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Corn Physiology in Short Season and Low Temperature Environments 1
Author(s) -
Lee S. S.,
Estes G. O.
Publication year - 1982
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1982.00021962007400020016x
Subject(s) - hybrid , seedling , sowing , growing degree day , biology , agronomy , dry matter , growing season , field corn , horticulture , zea mays
Northern areas seeking to expand corn ( Zea mays L.) production and thereby reduce feed costs for livestock require early plantings of short season hybrids with good seedling vigor. The association between physiological behavior of corn to low temperature and its field performance could be important in selecting hybrids adaptable to such areas. Twenty corn hybrids of commercial importance in New Hampshire which varied in maturity were planted 21 April and 19 May at the Univ. of New Hampshire Agronomy Research Station, Madhury, NH; nine selections from the above were also grown at three other locations in the state with widely differing growing conditions. The effect of controlled temperature on chloroplast structure and photosynthetic activity was also determined using the earliest and one of the latest maturing hybrids which differed in early development under field conditions. Low temperatures following the early planting of 21 April did not adversely affect stand density of hybrids; seedling growth of the two earliest maturing hybrids was superior to all other selections. At the normal planting date of 19 May seedling growth of the 20 hybrids was negatively correlated with their maturity rank; seedling growth was greatest in the earliest hybrids. Yield of total dry matter (TDM) at maturity was not related to seedling growth. In field studies in the southern and middle part of New Hampshire with a growing degree days (GDD) range of 1,100 to 1,300, TDM yields of the earliest corn hybrids were lower than yields of the later maturing corn. At the northern locations, with GDD < 1,100, yield of TDM was not significantly different among hybrids although % DM was higher in early maturing corn. A greater decline in photosynthesis and altered chloroplast ultrastructure in the leaves of a late‐maturing corn following exposure to controlled day/night temperatures of 15/10 C in the greenhouse was observed; no such changes occurred at 15/10 C either in the earliest hybrid, which had shown superior seedling performance under field conditions, or in either hybrid when grown at 10/15 C.