Genetic improvement of soybeans in Brazil: South and Midwest regions

Abstract: Soybean [Glycine max (L.) Merril] is one of the main crops produced worldwide, and on-farm yields have increased considerably in the last decades in Brazil. We evaluated the genetic gain for agronomic, phenological, and end-use quality traits in 29 cultivars in the South Region, and in 38 cultivars in the Midwest Region in Brazil, released from 1966 to 2011. Field trials were conducted in Macroregions 1, 2, and 4, in 2016?2017, 2017?2018, and 2018?2019 crop seasons. The best linear unbiased predictors (BLUP) of the cultivars were obtained for each trait using a linear model. The BLUPs were regressed with the year of release using linear and quadratic regression models. The rates of genetic gain for seed yield ranged from 11.98 to 15.31 kg ha?1 yr?1 (0.33 to 0.42% yr?1) in the South Region, and from 13.58 to 21.84 kg ha?1 yr?1 (0.47 to 0.77% yr?1) in the Midwest Region. New cultivars presented taller plants and more seed oil content, oil and protein yield, and lower seed weight, days to flowering, days to maturity, and seed protein content than old cultivars in the South Region, although with differences between the Macroregions. In the Midwest Region, new cultivars showed higher seed oil content, oil and protein yield, and lower bottom pod height and seed protein content than old cultivars. Our results showed that breeding programs have been efficient to improve soybean yield and other traits across the years, without yield plateaus in sight

Capacidade de combinação em genótipos de trigo estimada por meio de análise multivariada.

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Infection by Moniliophthora perniciosa reprograms Micro-Tom physiology, establishes a sink and increases secondary cell wall synthesis

Witches’ broom disease of cacao is caused by Moniliophthora perniciosa. By using Micro-Tom (MT) tomato (Solanum lycopersicum) as a model system, we investigated the physiological and metabolic consequences of M. perniciosa infection to determine if symptoms result from sink establishment during infection. Infection of MT caused a reduction in root biomass and fruit yield, while decreasing leaf gas exchange and downregulating photosynthesis-related genes. The total leaf area and water potential decreased, while ABA levels, water conductance/conductivity, and ABA-related gene expression increased. Genes related to sugar metabolism and those involved in secondary cell wall deposition were upregulated upon infection, together with increased levels of sugars, fumarate, and amino acids. 14C-glucose was mobilized towards infected MT stems, but not in inoculated stems of the MT-line overexpressing CYTOKININ OXIDASE-2 (35S::AtCKX2), suggesting a role for cytokinin in establishing the sugar sink. The upregulation of genes involved in cell wall deposition and phenylpropanoid metabolism in infected MT, but not in 35S::AtCKX2 plants, suggests a cytokinin-mediated sink establishment that promotes tissue overgrowth with the increase in lignin. Possibly, M. perniciosa could benefit from the accumulation of secondary cell walls during its saprotrophic phase of infection