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Abstract The objective of this work was to simultaneously select pre-commercial grain sorghum hybrids with high adaptability and yield stability, through mixed modeling, in 20 environments, during six years. The evaluated plant material consisted of 57 commercial grain sorghum hybrids. In all experiments, hybrids were arranged in a triple lattice design; some experiments used a 6x6 lattice, and others, a 5x5 lattice. Adaptability and stability parameters were obtained based on the prediction by harmonic mean of the relative performance of genotypic values (HMRPGV). The mixed models proved to be adequate to analyze the genotype x environment (GxE) interaction and the genotypic adaptability and stability studies on grain sorghum. The hybrids that stand out, considering all environments are 1G282, A9904, 50A50, A9902, and XB6022. The A9904 hybrid stands out in favorable environments, with a grain yield above average. Only 1G282 is among the five best hybrids for each group of environments, and it is the best grain sorghum hybrid for yield performance, adaptability, and stability. The predicted genotypic values based on genotypic means can be used in the environments with the same GxE interaction pattern because they are free of the GxE interaction.

The presence of aluminum (Al3+) in acidic soils is one of the main causes of low crop yield, since it inhibits the root growth, thus affecting the nutrients and water uptake by plants. An approach to grow crops in areas with high Al3+ saturation is the use of tolerant cultivars. This study aimed to evaluate commercial sorghum hybrids in soils with low and high aluminum saturation, in order to select cultivars with high grain yield, even when exposed to abiotic stress. Twenty hybrids were evaluated for characteristics such as plant flowering, plant height and grain yield. All three traits were significantly affected by Al3+, being grain yield the most affected one. Despite the significant genotypes x environments interaction for grain yield, it was possible to select hybrids with yield above the national average in both environments. The hybrids BRS373, 50A50, AS4639, DKB540, AS4625, A9721R, 1167092, DKB550, 1G282 and AG1040 showed a high yield under low and high Al-saturation conditions.

Sorghum (Sorghum bicolor L. Moench) is one of the most important cereal crops in the world. In Brazil, the acreage of grain sorghum during off-season is quite expansive. Most of this area is the Cerrado, a Brazilian biome that is similar to a Savannah and is characterized by high acidity and soluble aluminum at toxic levels for plants. The aluminum acts as a limiting factor in achieving high yields. The purpose of this work was to phenotype sorghum hybrids for aluminum tolerance. Eighteen hybrids were evaluated in a nutrient solution containing {0} or {27} µM Al3+. The work was carried out in a growth chamber at the Embrapa Maize and Sorghum, from April 4 to May 30, 2014. The lines ATF 13B (susceptible) and ATF 14B (tolerant) were used as check cultivars. Based on the Net Root Growth after 120 hours (NRG120), Net Root Growth (NRG168) after 168 hours and Relative Net Root Growth after 168 hours (RNRG168), it was possible to distinguish tolerant hybrids from susceptible ones. The high aluminum saturation reduced root growth by 70%. The hybrids BRS 310 and BRS 373 were tolerant to aluminum stress under nutrient solution. The hybrid BRS 330 was clustered in an intermediate group, with an approximately 50% root growth reduction. The other hybrids were susceptible with significant root reduction.

In Brazil, grain sorghum has been mainly grown in Cerrado biome during the off‐season, as a succession crop, after the soybean harvest. At this period, rainfall is erratic and insufficient, causing drought stress in pre‐ or post‐flowering of grain sorghum crops. In this scenario, the identification of both drought‐tolerant and irrigation responsive hybrids has been one of the main targets of sorghum breeding programmes. The hypothesis of this research was that grain sorghum genotypes respond differently to different moments of water deficit. This study aimed to evaluate the agronomic performance of sorghum hybrids under full irrigation and drought stress at pre‐ and post‐flowering, in order to identify hybrids tolerant to drought stress and responsive to the water supply. Field trials were carried out in Nova Porteirinha during the 2017/2018 and 2018/2019 crop seasons. Twelve grain sorghum single‐hybrids were evaluated for days to flowering and grain yield in three water availability conditions: drought stress at pre‐flowering, drought stress at post‐flowering and full‐irrigation (control). Tolerant hybrids were identified under both pre‐ and post‐flowering drought stress, as well as hybrids responsive to irrigation. The hybrids 1G282 and 116,748 stood out in the 2017/18 season for high yield and earliness under both drought‐stress conditions, while the hybrid 1G282, AG1090, AS4625 and DKB590 stood out for the 2018/19 season in both stress condition. The hybrid A9904 and 1G282 stood out for its responsiveness to water supply, being recommended to high‐tech farming systems that employ irrigation or for in‐season cultivation. [ABSTRACT FROM AUTHOR]