Water‐use efficiency of maize may be increased by the plant growth regulator paclobutrazol

Abstract

The increase in agricultural production during the 1930s to late 1960s ('green revolution') was mainly brought about by the introduction of semi-dwarf varieties of wheat and rice combined with the introduction of chemical fertilizers and pesticides. The dwarfing genes are involved in gibberellin (GA) biosynthesis and me-

Can nutrient‐utilization efficiency be improved by reduced fertilizer supply to maize plants treated with the plant growth regulator paclobutrazol?

“…In these studies, all plants received the same amount of fertilizers, although the growth of the PAC‐treated plants was strongly reduced. These smaller plants showed luxurious nutrient consumption resulting in highly significant increases in N concentrations of grain and straw, and in P and K concentrations of straw compared with the untreated control (Hütsch & Schubert, 2021). Thus, with adjusted fertilizer supply according to the lower requirement of PAC‐treated plants, luxurious consumption can probably be avoided and improvements of nutrient‐utilization efficiencies may be expected.…”

“…In order to decrease vegetative shoot growth of maize, the gibberellin‐biosynthesis inhibitors paclobutrazol (PAC) and uniconazole (UCZ) are suitable. PAC‐ and UCZ‐treated maize plants showed decreased plant height and thicker culms due to reduced elongation growth of the internodes (e.g., Hütsch & Schubert, 2018, 2021; Iremiren et al., 1997; Kamran et al., 2018; Schluttenhofer et al., 2011).…”

“…For several maize cultivars, an improvement of the harvest index was obtained by PAC application (Hütsch & Schubert, 2018, 2021). Concomitantly, an increase in water‐use efficiency for the time around silking was achieved.…”

“…This time span is particularly important for kernel setting, as water limitation during flowering can cause kernel abortion making an efficient water use decisive to achieve high grain yields. However, no increases in nutrient‐utilization efficiencies were observed after PAC application to maize plants (Hütsch & Schubert, 2018, 2021). Instead, among six tested cultivars, significant decreases in nutrient‐utilization efficiencies occurred for N and K in five and three cultivars, respectively, and no effect for P was recorded due to PAC application in comparison with untreated control plants (Hütsch & Schubert, 2021).…”

“…However, no increases in nutrient‐utilization efficiencies were observed after PAC application to maize plants (Hütsch & Schubert, 2018, 2021). Instead, among six tested cultivars, significant decreases in nutrient‐utilization efficiencies occurred for N and K in five and three cultivars, respectively, and no effect for P was recorded due to PAC application in comparison with untreated control plants (Hütsch & Schubert, 2021). In these studies, all plants received the same amount of fertilizers, although the growth of the PAC‐treated plants was strongly reduced.…”