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Forage sorghum presents tall plants, what makes mechanical seed harvesting a difficult task. Plant hormones can reduce plant height and facilitate the harvesting. Thus, the objective of this study was to evaluate the effect of the growth regulator trinexapac-ethyl on plant height and seed yield in forage sorghum. This research was carried out at Embrapa Maize and Sorghum, in two seasons (2017 and 2018), in a randomized complete block design, four replications and three varieties (BRS Ponta Negra, 1141574 and 0947216) under application of Trinexapac-ethyl in two stages of the plant growth (V8, V12, V8 + V12). The characteristics evaluated were: plant height, seed yield and mass of 1000 seeds. The effect of the hormone was significant in both stages of growth, with a significant reduction in plant height. The hormone applied twice at growth stages V8 + V12 had a greater effect in reducing plant height. However, the hormone reduced seed yield in the three varieties, what implies the need for further studies comparing the advantage of plant height reduction and the loss in seed yield. Made available in DSpace on 2021-10-27T13:00:27Z (GMT). No. of bitstreams: 1 Trinexapac-ethyl-reduces.pdf: 493049 bytes, checksum: 42bff85016ca6a8a2608bce5b50fbd45 (MD5) Previous issue date: 2021

The objective of this study was to estimate the adaptability and stability of grain sorghum hybrids grown under post-flowering water stress and non-stress conditions. The trials were carried out in Nova Porteirinha-MG during the season of 2014 and 2015, and in Teresina-PI in the 2014 season. Twenty-nine-grain sorghum hybrids were evaluated, in a randomized complete block design, with three replications. Plots consisted of four lines with 3 m long. The grain yield data were submitted to the individual variance analysis, having considered the effects of the hybrids as fixed and the other effects as random. The joint analysis was carried out, and when the interaction genotypes x environments was significant, the grain yield data were submitted to the adaptability and stability analysis by the GGE biplot method. A substantial reduction in the grain yield in environments with water stress was found. The highest yielding hybrids under water stress conditions in Nova Porteirinha-MG were 50A50, AG1080, AG1090, DKB550, DKB590, Jade, and BM737, and the highest yielding hybrids under the water stress in Teresina-PI were 1G282, 1G244, and A9721R. Considering all environments, the highest yielding hybrids were 1G282, DKB540, A9721R, 1G100, and AG1090. Made available in DSpace on 2017-09-23T00:13:45Z (GMT). No. of bitstreams: 1 Performancegrain.pdf: 1041239 bytes, checksum: 8ccfa98437ab622e9f993a05fe203971 (MD5) Previous issue date: 2017-09-21

Sorghum grain yield can be significantly affected by climatic changes, especially drought and high temperature. The purpose of this study was to evaluate hybrids of grain sorghum grown under normal irrigation conditions or water stress in order to select those likely to be more tolerant of drought. Forty-nine hybrids were grown in a randomized block design experiment, with three replications. The plots consisted of four rows of 5 m length. Grain yield, weight of 1000 grains, harvest index, days to flowering, and plant height were measured. All of these characteristics were affected by water stress; however, grain yield showed the largest relative reduction. Comparison of the various genotypes showed that some hybrids had an acceptable grain yield under water stress, and maintained a high average yield compared to growth without stress. Several hybrids gave better grain yield than commercial check cultivars: 1170090, 1170092, 1170064, 1167026, 1167064, 1170093, 1167008, 1167029, 0009061, 1167092, 1105647, and 1170019 stood out for their acceptable plant height, earliness, and higher productivity.