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NITROGEN: ITS EFFECT ON THE EXPRESSION OF PROLIFICACY AND ITS UTILIZATION BY PROLIFIC AND NON-PROLIFIC GENOTYPES OF MAIZE (ZEA MAYS L.)
Abstract
A field experiment to study effects of nitrogen level on prolificacy (number of ears per main stalk) and its' inheritance was conducted in 1980 and 1981, two contrasting years with respect to rainfall and temperature. Prolific and non-prolific parent lines and derived generations, F1, F2, BC1, and BC2, were used. A greenhouse experiment to study nitrogen uptake and utilization by prolific and non-prolific S(,1) families grown in nutrient solutions was also conducted in the spring and summer, 1981. Additive gene effects accounted for most of the genetic variation in prolificacy among generation means in 1980, but non-additive effects seemed to play a much greater role in 1981 than in 1980. Heterosis from dominance or epistasis effects were noticeable in crosses involving OH 43 as the non-prolific parent in 1981. Gene effect x nitrogen level interactions were generally absent, suggesting consistent performances at all levels of nitrogen. However, gene effect x year interactions were significant indicating that gene control is not consistent over different environments. Under stress conditions, heterosis failed to be expressed, but when rainfall and temperatures were favorable, expression was evident. If overdominance is involved or if dominance types of epistasis are involved in the heterosis observed, some system of interpopulation selection will be necessary to utilize such variation. The results from the greenhouse study showed that, (1) prolific genotypes extracted more nitrogen from nutrient solutions, than non-prolific genotypes, and (2) differences in nitrogen uptake were in the nitrate fraction, not the ammonium fraction. Prolific S(,1) families used in the greenhouse experiment produced more ears and higher yields in the field. These results suggest that prolific genotypes are more efficient than non-prolific ones in use of nitrogen. To increase nitrogen uptake efficiency, breeders need to have some measures of nitrogen uptake in their selection criterion.
Subject Area
Agronomy
Recommended Citation
CASNOFF, DAVID MICHAEL, "NITROGEN: ITS EFFECT ON THE EXPRESSION OF PROLIFICACY AND ITS UTILIZATION BY PROLIFIC AND NON-PROLIFIC GENOTYPES OF MAIZE (ZEA MAYS L.)" (1983). ETD collection for University of Nebraska-Lincoln. AAI8401385.
https://digitalcommons.unl.edu/dissertations/AAI8401385