Michael J. Giroux

Background and Objectives: Durum wheat ( Triticum turgidum L. subsp. durum ) pasta quality depends on grain yellowness, gluten strength, and protein content, and can be modified by altering starch composition. High‐amylose null mutants improve nutritional traits but often reduce seed size, yield, and processing quality. This study evaluated milling performance and pasta properties of durum lines carrying hypomorphic starch synthase IIa (SSIIa)‐B missense mutations that moderately increase amylose. Findings: Double mutant lines ssIIa‐B P333S and ssIIa‐B G330D (each with ssIIa‐A null) increased amylose to 36%–39% versus ~28%–29% in wild‐type and single mutant sister lines, while maintaining protein concentration and kernel size. Total starch and semolina yield were modestly reduced, with a significant yield reduction in ssIIa‐B G330D. Uncooked pasta yellowness decreased by 11.7%–14.4%, whereas cooked pasta color changes were small. Pasta firmness increased across cooking times, accompanied by a slight but significant increase in cooking loss. Conclusions: Moderate amylose increases from SSIIa missense mutations enhance pasta firmness while avoiding the severe agronomic penalties typical of high‐amylose null lines. Significance and Novelty: This work provides the first characterization of milling and pasta properties of durum carrying SSIIa hypomorphic alleles that deliver intermediate amylose levels, revealing a practical route to firmer pasta with modest tradeoffs in yield and color.

The Reduced Height‐1 ( Rht‐1 ) gene in wheat ( Triticum aestivum L.) has been well studied since the introgression of semidwarfing alleles Rht ‐ B1b and Rht ‐ D1b into many wheat varieties in the mid‐20th century. Rht‐B1b and Rht‐D1b increase plant productivity but also reduce single grain weight and protein content. Other alleles of Rht‐1 as well as other height‐affecting genes have been studied to provide breeders with alternative ways to modify plant height. To find Rht‐A1 alleles that could be used to fine tune plant height and other phenotypic traits that are affected by Rht‐1 , an ethyl methanesulfonate mutagenized Alpowa spring wheat population was screened for Rht‐A1 N‐terminal mutations. Nine mutations were identified and characterized through yeast two‐hybrid experiments to measure the impact each mutation had upon interaction with the gibberellin receptor GID1. Near isogenic lines were created by backcrossing the nine alleles into the cultivars Vida and Duclair, both with and without the semidwarfing allele Rht‐B1b , and tested in preliminary spaced‐plant trials. Five of these Rht‐A1 alleles (including a nonsense mutation allele, Rht‐A1 ‐Q6*) were selected for inclusion in full density yield trials. Only one mutant allele, Rht‐A1‐ E63K, consistently decreased height across tested backgrounds. This included a height decrease of 6 cm and a yield increase of 12% in a “tall” background when no other height reducing alleles were present. The Rht‐A1 ‐E63K mutation occurs within the LExLE motif where Rht ‐ B1b and Rht ‐ D1b mutations also occur, emphasizing the importance of this locus to the function of Rht‐1 .

Hydrogen sulfide is a plant gasotransmitter that can increase plant growth. Application of compounds that slowly release hydrogen sulfide (H ₂ S) is emerging as a method to increase plant growth and yield. This study investigated how dibutyl dithiophosphate (DBDTP), which releases H ₂ S when metabolized by a plant, impacts potato growth and development. Two commonly grown potato varieties, Russet Burbank (RB) and Clearwater (CW), were grown under tissue culture, field, and growth chamber conditions with varying amounts of DBDTP. Potato root length was increased in tissue culture when DBDTP was included in the media at 0.025 and 0.1 mM. Potato plant height was also increased, though not significantly, at 0.05 mM DBDTP, while 0.2 mM DBDTP significantly reduced plant height. Under field conditions, potato yield was increased when DBDTP was applied as a 0.5 mM soil drench in 2023. Treated plants yielded 57.9 g per plant, compared to 33.5 g per plant for control plants, with a positive trend detected in 2024. Foliar sprays containing 0.5 mM DBDTP did not cause any visible damage to potato leaves when applied eight days after transplanting in growth chambers. DBDTP was associated with increased auxin pathway gene expression at seven and twelve days after DBDTP treatment. This study demonstrates the versatile ways in which DBDTP may be applied to improve potato growth under tissue culture, growth chamber, and field conditions.

The wheat ( Triticum spp.) Reduced height‐1 ( Rht‐1 ) B1b and D1b semidwarfing alleles have been well studied since their incorporation into modern breeding populations in the 1960s. Useful alternatives to these alleles have been studied in hexaploid wheat ( Triticum aestivum L.), but less so in tetraploid durum wheat ( Triticum turgidum L. subsp. durum ). Most durum varieties are either tall or semidwarf, containing either the Rht‐B1a (tall) or Rht‐B1b (semidwarf) alleles. Because of the dosage‐dependent nature of these alleles, tetraploid semidwarf durum wheat is significantly shorter than hexaploid semidwarf wheat, meaning that in low resource environments, semidwarf durum varieties may yield less and are often too short to be effectively harvested. Thus, the identification of Rht‐1 alleles that confer intermediate height is needed. Near isogenic lines were created to test previously characterized alleles Rht‐B1b ‐E529K, Rht‐A1‐ S50F, and Rht‐A1‐ L358F in field trials to measure grain yield. The Rht‐B1b ‐E529K allele was additionally tested in greenhouse trials to evaluate emergence rates at different planting depths. Rht‐A1‐ S50F and Rht‐A1‐ L358F do slightly affect height but also may reduce yield. Rht‐B1b ‐E529K confers intermediate height, single grain weight, grain protein content, and seedling emergence when compared to lines containing the Rht‐B1a allele or the Rht‐B1b allele. Rht‐B1b ‐E529K also increased grain yield by 8.8% compared to Rht‐B1b in one of the five tested environments. The results show that the Rht‐B1b‐ E529K allele could be useful in regions where drastic decreases in height and reduction in seedling emergence conferred by Rht‐B1b can be detrimental.

Wheat (Triticum spp.) is a hardy, drought‐tolerant crop well suited to harsh environments like the Northern Great Plains. In regions with higher rainfall or irrigation, a densely planted, high‐biomass crop ideotype may be preferable. However, in moisture‐stressed climates with variable weather, crops are planted at a lower density, and lines with increased tillering potential can improve yields. Drought‐tolerant genotypes with higher tillering potential can provide a harvestable crop in poor years while maximizing yields in favorable conditions. Greater tillering potential allows plants to capitalize on timely rainfall. Teosinte Branched‐1 (TB1) is a transcription factor that regulates axillary meristem outgrowth in wheat. This study examines its effects on tillering, mature inflorescence morphology, and their impact on grain yield in durum wheat (Triticum turgidum L. subsp. durum). Reducing TB1 function through nonsense mutations in one homeolog can enhance tillering potential, boosting yield under favorable conditions. TB1 variants were analyzed in near‐isogenic line populations across 3 years and five Montana environments. Lines with mutations in both TB1 homeologs had 20% more productive tillers but reduced grain yields in some environments due to reduced spike size. Genotypes containing only the tb‐B1‐W341* nonsense mutation allele had a grain yield increase of up to 20% in environments with optimal mid‐season rainfall and did not yield significantly lower than the wildtype genotypes in any other environment. Integrating a TB‐B1 nonsense allele into durum wheat breeding programs could be useful to increase productive tillers and yield potential.

Shifts in the environment due to climate change necessitate breeding efforts aimed at adapting wheat to longer, warmer growing seasons. In this study, 21 modern wheat (Triticum aestivum L.) cultivars and 29 landraces were screened for flag leaf starch levels, with the goal of identifying a genetic marker for targeted breeding. The landrace PI 61693 was identified as having exceptionally high flag leaf starch values. Yield trials were carried out in a Berkut × PI 61693 recombinant inbred line (RIL) population and a negative correlation was observed between leaf starch, flowering time, and yield. Genetic mapping identified a Quantitative Trait Loci (QTL) explaining 22–34% variation for leaf starch, flowering time, biomass, and seed yield. The starch synthase TraesCS7D02G117800 (wSsI-1) is located in this region, which possibly accounts for leaf starch variation in this population; also within this QTL is TraesCS7D02G111600 (FT-D1). Sequencing of FT-D1 identified a single base pair deletion in the 3rd exon of the Berkut allele. This indel has recently been shown to significantly impact flowering time and productivity, and likely led to significant variation in flowering date and yield in this population. Here, we illustrate how allelic selection of FT-D1 within breeding programs may aid in adapting wheat to changing environments.

‘MT Blackbeard’ (Reg. no. CV‐1212, PI 703025) and ‘MT Raska’ (Reg. no. CV‐1213, PI 703026) are spring durum wheats ( Triticum turgidum L. ssp. durum ) developed by the Montana Agricultural Experiment Station and released in 2022. MT Blackbeard was bred using a four‐parent cross followed by single seed descent and was selected for high yield under rainfed conditions across Montana, low grain cadmium accumulation, large seed size, high gluten strength, and resistance to the most common races of the stem rust ( Puccinia graminis f. sp. tritici ) and leaf spot pathogens in Montana. MT Raska was also bred using a four‐parent cross followed by single seed descent and was selected for high yield under rainfed conditions across Montana, semi‐dwarf plant height, exceptional test weight, semolina color retention, and resistance to the most common races of the stem rust and leaf spot pathogens in Montana. Both lines yield well in the North Central and Eastern regions of Montana, where most Montana durum is produced and are intended for pasta production. MT Blackbeard is approximately 72.7 cm tall, similar to the commonly produced line ‘ND Riveland’, has signature black awns, and flowers 1 day later than ND Riveland. MT Raska is approximately 56.2‐cm tall, significantly shorter than ND Riveland, and flowers approximately 4 days earlier than ND Riveland.

Wheat (Triticum aestivum L.) has inflorescences made up of multiple spikelets arranged along a central rachis, with each spikelet producing between one and four grains. The Grain Number Increase 1 (GNI‐A1) gene wheat directly influences grain number per spikelet and grain size. Three naturally occurring alleles have been described previously: GNI‐A1‐105N, 105Y, and 105K. This project's goal was to characterize the impact of these alleles within hard red spring wheat cultivars in Montana, where each of the alleles is common. The 105N allele and the 105K allele were compared through analysis of an F₅ Vida by Spring‐Yellowstone recombinant inbred line (RIL) population, and with near isogenic lines (NILs) derived from the same population. The 105N allele and the 105Y allele were compared with NILs derived from an F₄ Lanning by Egan RIL population. We analyzed the impact of each of the three alleles and compared their effects on inflorescence architecture, grain size, grain yield, grain quality, and milling quality under Bozeman, MT, field conditions. Data show that either loss‐of‐function alleles (105Y and 105K) increased grain number per spikelet by 5% when compared to the more functional allele (105N) across all years and environments tested. Overall grain size was not significantly reduced and there was also not a significant increase in overall grain yield.

Background and Objectives: Preharvest sprouting (PHS) is the premature germination of seeds, which is often caused by late‐season rains after seeds reach physiological maturity. PHS negatively impacts grain yield and end‐use quality. Previous studies in spring bread wheat (Triticum aestivum) and durum wheat (Triticum turgidum) have identified that some mutations in the mother of FT and TFL1 gene (MFT) coding sequence decrease seed dormancy and increase wheat PHS.Findings: Here, we report two novel alleles for the MFT‐A and two novel alleles for the MFT‐B1 homologs in spring bread wheat and durum wheat.Conclusions: A haplotype analysis suggests that TaMFT‐3A1b (OQ729929), TaMFT‐3B1b (OQ729932) and TdMFT‐3B1b (OQ729937) increase PHS susceptibility. It is expected that functional copies of MFT promote seed dormancy. Variant analysis of the novel MFT‐A and MFT‐B1 alleles in both spring and durum wheat suggest impairment of protein function, therefore a negative impact on seed dormancy.Significance and Novelty: Previously unassessed durum wheat varieties were examined for PHS susceptibility. The information in this study can serve as a resource for spring and durum wheat breeders to make selections for alleles of MFT that impact susceptibility to PHS.