FREEZING INJURY OF MAIZE SEED

Abstract

Maturity of the crop is the primary factor determining the damage done by frost. Freezing temperatures kill the foliage and stalk of immature plants, thus stopping translocation to the partially developed grain. The grain itself may be damaged with lowered keeping qualities and viability. Injury is especially serious to the hybrid seed corn industry where expensively produced seed may be reduced to low grade feed. Freezing injury to plants has been divided into sudden killing by intracellular crystal formation, and slow desiccation and precipitation of the protoplasm when moisture is withdrawn by intercellular ice formation. Levitt (3) and Luyet and Gehenio (5) have published extensive reviews of the theories of cold injury. Kiesselbach and Ratcliff (2) conducted a study of freezing injury to open-pollinated seed corn from 1913 to 1920, but open-pollinated varieties have been replaced by hybrid corn for which there are few data on frost injury. The present study was undertaken to determine the effects of temperature, moisture content of the seed, length of freezing period, variety of seed, physiological maturity, rate of freezing and thawing, repeated freezing and thawing, and rate of drying on freezing damage to hybrid maize seed. Yields of corn grown from frozen and unfrozen seed were compared. Materials and Methods Experiments with soaked seed