Comparing the effects of grain weathering and presence of fungal communities on waxy and non-waxy sorghum hybrids grown across texas

Authors: KENT, MITCHELL - Texas A&M University; Prom, Louis; ROONEY, WILLIAM - Texas A&M University

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/25/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: Grain weathering or grain mold, caused by many species of fungi, is an important disease of sorghum and yield losses of up to 100% can occur when susceptible lines are planted. In this study, the effects of weathering and fungi on sorghum lines with waxy endosperm which are more digestible but said to be susceptible to grain weathering were compared with non-waxy lines. The results showed that many fungal species are present on the grain and that lines with waxy endosperm are no more susceptible to grain weathering than lines with non-waxy endosperm. This work is significant because it suggests that lines with waxy endosperm that are more digestible for animal feed and human food can have levels of grain weathering and grain mold tolerance that are acceptable for commercial grain production.

Technical Abstract: Grain weathering in grain sorghum is a persistent concern for producers in warm and humid climates. Further, rain sorghum genotypes are known to vary in their response to grain weathering; in some cases, this response is associated with a specific grain trait. For example, waxy endosperm sorghum is perceived to be more susceptible to grain weathering. This study herein compared a set of waxy, heterozygous waxy and non-waxy sorghum hybrids grown in multiple environments for grain weathering susceptibility and characterization of the fungal communities on the grain. The traits used to evaluate grain weathering and grain mold included grain weathering rating (FGWR), area under the disease progress curve (AUDPC), initial germination (IG) and reduction in germination (RIG). Grain weathering intensity varied among the tested environments; increased weathering occurred with wetter conditions. In combined analyses, the environment accounted for more variation (70.2%, 38.2%, 39.9% and 81.1%) than did genotype (9.0%, 26.9%, 15.8% and 5.0%) for FGWR, AUDPC, IG and RIG, respectively. In only one of the four environments were the waxy and heterozygous waxy hybrids statistically different from the non-waxy genotypes. Ultimately, variation was more associated with genotypes than endosperm classes. Overall, Alternaria spp., Biploris spp., Fusarium semitectum, Curvularia app. and Aspergillus niger were the most frequently observed pathogens across environments. Within an environment, the frequency of different fungal pathogens remained relatively constant, but they varied across different environments without any clear distinction among the level of grain weathering, a particular pathogen, and endosperm type. The results indicate that waxy endosperm is no more susceptible to grain weathering than normal endosperm grain sorghums.