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In natural ecosystems, many plants engage in symbiotic interactions with fungal endophytes which can have impacts on host plant communities. In South American grasslands, several endophytes have been isolated from different Paspalum species. The aim of this work was to evaluate the antagonistic effect of endophytes Trichoderma amazonicum and Acremonium strictum against Claviceps paspali through in vitro and in vivo assays. In addition, they were evaluated as biocontrol agents against fungal pathogens which produce leaf spots such as Alternaria alternata and Bipolaris sp. through in vitro experiments. The in vitro assessment was conducted by dual culture between the antagonists and the three pathogens. For the in vivo assay, plants of Paspalum notatum and Paspalum dilatatum were planted in the field in a completely randomized block design with six replications. Three treatments were applied: T1 = endophyte inoculum, T2 = fungicide, and T3 = control. Seed yield, seed set, healthy seed set, and weight of healthy seed set per kilogram of seeds were evaluated for three timepoints. Trichoderma amazonicum exhibited a high growth inhibition, while A. strictum a moderate to low effect in vitro. In the in vivo assay, significant differences were observed among treatments in both species. T1 increased the kilogram of healthy seed set per 100 kg of seed by increasing the seed set and weight of healthy seed set in at least one of the evaluated dates in P. notatum and P. dilatatum. Based on these results, T. amazonicum and A. strictum have antagonistic effects on the pathogens assessed. Core Ideas: Fungal endophyte Trichoderma amazonicum could be used to increase seed yield in Paspalum notatum.Fungal endophyte Acremonium strictum could be used to increase seed yield in Paspalum dilatatum.Trichoderma amazonicum and Acremonium strictum have the potential to be used as biocontrol agents for frequent grass diseases. [ABSTRACT FROM AUTHOR]

Removal of lettuce basal leaves is a technique used by the seed industry; however, the effects on seed production and physiological potential are unknown. Genetic dissimilarity is fundamental in the identification of individuals in terms of traits of interest, although it is rarely considered in relation to seeds that are tolerant to thermoinhibition. The aim of this study was to ascertain the relationship between defoliation of lettuce plants and seed yield/physiological quality, as well as the genetic dissimilarity among genotypes with regard to seed thermoinhibition. We used 35 lines of biofortified lettuce, the cultivars Uberlândia 10000, Belíssima, UFU MC BIOFORT1, and Everglades (tolerant to thermoinhibition), and Grand Rapids and Verônica (susceptible to thermoinhibition). The seed yield and physiological quality of the genotypes with and without defoliation were evaluated, artificially aged, and germinated at four temperatures in a factorial arrangement. The genetic dissimilarity was estimated by Tocher graphing and the UPGMA clustering method, based on the Mahalanobis generalized distance (D 2 ii). Four UFU genotypes and Grand Rapids had high seed yields. With removal of basal leaves, there was higher seed yield per plant and there was an effect on their physiological quality. The genotypes exhibited genetic variability for thermoinhibition, with UFU-86#2#1#1 and Everglades showing similar performance. [ABSTRACT FROM AUTHOR]

Copyright of Scientia Agraria Paranaensis is the property of Revista Scientia Agraria Paranaensis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Scientia Agraria Paranaensis is the property of Revista Scientia Agraria Paranaensis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Urochloa (syn. Brachiaria) cultivars are widely used as forage for ruminants in tropical countries and also in Thailand. Two new Urochloa cultivars, OKI‐1 and Br‐203, have high forage yield and digestibility compared with other cultivated Urochloa grasses. Seed production is a fundamental requirement for widespread sowing, and it can be increased by optimizing agronomic practices, such as changing plant spacing. Two field trials were conducted in 2018–2020 at Lampang Animal Nutrition Research and Development Center, Northern Thailand, to determine the optimal plant spacing for seed production of these Urochloa cultivars. In both trials, four plant‐spacing regimes (50 × 100, 75 × 100, 100 × 100 and 125 × 100 cm) were used in a randomized complete block design with four replicates. In two consecutive harvests of both trials, plant spacing did not significantly affect seed yield and quality but affected tiller and inflorescence densities. Specifically, significant higher numbers of tillers and inflorescences were produced per unit area at the narrowest plant spacing (i.e., 50 × 100 cm). OKI‐1 and Br‐203 tended to have higher pure seed yields (PSY) at plant spacings of 100 × 100 (136.46 kg/ha) and 75 × 100 cm (79.59 kg/ha), respectively. Both cultivars showed similar trends in PSY, filled seed percentage and a thousand seed weight, which tended to be higher in the first‐year crops than the second‐year crops. This difference could be attributed to a reduction in available soil N resulting from a large amount of N utilization during vegetative growth, combined with inadequate and erratic rainfall. In addition to the recommended optimum plant spacing, sufficient fertilizer and suitable environmental factors could increase seed yield. [ABSTRACT FROM AUTHOR]