Genetic progress in cotton dry matter partitioning in Argentina

The Argentinian cotton (Gossypium hirsutum L.) has exhibited a rate of genetic progress of 3.24 kg ha⁻¹ y⁻¹, resulting in an increase of 194.4 kg ha⁻¹ of lint from 1965 to the present day. This improvement has been achieved alongside enhanced seed oil content without compromising lint quality. While previous studies have explored trends in cotton lint yield, lint quality, and other agronomic traits over time, no research in Argentina have focused specifically on genetic progress concerning aboveground biomass, morphological attributes, and mapping-related variables. This study aimed to: i) quantify and compare the levels of aboveground biomass, morphological and mapping-related variables in varieties utilized over the past 50 years in Argentina, and ii) estimate the genetic progress in these variables. Over a two-year period, 20 cotton cultivars were assessed across four different environments through different sowing dates. Several parameters were evaluated, including 11 biomass-related variables, six morphological-related factors, and six mapping-related traits at three different moment of cotton cycle: 50 (M1), 100 (M2), and 150 (M3) days after emergence Significant differences were observed across genotypes, environments, and their interactions. Our findings revealed that variables such as leaf biomass (M2), reproductive branch biomass (M2, M3), first reproductive branch node (M1, M2), first reproductive branch height (M1, M2, M3), and global retention (M2) exhibited either increases or decreases on the rate of genetic progress. This study presents the first report on aboveground biomass values, morphological variables, and mapping-related parameters for Argentinian cotton. The information obtained from the work provides valuable insights into the dynamics of cotton biomass and related variables, contributing to the understanding of genetic improvement in Argentinian cotton cultivation.