoat occurs in lima beans, snap beans, and soybeans. Soybeans also have a netted cracking of the seed-coat. All such defects result from the presence of recessive genes. Cracking of the seedcoat after wrinkling occurs in the concentrated Fordhook variety of lima bean. Fordhook 242 is little affected.

Deformity of the cotyledons in snap beans can be minimized by selection. This and other defects contribute to difference between varieties with respect to the amount of thresher injury, which has been greatest in the newer high-quality varieties, such as Top-crop and Wade. White-seeded varieties usually appear to be more susceptible to thresher injury than those with colored seed, but the exceptions hold promise for the development of improved new white-seeded varieties. Differences in the amount of thresher injury have also been found among varieties of lima beans.

Yield of seed among the seed-consumed crops has received much attention. In sweet corn, it is related to number of rows and number of kernels per row, but from a practical standpoint the desirable ear size is largely determined by fresh market requirements. An ear just above medium size is preferred to one that is either larger or smaller.

A high yield of seeds is important in such crops as peas, black-eyed peas, field beans, and lima beans. The most effective method of increasing their potential yields has been to breed varieties that are resistant to diseases.

JOHN H. MARTIN has been a research agronomist of the Agricultural Research Service for 46years. His experience, in addition to research in crop breeding and crop production, includes the cleaning, testing, and merchandising of seeds.

S. H. YARNELL is geneticist in charge of the Regional Vegetable Breeding Laboratory of the Agricultural Research Service, Charleston, S.C. From 1930 to 1947 he was head of the Horticultural Department of the Texas Agricultural Experiment Station.