| Popis: |
Corn (Zea mays L.) grain yield is sensitive to water availability from emergence to maturity. Using early-maturing corn hybrids might avoid the late-season stress that frequently occurs with dryland culture. This research was conducted to determine whether early-maturing corn hybrids could yield similarly to late-maturing hybrids under dryland conditions. Field studies were conducted at Mead, NE, on a Sharpsburg silt clay loam (fine, montmorillonitic, mesic Typic Argiudolls) in 1991 and 1992. In Lincoln, NE, the soils were a Kennebec silt loam (fine-silty, mixed, mesic Cumulic Hapludolls) in 1991 and a Crete silt loam (fine, montmorillonitic, mesic Pachic Argiustolls) 1992. Three early-maturing (95 to 99 d) hybrids and three late-maturing (114 to 118 d) hybrids were grown at 10 000, 18 000, 26 000, and 34 000 plants /acre. Little late-season water stress occurred in 1992, thus, hybrids produced high yields that increased with increasing population up to 26 000 plants/acre and even 34 000 plants/acre. However, substantial late-season water stress occurred in 1991. Environments dominated by late-season water stress caused yield reduction at high plant populations for all three late-maturing hybrids and one early-maturing hybrid. Two of the three early-maturing hybrids produced similar yield responses to increased plant population, independent of degree of late-season water stress. This indicates use of well adapted early-maturing hybrids might improve yield stability, since their response was not dependent upon yearly weather conditions, in contrast to the late-maturing hybrids. Two early-maturing corn hybrids did not consistently yield comparably to late-maturing hybrids. These two early maturing hybrids appeared to lack the water stress tolerance and yield potential required to consistently yield comparably with late-maturing hybrids. However, the early-maturing hybrid, Pioneer 3737, produced grain yields comparable to late-maturing hybrids in nearly every instance. These results indicate a well adapted early-maturing hybrid can produce yields comparable to or better than late-maturing hybrids, particularly where late-season water stress is prevalent. However, the optimum plant population may be higher for early-maturing compared to late-maturing hybrids. |
Plný text