Wednesday, February 19^th, 2025

Agronomy 3140, 3:00 – 4:00 pm

“Combining ability of newly developed stay-green sorghum inbred lines.”

Nate Bowser,

Seminar Description: Sorghum [Sorghum bicolor (L) Moench], a crop grown in arid and semi-arid environments, can be enhanced with the stay-green trait to improve post-flowering drought tolerance. Previous studies on stay-green sorghum hybrids have noted a positive association between stay-green and grain yield in low potential environments but did not assess the combining ability or heterotic responses of individual genotypes. In this study, stay-green seed parents developed at Purdue University were crossed with three elite pollinators, and their combining ability and heterotic responses were assessed in multiple locations which represented both stress and non-stress environments. Results showed greater variation in general and specific combining ability estimates in stress environments compared to non-stress environments, with a higher proportion of additive genetic variance compared to non-additive variance in both types of environments. Levels of heterosis for grain yield, 1000 seed weight, and plant height varied across locations and between R-lines. Several experimental hybrids derived from the stay-green inbred lines outyielded commercial hybrid checks in the Ethiopian environments while showing good hybrid seed production potential, with high seed parent yield and good nicking.

Nate Bowser is a first year Plant Breeding PhD student with Dr. Jianming Yu. He graduated from Purdue University with his B.S. and M.S. in Plant Breeding in 2021 and 2024, respectively. During his master’s, Nate evaluated the combining ability and heterotic responses of drought tolerant sorghum inbred lines in high potential and low potential environments. 

“Mapping the secondary structure of a citrus tristeza virus long-noncoding RNA.”

Arianna Kruse,

Seminar Description: Citrus tristeza virus (CTV) is the most destructive viral pathogen in citrus. In the United States, CTV has caused epidemics in both Florida and California and resulted in significant economic losses. During infection, CTV produces a number of sub-genomic RNAs which are involved in protein production and modulation of host immunity. Among these sgRNAs, LMT1, is of particular interest since it's produced abundantly and early in virus infection, yet its function is relatively unknown. This study aimed to map the secondary structure of LMT1 from two different CTV strains through in vitro chemical probing and mutational analysis, identifying key regions of interest for future studies on the strain-specific interactions between CTV variants.

Authors: Arianna Spellman-Kruse, Jodi Bubenik, Tathiana Ferreira Sa Antunes, Maurice S. Swanson, Svetlana Y. Folimonova 

Arianna Kruse completed her bachelor's degree in Biochemistry at the University of Nebraska-Lincoln where she fell in love with the plant sciences. In 2020, she began her PhD in Plant Pathology under Dr. Svetlana Folimonova studying the structure and function of LMT1, a long-noncoding RNA produced by citrus tristeza virus. This year she joined Dr. Jamie O'Rourke's lab here at Iowa State to study abiotic stress tolerance in soybean.