Genetic and Pathogenic Variability among Isolates of Causing Sorghum Head Smut.

, the causal agent of sorghum ( (L.) Moench) head smut, is present in most sorghum-producing regions. This seed replacement fungal disease can reduce yield by up to 80% in severely infected fields.

Genome-wide association analysis for response of Senegalese sorghum accessions to Texas isolates of anthracnose.

Anthracnose disease of sorghum is caused by Colletotrichum sublineola, a filamentous fungus. The genetic basis of resistance to anthracnose in sorghum is largely unclear, especially in Senegalese sorghum germplasm. In this study, 163 Senegalese sorghum accessions were evaluated for response to C.

Leaf angle distribution in Johnsongrass, leaf thickness in sorghum and Johnsongrass, and association with response to Colletotrichum sublineola.

Basal leaf angle distribution was surveyed in twenty-one Johnsongrass cultivars near the end of the vegetative stage. The angles increased from the top to the bottom leaves, and compared to cultivated grain sorghums, the average angle was larger in Johnsongrass. When basal leaf angle distribution data were correlated with pathogenicity test data from excised-leaf assays for three isolates of Colletotrichum sublineola, the results showed a weak positive correlation between basal leaf angle and pathogenicity level in Johnsongrass.

A comparison of Bt transgene, hybrid background, water stress, and insect stress effects on corn leaf and ear injury and subsequent yield.

Experimentally manipulated water and insect stresses were applied to field-grown corn with different Bacillus thuringiensis (Bt) transgenes and no Bt transgenes, and different nontransgenic hybrid backgrounds (2011 and 2012, Corpus Christi, TX). Differences in leaf injury, ear injury, and yield were detected among experimental factors and their interactions. Under high and low water stress, injury from noctuid larvae (Lepidoptera: Noctuidae) on leaves during vegetative growth (primarily from fall armyworm, Spodoptera frugiperda J.

Virulence and Molecular Genotyping Studies of Sporisorium reilianum Isolates in Sorghum.

Head smut, caused by the fungal pathogen Sporisorium reilianum, has been reported with increasing frequency in the grain sorghum growing areas of Texas. To facilitate analysis of changes in pathogen virulence, four inoculation techniques were examined: soil and teliospore mixture, seed coating, media placement, and syringe injection. Of the four, syringe injection was determined to be the most effective.

Simple sequence repeat markers useful for sorghum downy mildew (Peronosclerospora sorghi) and related species.

Background: A recent outbreak of sorghum downy mildew in Texas has led to the discovery of both metalaxyl resistance and a new pathotype in the causal organism, Peronosclerospora sorghi. These observations and the difficulty in resolving among phylogenetically related downy mildew pathogens dramatically point out the need for simply scored markers in order to differentiate among isolates and species, and to study the population structure within these obligate oomycetes. Here we present the initial results from the use of a biotin capture method to discover, clone and develop PCR primers that permit the use of simple sequence repeats (microsatellites) to detect differences at the DNA level.

Effects of bacillus thuringiensis transgenic corn on corn earworm and fall armyworm (Lepidoptera: Noctuidae) densities.

We examined 17 pairs of near-isogenic hybrids of Bacillus thuringiensis (Bt) (176, Mon810, and Bt11) and non-Bt corn, Zea mays L., to examine the effects of Bt on larval densities of Helicoverpa zea (Boddie) and Spodoptera frugiperda (J. E.

Decreased whorl and ear damage in nine mon810 Bacillus thuringiensis (Bt)-transgenic corn hybrids compared with their non-Bt counterparts.

We examined nine pairs of near-isogenic hybrids of Bacillus thuringiensis (Bt) and non-Bt corn, Zea mays L., at two locations in 1999 and three locations in 2000 to compare the effects of Bt toxins on damage caused by Helicoverpa zea (Boddie) to whorl stage field corn, and ear damage at harvest, as well as yield. We found that whorl damage was less in all Bt hybrids compared with their non-Bt counterparts each year and at each location.

Survival of Claviceps africana Within Sorghum Panicles at Several Texas Locations.

Survival of the sorghum ergot fungus, Claviceps africana, based on pathogenicity of recovered macroconidia used to inoculate sorghum (Sorghum bicolor), was measured in 2000 over the course of the year at five locations in Texas representing three climates. The experiment was repeated in 2001. Sphacelia associated with infected sorghum panicles were placed in nylon mesh bags and either buried at a 10-cm depth, placed on the soil surface, or suspended 61 cm above the ground.