Harvest Index Maize
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Projekt title: |
Increase of maize harvest index to improve water und nutrient use efficiency for a more sustainable crop production |
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Duration: |
2018-2021 |
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Funded by: |
Deutsche Forschungsgemeinschaft (DFG), Project number: HU554/5-1 |
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Staff involved: |
Prof. Dr. Birgit Hütsch, Prof. Dr. Sven Schubert |
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The harvest index (HI = grain yield/total aboveground biomass) of many agricultural crops has been strongly increased during the last decades. However, the HI of maize has only marginally increased since the introduction of hybrids, thus improvements in grain yield were combined with the production of a huge, normally unused biomass. However, this requires high amounts of water and nutrients, which could be used more efficiently due to an increase of the HI, allowing a more sustainable production. In future, this will be particularly important as due to climate change water scarcity will be strengthened, and applications of fertilizers have to be reduced to meet environmental limits (e.g. EU fertilizer legislation to reduce nitrate contamination of ground-water). Two ways for improvement of maize HI are suggested: increase in kernel setting and decrease of vegetative shoot biomass. For better kernel setting, the phytohormone indole-acetic-acid (IAA), a member of the auxins, was tested. Although IAA stimulated the plasma membrane (PM) H+-ATPase, no significant improvements of kernel setting have been achieved so far. With application of the gibberellin biosynthesis inhibitor paclobutrazol (PAC) the vegetative shoot biomass of six maize cultivars was strongly reduced, resulting in significant increases of HI and due to significantly less water requirement in an improved water-use efficiency. However, some cultivars showed yield depressions after PAC application, as frequently described in the literature. With adjustment of PAC application time yield depressions could probably be avoided.
Literature Hütsch BW, Schubert S (2017) Review - Harvest index of grain maize: Are there possibilities for improvement? – In: D.L. Sparks, Ed., Adv. Agron. 146C, 37-82. https://doi.org/10.1016/bs.agron.2017.07.004 Hütsch BW, Schubert S (2021) Water-use efficiency of maize may be increased by the plant growth regulator paclobutrazol. - J. Agro. Crop Sci. 207, 521-534. https://doi.org/10.1111/jac.12456 Hütsch BW, Schubert S (2022) Review - Stimulation of plasma membrane H+-ATPase by auxins or fusicoccin and its relation to maize kernel setting, grain yield, and harvest index. – In: D.L. Sparks, Ed., Adv. Agron. 174, 235-267. https://doi.org/10.1016/bs.agron.2022.03.004 |
Figure 1 Effect of the plant growth regulator paclobutrazol (PAC) on (a) the development of six maize varieties (50 days after sowing [DAS] and 18 days after application) and (b) the cobs at maturity (144/145 DAS). PAC dosage per plant: Amanova, Galactus 3 mg a.i.; Severeen, Hubble, Fabregas 2 mg a.i.; Pioneer 1 mg a.i.
Figure 2 Harvest Index (HI) of different maize cultivars after application of the growth regulator Paclobutrazol (PAC). |
