No abstract

Resumo - Palavras-chave -Glycine max (L.). Melhoramento-genético. Interação genótipos-ambientes.Abstract -In order to evaluate the performance of soybean cultivars, three essays were carried out at Formoso do Araguaia, TO,Brazil, in the inter-cropping 2007 (15/05, 30/05 and 12/06). The experimental design employed was a randomized blocks with ten treatments and tree replications. The treatments were composed by ten soybean cultivar (DM Nobre, NIDERA In 7002, DM 247, DM 309, DM 339, M-SOY 8411, M-SOY 8914, M-SOY 8866, M-SOY 9350 and FT 106). In evaluating the performance of cultivars, a study was conducted of adaptability and stability by the methods of Eberhart and Russell (1966) and centroid. The average grain yield varied from 1023 kg ha -1 (15/05) to 1234 kg ha -1 (12/06), with a general average of 1142 kg ha -1 . Based on the classification obtained by the methods of Eberhart and Russell (1966) and centroid, the cultivars DM Nobre, NIDERA In 7002, M-SOY 9350 and M-SOY 8914, were promising for the cultivation under conditions of intercropping. There was agreement among the methods on the classification of genotypes.

A novel yeast species, Metschnikowia cerradonensis sp. nov., is described from 12 strains isolated from flowers of Ipomoea carnea and from beetles of the genus Conotelus in the Cerrado ecosystem in the region of Jalapã o, Tocantins State, Brazil. Analysis of the sequences of the rRNA gene cluster suggested that M. cerradonensis is closely related to Metschnikowia santaceciliae, Metschnikowia continentalis and an undescribed species represented by strain UWOPS 00-154.1. These species mate together but ascospores are very rarely formed, showing that they represent distinct biological species. M. cerradonensis is apparently endemic to the Cerrado ecosystem of the Jalapã o area. The type strain of M. cerradonensis is UFMG 03-T67

Two novel yeast species were isolated from nectar of flower bracts of Heliconia psittacorum (Heliconiaceae) collected in a Cerrado ecosystem in the state of Tocantins, northern Brazil. Wickerhamiella pagnoccae sp. nov., which is closely related to Candida jalapaonensis, is heterothallic and produces one spheroid ascospore per ascus. Candida tocantinsensis sp. nov. belongs to the Metschnikowiaceae clade and its nearest relative is Candida ubatubensis, but the sequence identity (%) in the D1/D2 domains of the rRNA gene is low. The type strain of W. pagnoccae is UFMG-F18C1T ( = CBS 12178T = NRRL Y-48735T) and the type strain of C. tocantinsensis is UFMG-F16D1T ( = CBS 12177T = NRRL Y-48734T).

Probiotic microorganisms (Saccharomyces cerevisiae var. boulardii, S. cerevisiae UFMG 905, and Lactobacillus delbrueckii UFV H2b20) were evaluated as biological control agents to reduce aflatoxin and spore production by Aspergillus parasiticus IMI 242695 in peanut. Suspensions containing the probiotics alone or in combinations were tested by sprinkling on the grains followed by incubation for seven days at 25°C. All probiotic microorganisms, in live and inactivated forms, significantly reduced A. parasiticus sporulation, but the best results were obtained with live cells. The presence of probiotics also altered the color of A. parasiticus colonies but not the spore morphology. Reduction in aflatoxin production of 72.8 and 65.8% was observed for S. boulardii and S. cerevisiae, respectively, when inoculated alone. When inoculated in pairs, all probiotic combinations reduced significantly aflatoxin production, and the best reduction was obtained with S. boulardii plus L. delbrueckii (96.1%) followed by S. boulardii plus S. cerevisiae and L. delbrueckii plus S. cerevisiae (71.1 and 66.7%, resp.). All probiotics remained viable in high numbers on the grains even after 300 days. The results of the present study suggest a different use of probiotics as an alternative treatment to prevent aflatoxin production in peanut grains.

Enophytic fungi were isolated from plum (Prunus domestica) leaves, identified with ITS1 and ITS4 primers, and their antagonistic activity was tested against Monilinia fructicola, which causes brown rot, blossom blight, and twig blight of stone fruits, and Colletotrichum gloeosporioides, which causes anthracnose on a variety of fruit crops. The production of antifungal compounds was determined in agar-diffusion and volatile inverted-plate tests. A total of 163 fungi were recovered from 30 plum trees, representing 22 cultivars. Twenty-nine morphotypes were detected, but only 14 species were identified genetically. The most frequently isolated species was Phaeosphaeria nodorum, constituting 86.5% of the total isolates. Four isolates produced inhibitory volatiles to M. fructicola; however, no isolate produced volatiles inhibitory to C. gloeosporioides. The volatiles produced by these fungi were identified as ethyl acetate, 3-methyl-1-butanol, acetic acid, 2-propyn-1-ol, and 2-propenenitrile. The fungal volatiles inhibited growth and reduced width of the hyphae, and caused disintegration of the hyphal content. This is the first study describing fungal endophytes in stone fruits. The P. nodorum strains producing inhibitory volatiles could play a significant role in reduction of M. fructicola expansion in plum tissues. Potential of these strains for biological control of this pathogen on stone fruits warrants further investigation.

Aflatoxin B(1) is a toxigenic and carcinogenic compound produced by Aspergillus flavus and Aspergillus parasiticus. To inhibit aflatoxin contamination of peanuts, seeds of two peanut breeds, IAC Caiapó and IAC Runner 886, were inoculated with A. parasiticus (1.0 × 10(6) spores per ml) and the yeast Saccharomyces cerevisiae (3.2 × 10(7) cells per ml) and incubated at 25°C for 7 and 15 days. Two experiments were conducted for each incubation period separately. The treatments were completely randomized, with three replications per treatment. Treatments included the two cultivars and three types of inoculation (pathogen alone, yeast and pathogen, and yeast 3 h before pathogen). Aflatoxin B(1) was quantified with a densitometer at 366 nm after thin layer chromatography. Aflatoxin B(1) contamination in peanuts was reduced after the addition of S. cerevisiae. The concentration of aflatoxin B(1) decreased by 74.4 and 55.9% after 7 and 15 days, respectively. The greatest aflatoxin reduction was observed when S. cerevisiae was inoculated 3 h before the pathogen in IAC Caiapó seeds and incubated for 7 days at 25°C. The use of S. cerevisiae is a promising strategy for biological control of aflatoxin contamination in peanuts.

In this study we evaluated the ability of Saccharomycopsis schoenii Nadson and Krassiln (UWO-PS 80-91) as biocontrol agent against plant pathogenic filamentous fungi P. expansum Link (UFMG 01-2002), P. italicum Wehmer (LCP 61.1199), and P. digitatum (Pers.: Fr.) (LCP 984263, LCP 68175 and LCP 4354). S. schoenii was able to reduce disease severity in oranges inoculated with all fungi. Among the phytopathogens, P. digitatum LCP4354 was the most virulent whereas P. digitatum LCP 68175 was the most susceptible to predation. The yeast was able to survive for 21 days on the fruit surface and did not produce lesions on oranges. Production of antagonistic substances by S. schoenii was not detected using standard techniques. Our results point to the potential use of S. schoenii to control postharvest phytopathogens in fruits.