FACTORS AFFECTING GRAIN DRY-DOWN IN EARLY-MATURING EUROPEAN AND CANADIAN CORN HYBRIDS

Abstract

Twenty-two corn (Zea mays L.) hybrids of European (EUR), of Canadian (CAN) and of Canadian origin but of European phenotype (CPE) were compared for factors affecting rate of dry-down over 11 location-years (1977–1979) in Manitoba and Ontario. Percent kernel moisture (PKM) of CAN hybrids at 20–30 days postsilking was equal to or higher than that of EUR hybrids; 40–60 days later PKM was at least 3% lower for the former compared to the latter. Differences in resistances to kernel water loss among hybrid groups were related to differences in husk and pericarp characteristics. Husks of the CPE hybrids senesced approximately 8 days before those of the EUR hybrids and weighed less. In a 2-yr husk modification experiment involving hybrids of CAN and EUR classification, PKM at final harvest of Limagrain 11 (EUR) with husks completely removed was reduced to a value similar to that of the control of Stewart 2300 (CAN). Pericarp thickness of CAN and CPE hybrids was 80–85% of the mean thickness of the EUR hybrids.Key words: Dry-down, early corn, European, Canadian