Componentes ecofisiológicos y numéricos del rendimiento de trigo que explican el incremento de rendimiento del período 2003-2023

Considering the expected increase in the global population over the coming decades, it is estimated that the demand for food will also rise in the future, with wheat being one of the primary sources of energy and protein. However, given the finite nature of resources, genetic improvement emerges as the most viable alternative to meet this growing demand.

The variability quantified in genetic progress reported by different authors introduces some uncertainty regarding how this challenge will be overcome in the future. Therefore, it is necessary to generate local information that contributes to understanding the evolution and determining factors of wheat yield.

This study aimed to analyze the evolution of yield and its main numerical and ecophysiological components, as well as to identify potential interactions and limiting factors. For this purpose, a database from the Wheat Cultivar Characterization Program at EEMAC covering the period 2003-2023 was analyzed.

The cultivars ranked in the top third of annual yield were selected and compared with two long-term reference cultivars (INIA Tijereta and INIA Churrinche) to identify the components explaining yield differences between modern and older cultivars.

The results indicate that modern cultivars exhibited a yield increase rate of 86 kg ha⁻¹ year⁻¹ (1,37% year⁻¹) (p-value: 0,0735), progressing from values close to 6000 kg ha⁻¹ to approximately 8000 kg ha⁻¹ at the end of the study period, with a yield gap of 1,700 kg ha⁻¹ between the two groups.

The numerical yield component that most significantly contributed to the yield increase was grain number (grains m⁻²), which aligns with findings from the majority of authors worldwide. In this regard, modern cultivars differed from the reference cultivars at a rate of 207 grains m⁻² year⁻¹, while grain weight (mg) remained unchanged.

Regarding ecophysiological components, an increase in biomass production was recorded, accompanied by a decline in the harvest index. Based on these results, it can be interpreted that modern cultivars exhibit lower agronomic efficiency due to an imbalance in the ratio of total biomass at harvest to grain yield.

Therefore, in the future, it will be necessary to enhance crop sink capacity, allowing better utilization of the high biomass production that is currently being underutilized.