Genetic progress of malting barley potential grain yield between 1982 and 2019 in Argentina

Abstract

Context: Barley (Hordeum vulgare L.) is one of the most important small grain crops worldwide as well as in Argentina, being this country the main Latin American exporter of barley malt. Genetic progress in potential grain yield is an alternative to increase productivity per unit area and respond to the global demand for food and industry requirements. Understanding the main factors that modify grain yield gain in barley is essential for the effective prioritization of research. However, there are no recent studies evaluating the genetic progress in barley varieties released in Argentina. Objective: Update the data on genetic progress in malting barley cultivars released in Argentina during the last 40 years, characterizing different traits that determine potential grain yield. Methods: Eleven two-rowed commercial malting barley cultivars released in Argentina between 1982 and 2019 were evaluated in a side-by-side field experiment at the School of Agriculture of the University of Buenos Aires during 2020 and 2021 seasons under non-restrictive water, nutrients, and biotic growing conditions. Results: Considering both experimental years, the genetic progress in potential grain yield (in dry matter) of malting barley during the last 40 years was in average 6.86 g m-2 year-1 (0.85% year-1), interacting with the year evaluated. Crop cycle duration in days was increased with the year of release of the cultivars, due to an extension of time to anthesis of 0.18 days year-1 (0.23% year-1) in 2020 and 0.11 days year-1 (0.12% year-1) in 2021. Above-ground biomass at maturity increased with the year of release of the cultivars, at a rate of 6.4 g m-2 year-1 (0.4% year-1), while plant height was reduced by 0.22 cm year-1 (0.30% year-1). Grain yield progress was explained by positive changes in grain number and grain weight. The main driver of changes in grain number per unit area was grain number per spike, as no association was found between spike number and the year of release of the cultivars. Implications: Barley genetic improvement in Argentina successfully increased grain yield potential during the last 40 years. However, our data suggest that the grain yield progress was lower than that required to satisfy the future demand. It is imperative to draw attention to this point to continue increasing barley production per unit area.