Nitrogen Fertility Effects on Accumulation, Remobilization, and Partitioning of N and Dry Matter in Corn Genotypes Differing in Prolificacy
1984
Anderson, E. L. | Kamprath, E. J. | Moll, R. H.
Results from previous studies have shown that more prolific corn (Zea mays L.) genotypes produce more grain per plant than less prolific genotypes. The objectives of this field study were to determine the effect of N fertility on dry matter (DM) and N accumulation, partitioning, and remobilization in genotypes which differ in prolificacy (ear number per plant). Two N rates were used, 56 and 224 kg N ha⁻¹ on a Typic Plinthic Paleudult. Eight genotypes were grown in 1978 and three in 1979. Leaves, stalks, and ears were sampled at various times during grain fill and N content was determined. Leaf dry weight did not change during grain fill at either of the N rates. Stalk dry weight increased initially during grain fill and then decreased at the low N rate, for all genotypes, but at the high N rate, only the nonprolific genotype showed the initial increase. The rate of increase in ear dry weight was constant throughout the grainfilling period at low N, but decreased after 30 days at high N. Leaf N decreased linearly during grain fill at both N rates. The decrease in stalk N was curvilinear at both N rates with most of the decrease occurring in the first 30 days after silking. Ear N accumulated at a linear rate for the first 30 days during grain fill and then proceeded at a slower rate. Grain yield per plant was associated with the number of ears per plant. Increasing the N rate tended to increase the number of ears per plant of the more prolific genotypes. Genotypes with a greater average ear number were more efficient in using accumulated N in producing grain and partitioned more of the total plant N and DM to grain production.
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