Phosphateffizienz von vier Weizengenotypen (Triticum aestivum L.) des CIMMYT (Mexiko)

Abstract

The main objective of the experiment was to compare the phosphorus efficiency of three CIMMYT bred genotypes of wheat (‘ChilWuh’, ‘BauKauz’, and ‘PgoSeri’) with the old Mexican variety ‘Curinda’. These four strains of wheat genotypes were cultivated in the field (sandy clay, 3.7 ppm Olsen P, in Mexico) at two P levels (0 and 80 kg P₂O₅/ha). All four genotypes responded positively to P fertilization. In comparison with P-0, the yield of P-80 was 78 % higher. The three new genotypes ‘ChilWuh’, ‘BauKauz’, ‘PgoSeri’ showed significantly higher yields when compared with the old variety ‘Curinda’. The yield difference was 54 % at P-0 and 42 % at P-80. The higher yield was mainly due to a larger number of grains per ear, higher thousand grain weight (TGW) as well as a higher harvest index. The old variety ‘Curinda’ was superior with regard to the number of ears per unit area. As a result of this experiment, the new genotypes could be classified as P efficient. This high level of P efficiency is mainly due to a more effective P uptake, however, there was little change with respect to P utilisation between old and new varieties. The P uptake at harvest averaged 35 % and 24 % more as the old variety ‘Curinda’ at P-0 and P-80 respectively. These results show that at P-0 level, the morphology of the root system played a greater role when compared with conditions of higher P fertilization. Due to their higher root length density after flowering, the new varieties showed an improved P uptake even at P-0 fertilization levels, while at P-80, a higher P influx per unit root length played a more important role than root length density.