YIELD, QUALITY, AND NITROGEN USE OF INBRED CORN WITH VARYING NUMBERS OF LEAVES REMOVED DURING DETASSELING

Detasseling is used in hybrid corn (Zea mays L.) seed production to en sure harvested seeds have the desired genetic complement. Both mechani cal and hand detasseling result in loss of some leaf tissue and plant N. The objective of this study was to determine if seed yield and qual ity and N content of grain and stover were affected by leaf removal du ring detasseling, The treatments evaluated were removal of tassel only , tassel plus one leaf, tassel plus two leaves, tassel plus three leav es, tassel plus four leaves, and no tissue removed (control). The leaf area index (LAI) declined linearly, about 0.16 LAI units per leaf rem oved. Grain and stover yield also declined Linearly with number of lea ves removed with the tassel (r(2) = 0.97 and 0.92, respectively). Each leaf removed reduced grain yield about 0.36 Mg ha(-1). Yield reductio n was caused by decreased kernel size. Grain and stover N concentratio n and amount of N in stover did not vary among detasseled treatments. However, total N in the grain declined linearly as number of leaves-re moved increased (r(2) = 0.97). Warm and cold germination and warm germ ination after accelerated aging were not affected by leaf removal duri ng detasseling. Results reported here suggest that when leaves are rem oved from the plant at detasseling, the loss of photosynthetic capacit y, the ability to intercept light, and plant N all contribute to grain yield reduction.