SYNOPSISYield comparisons of two corn hybrids, W240 and W255, grown at Wageningen, Netherlands, and Spooner, Wis., showed maximum yields averaging 110 bushels per acre at Wageningen and 68 at Spooner; 5·year averages for W240 were 86.1 and 62.9 respectively. Higher plant populations (28,907 per acre at Wageningen, 11,784 in Wisconsin), uniform rainfall distribution, higher soil fertility, and lower disease incidence contributed to high yields at Wageningen. The stage of maximum maturity required up to 9 more weeks growing season and occurred as much as 6 weeks later at Wageningen than at Spooner.

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The method generally adopted to produce hybrid seed corn is to plant the parent varieties (inbred lines or foundation single crosses) in an isolated crossing plot .The principal condition that must be fulfilled in order to bring about the desired crossing is, that the partners flower simultaneously . This condition is not always satisfied . Sometimes it is the pollen parent which comes in bloom too early and has shed its pollen before the seed parent has started silking . In the reverse case, the seed parent may be in full silk, whereas the male partner has not even shed one pollen grain . This situation has caused the failure of many seed production fields and seedsmen have long been looking for methods by which the flowering time of certain inbreds or single crosses can be synchronized . The difficulty is increased when the required cross is between two varieties differing markedly in maturity . In Holland, where dent-flint hybrids play an important part, this problem must be faced every year .There are two obvious possibilities of removing the obstacles :l . to make the late varieties flower earlier .2 . to retard flowering of the early varieties .Flowering might be advanced by (a) adjusting the day length or (b) by sowing early in a greenhouse or cold frame and transplanting later to the field .The method mentioned under (a) will be left out of consideration as it would not be applicable on a large scale .The last method (b) has been applied rather extensively by one of the private corn breeders in our country, the late MR BENNINK . Seeds of inbreds to be forced were planted in small pots moulded from a mixture of clay, sand and cow dung . The young plants were kept under glass until they had developed 2 or 3 leaves and then transplanted into the fields with pot and all . Provided that seeding and transplanting had been made at the proper time, it was possible to induce certain strains to flower a few days earlier than under normal conditions . This method is limited in its scope . It requires much labor and can only be used in small plots to be planted with valuable material . For large scale work this method is far too expensive .

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