Accumulation of Biomass and Nitrogen During Plant Growth in Highly Diverging Genotypes of Winter Wheat

Abstract

Data are presented on the accumulation of nitrogen and total biomass into wheat plants at different stages in their ontogeny. Five genotypes of highly diverging origin and with widely deviating grain protein contents were cultivated at different nitrogen regimes (ranging between 0 and 150 kg N ha‐1). Growth curves as polynomials were calculated from representative subsamples of plant material collected from each plot at weekly intervals, commencing early in the vegetative stage and ending at complete maturity. Dry weights and nitrogen contents were determined for above‐ground plant parts and for grains, when present, and were expressed per nr ground area. During the first 2 years total green areas were estimated as well and leaf area indices (LAIs) calculated and fitted to polynomials. The results from these trials revealed that the two American high‐protein genotypes Goertzen 5559 and Frontiersman produced distinctly less biomass (mainly carbohydrates) than the Swedish genotypes Folke, Solid, and Lantvete during the later phases of growth. The lower biomass production of the American types after anthesis appeared to be more due to a decreased photosynthetic activity and less to a decrease in green area. It was also found that the American genotypes had a higher efficiency in remobilizing previously produced and stored assimilates than the modern Swedish cultivars Folke and Solid, which were more dependent on current photosynthesis. With respect to uptake of nitrogen into biomass there was very little variation between the genotypes at the early stages of plant life, but later on clear differences developed between the American and Swedish genotypes. Thus the former accumulated considerably less nitrogen than the latter, but since the differences between the two groups were still more pronounced regarding accumulation of biomass the American types exhibited higher concentrations of nitrogen in total biomass towards the end of the growing season. This higher concentration of N seems to indicate an increased relative ability for the American types to take up nitrogen from the soil during the grain filling phase but it is uncertain whether a causal relationship actually exists with the ability to accumulate protein in the grains. Estimates of the efficiency to redistribute nitrogen to the grain did not show any significant differences between the five genotypes and the most probable explanation for the high grain protein values of the American genotypes therefore seems to be their relatively low production of carbohydrates (and biomass). In a subsequent paper results horn a comprehensive field trial concerning grain and straw yields, structural yield components, soil analyses, etc. will be presented which further corroborate these conclusions.

Yields of Dry Matter and Nitrogen in Highly Diverging Genotypes of Winter Wheat in Relation to N‐uptake and N‐utilization

“…The efficiency to produce dry matter in relation to the amount of absorbed nitrogen was distinctly lower in the high-protein genotypes Goertzen 5559 and Frontiersman than in the genotypes with normal GPG (Table 5). According to the results presented in the previous communication (BERTHOLDSSON and STOY 1995) only small differences in dry matter production could be found between the genotypes before anthesis but very significant ones dunng the grain filling period. Nitrogen present in above-ground parts was thus not utilized for grain dry matter production to the same extent in the high-protein genotypes as in the types with normal GPG.…”

“…It may also be noticed that Goertzen 3539 and Frontiersman boch exhibited very high numbers of ears per m" but that this trait was counteracted by low numbers of grain per ear to such an extent that the resulting numbers of grains per m^ turned out to be distinctly lower than those of the two best Swedish genotypes. Since numbers of grains per ear as well as 1000-grain weights are determined late in the course of ontogenetic development, the relatively low production of photoassimilates around and after anthesis in Goertzen 5559 and Frontiersman, described in the previous communication (BERTHOLDSSON and STOY 1995), appears to be a major reason for the low values of these parameters and hence also of grain yield.…”

“…The same five wheat genotypes, Goertzen 5559, Frontiersman, Folke, Solid, and Lantvete (from Ultuna) were used as in the previously reported investigations (BERTHOLDSSON and STOY 1995). The plant material was cultured in the 1987-88 season in a field near Svalov and was either included into the above-mentioned plant growth experiments (for determination of yield components) or was raised in special yield plots adjacent to the plant growth plots.…”

Spring Cereals: From Dynamic Ideotypes to Cultivars in Northern Latitudes

“…However, it is less clear whether modern cultivars perform better in limited N conditions. Bertholdsson and Stoy (1995a) and Foulkes et al (1998) found that the most recent cultivars were adapted to higher levels of N and took up relatively more N from fertilizer, whereas the older cultivars had a relatively large uptake of N mineralized from soil. Early vigorous growth has also been suggested as a major factor influencing N uptake in modern wheat lines (Liao et al 2006).…”

Cultivar improvement and environmental variability in yield removed nitrogen of spring cereals and rapeseed in northern growing conditions according to a long-term dataset

“…Results from additional analyses indicated that improvements were consistent and significant over time (Table 8), demonstrating the important role of plant breeding and cultivar selection in improving the balance between applied and harvested N, thereby reducing the N leaching risk. Bertholdsson and Stoy (1995) and Foulkes et al (1998) also reported that the most recent cultivars were adapted to higher fertilizer application N rates and they took up relatively more N from fertilizer compared with older cultivars. Improved yields were associated with genetic improvements in YRN and N 2009b).…”