1. Growth of inbred and hybrid maize.

The growth of inbred and single and double cross maize hybrids in tems of both fresh weight increase and dry weight increase was studied during the germination period and the early post‑germination period in one instance and during the grand period of growth and the maturation period in another instance. No relation was found between size of the embryo and/or size of the seed and the ultimate size of the shoot of the plants developing from the embryos.

A method was developed for the determination of the relative efficiency of the protoplasm synthesizing processes of the inbreds and the hybrids. The hybrids were found to have relatively more efficient protoplasm than the inbreds. In every case where the hybrids exhibited distinct vigor, this vigor was associated with an early attaiment of rates of fresh weight and dry weight increase higher than those of the inbred parents. Double cross hybrids showed no distinct growth advantages over single cross hybrids but did exhibit greater uniformity.

W. Gordon Whaley