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Multi-environment evaluation of winter pea genotypes for winter survival and yield stability
(Montana State University - Bozeman, College of Agriculture, 2024) Poudel, Amrit; Chairperson, Graduate Committee: Kevin McPhee; This is a manuscript style paper that includes co-authored chapters.
Winter pea can be grown as a rotational crop for soil moisture conservation and nutrient recycling in the wheat-growing region of Montana. Development of winter hardy cultivars would increase seed yield and expand the area of adaptation of this crop. Harsh winter conditions present a significant challenge to the production of winter peas. The objective of this study was to screen pea germplasm and breeding lines for winter survival and identify genotypes with good winter hardiness for future crop production. Field trials were conducted to evaluate genotypes at Bozeman, Havre, Huntley, and Moccasin, MT in 2021, 2022, and 2023. These lines included elite winter cultivars and several checks. Winter hardiness was evaluated as the percentage of surviving plants and by agronomic performance including yield. Genotypes were evaluated based on the GGE biplot method. This analysis captured multiple variables including yield, protein content, seed size, and their overall stability across multiple years and locations of study to aid in selecting lines. Differential winter survival was observed across locations and years. Higher winter survival was seen in Bozeman and Havre. Few lines were identified as having high seed yield and stable production over years and locations. Breeding lines had higher mean yield with few good lines having stable production of greater than 2500 kg/ha. Germplasm lines showed better winter survival than breeding lines. Protein content ranged from 20% to 31%. Larger seeds were observed in Moccasin, whereas Havre had the highest protein content. Mega- environment differentiation helped to select specific genotypes based on the trait of interest for a particular environment. Several European and US lines used in the experiments having high winter hardiness record performed better for seed yield and resistance to stress. The lines identified as having high levels of cold tolerance can be used as a prospective genetic resource in pea breeding programs. Genotypes having high and stable seed yield can be considered for release as a variety and made available to producers.
Precision organic agriculture
(Montana State University - Bozeman, College of Agriculture, 2023) Loewen, Royden Alexander Sasha; Chairperson, Graduate Committee: Bruce D. Maxwell; This is a manuscript style paper that includes co-authored chapters.
Organic agriculture addresses some of the shortcomings of industrialized conventional agriculture, but is prevented from more mainstream uptake by reduced yields. Organic agriculture relies on knowledge of intricate biological interactions in place of synthetic inputs used in other forms of agriculture, and in this way reflects an older way of practicing agriculture. Precision agriculture (PA) conversely is a technologically driven method of farming and combines guidance and data collection via remote sensing technologies to bring new efficiencies to farm operations. In this dissertation PA tools were used to explore the potential of improving organic production through site-specific management. By conducting on farm precision experiments (OFPE) with PA farmers can learn quickly about spatial variability across fields enabling well defined management templates. In organic systems this experimentation can be conducted with varied seeding rate inputs of both cover and cash crops. Here, we explored the relevancy of PA in organic settings, first broadly laying the philosophical foundation for the paradigm shift from production-oriented agriculture to precision agroecology. Secondly, a greenhouse experiment was used to develop the first-principle relationship between cover crop and cash crop seeding rates to maximize net return, establishing the basis for field experiments. Field scale experiments on five organic grain farms across the northern great plains deployed OFPE to optimize net returns, or suppress weeds, with varied seeding rates of cover and cash crops. Based on OFPE data, simulations across all sites found net returns could be improved on average by $45.82 ha-1 if economically optimum variable seeding rates were used. While seeding rates were found to have variable effects on weeds across fields, an optimized site-specific seeding strategy to balance net return and weed minimization improved net return and weed suppression compared to farmer-chosen seeding rates in every field tested. Overall, these results reveal the relevancy of precision agriculture to be deployed in organic systems to improve management for increased farmer net returns, and as a weed management method. In this way modern tools can be used to augment farmer knowledge about their local spaces to enable greater understanding and improved management of complex agroecosystems.
The impact of Teosinte branched1 and reduced height mutations in durum wheat
(Montana State University - Bozeman, College of Agriculture, 2021) Brown, McKenna Margaret; Chairperson, Graduate Committee: Michael J. Giroux
Increasing the yield of wheat requires identifying new genetic combinations of alleles by crossing or by creating variation in yield limiting genes. Wheat yield is impacted by tiller number and seeds per tiller, both of which are impacted by the Reduced height (Rht) and Teosinte branched1 (TB1) genes. In this study, durum plants varying for Rht and TB1 alleles created by EMS mutagenesis were studied to determine the impact of each allele upon agronomic and seed traits. Both projects aimed to increase durum yield, one through an increase in tiller number; the other through the development of a plant with height between current full-height and semi-dwarf varieties that can allocate more resources to seed production. The impact of TB1 null alleles were studied alone and together in greenhouse and field trials, along with an RNA sequencing study to determine the impact of TB1 mutation upon global gene expression in developing meristems. TB1 single and double null mutants produced more biomass and tillers per plant, and expression of genes in meristems varied. A screen of wheat varieties grown in Montana identified that several spring and durum wheat varieties contain different TB1 alleles, but none contained TB1 null alleles. Rht experiments included field trials, coleoptile length and gibberellic acid responsiveness assays, and an in-vitro test to determine the impact of each Rht mutation upon binding to Gibberellin Interacting Domain 1 (GID1) that directly influences plant height. It was found that the previously described Rht-B1b-E529K allele reduced both plant height and coleoptile length while two newly characterized Rht mutations had lesser impacts with trends towards intermediate-height plants. The results of this research demonstrate that Rht alleles that alter RHT binding to GID1 and TB1 null alleles may prove useful in increasing durum tillering and optimizing plant height for different growing conditions.
Chickpea variety evaluation and intercropping for disease management and yield
(Montana State University - Bozeman, College of Agriculture, 2022) Zhou, Yi; Chairperson, Graduate Committee: Chengci Chen; This is a manuscript style paper that includes co-authored chapters.
Chickpea (Cicer arietinum L.) is an important food grain legume, but production is constrained by the soilborne pathogen complex, Ascochyta rabiei, and the development of fungicide resistance. Cultivar resistance is one of the most efficient strategies in disease management. However, chickpea cultivars with resistance to soilborne pathogens or complete resistance to A. rabiei have not been developed. Intercropping chickpea-flax has the potential for Ascochyta blight management. To minimize the impact of soilborne disease and Ascochyta blight on chickpea production, refining of integrated pest management practices is essential. To evaluate the effect of cultivar selection in combination with seed treatment on soilborne disease control, twenty-five cultivars/lines were planted with or without fluxapyroxad, pyraclostrobin, and metalaxyl under field conditions. The area under disease progress curve (AUDPC), seed yield, and protein content were assessed. Fusarium solani was isolated and identified in the late season, and the disease severity of root rot was evaluated. The results showed that seed treatment effectively suppressed damping-off and improved chickpea yield but only slightly reduced late-season root rot. The AUDPC of NDC160166 and NDC 160236 was not significantly reduced by seed treatment, which could be a future resource of resistance. To assess the effects of configurations and resistant cultivar on yield and Ascochyta blight management in intercropping chickpea-flax, two chickpea cultivars (CDC Leader and Royal) were planted with flax under six configurations (monocrop chickpea, 70% chickpea-30% flax in mixture, 50% chickpea-50% flax in mixture, 50% chickpea-50% flax in alternate rows, 30% chickpea-70 flax in mixture, monocrop flax). Yield and nutrient content of component crops and Ascochyta blight infection were evaluated. Chickpea yield decreased as flax proportion increased in the mixture. Chickpea yielded higher in the alternate row design than in the mixture at the same seeding rate due to less interspecies competition in the alternate rows. Intercrop increased 2%-23% land productivity. Chickpea-flax intercrop effectively reduced Ascochyta blight under higher disease pressure. The configuration of 50% chickpea and 50% flax in the mixture was more effective in suppressing Ascochyta blight than in the alternate row configuration. Integrated resistant cultivar and intercropping configuration was most effective in disease suppression.
Population dynamics of wheat stem sawfly, Cephus cinctus Norton, in barley in Montana
(Montana State University - Bozeman, College of Agriculture, 2020) Achhami, Buddhi Bahadur; Chairperson, Graduate Committee: David K. Weaver; Gadi V. P. Reddy, Jamie D. Sherman, Robert K. D. Peterson and David K. Weaver were co-authors of the article, 'Antixenosis, antibiosis, and potential yield compensatory responses in barley cultivars exposed to wheat stem sawfly under field conditions' which is contained within this dissertation.; Gadi V. P. Reddy, Jamie D. Sherman, Robert K. D. Peterson and David K. Weaver were co-authors of the article, 'Effect of precipitation and temperature on larval survival of Cephus cinctus (Hymenoptera: Cephidae) in barley cultivars' which is contained within this dissertation.; Robert K. D. Peterson, Jamie D. Sherman, Gadi V. P. Reddy and David K. Weaver were co-authors of the article, 'Multiple decrement life tables of Cephus cinctus Norton (Hymenoptera: Cephidae) across a set of barley cultivars: the importance of plant defense versus cannibalism' which is contained within this dissertation.; Gadi V. P. Reddy, Megan L. Hofland, Robert K. D. Peterson, Jamie D. Sherman and David K. Weaver were co-authors of the article, 'Host selection and oviposition behaviors of Cephus cinctus (Hymenoptera: Cephidae) in barley' which is contained within this dissertation.
Wheat stem sawfly (WSS) is an economically devastating pest of cereals grown in North America. The larva is the only feeding stage and remains confined within a host stem until it emerges as an adult the following year. This limited mobility increases larval vulnerability to mortality factors when host plant traits are hostile to survival. For instance, larval mortality is greater in barley than in solid stemmed wheat cultivars known to be resistant. Both solid stemmed wheat and barley kill neonates via host plant resistance traits. Traditionally, barley was recommended as an alternative rotational crop to prevent WSS outbreaks in wheat crops. There is limited data available regarding barley host plant resistance and questions persist. Has barley resistance changed over time? What is the impact of larval feeding injury on grain yield of barley? Do females display similar oviposition behaviors across barley cultivars that vary in susceptibility? To answer these questions. I conducted field experiments to assess resistance and possible tolerance to WSS in eight barley cultivars. Based on the number of eggs, 'Hockett' was the most attractive cultivar to WSS female (less antixenosis), while 'Craft' and 'Celebration' killed the greatest number of neonates due to antibiosis. Multiple decrement life table studies revealed that plant defense and cannibalism were two major causes of larval mortality. We measured greater yield in infested stems with dead larvae (potential tolerance) than for cut stems and both were greater than uninfested stems in all cultivars except 'Celebration'. A greenhouse study revealed that females preferred 'Hockett' over 'Craft' in frequencies of oviposition behaviors and numbers of eggs deposited. Additionally, a greater amount of the WSS attractant (Z)-3-hexenyl acetate was found in aerations from 'Hockett' plants than from 'Craft.' The amount of defensive compound linalool was greater in aerations from 'Craft' than from 'Hockett.' These results suggest that barley cultivars are equipped with varying levels of antibiosis, antixenosis, and tolerance traits against WSS. Thus, we can exploit these traits in the development of cultivars which can reduce WSS populations and decrease economic loss caused by this species.
Integrating cover crop mixtures in the northern Great Plains: an ecological assessment on crop productivity, biodiversity, and temperature and moisture conditions
(Montana State University - Bozeman, College of Agriculture, 2020) DuPre, Mary Ellyn; Chairperson, Graduate Committee: Fabian D. Menalled and Tim F. Seipel
Cropping systems can impact crop productivity and functioning of biodiversity in the Northern Great Plains, a region heavily reliant on low diversity crop rotations and off-farm inputs, and a region predicted to experience warmer and drier climate scenarios by mid-century. In three complementary studies, I compared the impacts of cover crop mixtures and termination methods on crop productivity and three forms of the associated biodiversity (weeds, soil fungi, and ground beetles), under varying temperature and soil moisture conditions. First, I assessed the impacts of the presence (cover crops and fallow) and composition (cover crop mixtures) of cover crops, termination methods (herbicide, cattle-grazing, and haying), as a function of temperature and soil moisture conditions on crop yields, and weed communities. A 5-species, early-spring mixture generated cooler temperatures, produced more biomass, and suppressed weed biomass under warmer and drier conditions, compared to summer fallow and the 7-species, mid-spring mixture. However, lower soil moisture and subsequent reduced grain yields following the mixtures, especially under warmer and drier conditions, suggests that continuously rotating wheat with mixtures may not be the optimal method to diversify small-grain cropping systems. Second, I assessed the impacts of the presence and composition of cover crops, termination methods and temperature and soil moisture conditions on fungal communities. The early-season cover crop mixture reduced plant pathogen abundance and enhanced AM fungal richness in both the soil and subsequent wheat root crop. The enhancement of beneficial fungi and fewer plant pathogens may be a proxy to better support ecosystem services through the use of cover crop mixtures. Third, I compared ground beetle communities among cover crops treatments and termination methods. Ground beetle activity density was not impacted by termination methods and was greatest in the early-season mixture at the beginning of the growing season and in summer fallow at the end of the growing season, while the mid-season mixture peaked in the middle. Ground beetle diversity peaked in the middle and differed in community composition earlier in the growing season. These results indicate that cover crop mixtures can act as an ecological filter to ground beetle communities to better support pest regulation. Overall, these studies indicate that cover crop mixtures can support crop productivity and the associated biodiversity with changes to temperature and soil moisture, although, with agronomic and ecological trade-offs.
Response of soil bacterial communities to cropping systems, temporal changes, and environmental conditions in the northern Great Plains
(Montana State University - Bozeman, College of Agriculture, 2021) Ouverson, Laura Tindall; Chairperson, Graduate Committee: Fabian D. Menalled
Soil bacterial communities are essential components of the soil ecosystem that support crop production. However, agriculture in semiarid drylands and their associated soil bacterial communities face increasingly warmer and drier conditions due to climate change. Two complementary studies were conducted to assess the response of soil bacterial communities to cropping systems, temporal changes, and soil temperature and moisture conditions in semiarid, dryland agricultural systems of the Northern Great Plains. The first study focused on soil bacterial community response to crop phase in contrasting cropping systems (chemical inputs and no-till, USDA-certified organic tilled, and USDA-certified organic sheep grazed) over a growing season. Organic grazed management supported more diverse bacterial communities than chemical no-till, though diversity in all systems decreased over the growing season. Organic grazed bacterial communities were distinct from those in the organic tilled and chemical no-till systems. An interaction between cropping system and crop phase affected community dissimilarity, indicating that overarching management systems and environmental conditions are influential on soil bacterial communities. The second study evaluated soil bacterial communities in a winter wheat - cover crop or fallow rotation. Observations were conducted in the summer fallow and two cover crop mixtures differing by species composition and phenologies, terminated by three different methods (chemical, grazing, or haying), and subjected to either induced warmer/drier or ambient soil conditions. Only the presence and composition of cover crops affected bacterial community dissimilarity, where mid-season soil bacterial communities were distinct from early season and fallow communities. Bacterial communities responded to an interaction between the presence and composition of cover crops and environmental conditions, but not termination. No treatment effects were observed in bacterial communities in 2019, which could be attributed to above average rainfall. The results of these studies suggest cover crop mixtures including species tolerant to warmer and drier conditions can foster diverse soil bacterial communities compared to fallow soils. Overall, these studies contribute to a better understanding of how soil bacterial communities respond to soil health building practices in the Northern Great Plains. Cropping systems can foster unique soil bacterial communities, but these effects may be moderated by environmental and temporal conditions.
Alternative fruit crops for the northern Rocky Mountain climate: production and quality factors of cultivars
(Montana State University - Bozeman, College of Agriculture, 2020) Setzer, Durc Parker; Chairperson, Graduate Committee: Mac Burgess
The demand for healthy foods is large and increasing. There are many high-antioxidant berry and fruit crops that fit this market but not all are suitable for cold climates. This study evaluates six novel fruit crops for Montana: Aronia, Black and Red Currant, Dwarf Sour Cherry, Haskap and Saskatoon. Trials were planted in 2015 in a randomized complete block design with three blocks per site, at three different sites in Montana. Qualities investigated include yield, fruit mass, soluble solids (SS), and total phenolic content (TPC). The trialed species were generally well suited to Montana. Yields varied among cultivars and yields in Bozeman were smaller than other sites. The following results incorporate data across sites from 2016 to 2018. Yield results are the most mature year. TPC is reported as milligrams of gallic acid equivalent per 100 grams of fresh fruit. Aronia yields averaged 4061 grams, mean fruit mass was 0.89 grams. SS averaged 22° brix. TPC averaged 2800 mg. The cultivar McKenzie produced higher TPC than Viking. Black Currant yields averaged 3784 grams; fruit mass averaged 1.15 grams. Mean SS were 17.5° brix. The cultivar Stikine produced the largest yield, Blackcomb the heaviest fruit, Titania the highest SS. Red Currant yield in Corvallis averaged 5059 grams and mean fruit mass was 0.79 grams. The cultivar Jonkeer van Tets provided the largest yield and fruit mass. Dwarf Sour Cherry yield averaged 6435 grams. Mean fruit mass and SS were 4.1 grams and 16.2° brix, respectively. The cultivar Carmine Jewel produced the largest yield, Lutowka Rose the largest fruit, and Romeo the highest SS. Crimson Passion did not flower at any site. Haskap yield averaged 1364 grams, mean fruit mass was 1.2 grams and mean SS were 15.3° brix. Phenolic content averaged 919 milligrams. The cultivar 85-19 produced the largest yield, Aurora the largest fruit, Indigo Gem the highest SS, and Auroroa and Borealis the highest phenolic contents. Saskatoon mean yield was 1567 grams. Mean fruit mass and SS were 1.02 grams and 20.1° brix, respectively. Northline produced the largest Saskatoon yield, Martin the heaviest fruit and Smoky the highest SS.
Effect of sainfoin (Onobrychis viciifolia Scop.) variety and harvest maturity on quality, yield, and condensed tannin content
(Montana State University - Bozeman, College of Agriculture, 2020) Gardhouse, Kylie Ann; Chairperson, Graduate Committee: Megan Van Emon
Sainfoin (Onobrychis viciifolia Scop.) is a forage legume that was introduced to North America from Europe and Asia. Unlike alfalfa, sainfoin is non-bloating, lacks autotoxicity properties, and may work as an anthelmintic when consumed by livestock. With limited information available on sainfoin varieties and management, new information is necessary to provide to producers for optimal production. The objective of this study was to determine the impact of variety and maturity at harvest on forage yield, quality, and condensed tannin content. Four varieties of sainfoin ('AAC Mountainview', 'Eski', 'Shoshone', and 'Delaney') and one alfalfa variety ('Shaw') were planted at two locations in Montana and the same sainfoin varieties and one alfalfa variety ('Spredor 4') were planted in one location in Utah. Samples were taken at 10, 50 and 100% bloom and evaluated for dry matter production and nutritive quality. Variety (P < or = 0.005) and maturity (P < or = 0.001) both were found to impact production, with Shaw, AAC Mountainview and Eski varieties having higher production, as well as tonnage increasing with advancing maturity than Delaney and Shoshone. Sainfoin had greater levels of condensed tannins than alfalfa (P < or = 0.001), and within sainfoin, tannin content decreased with increasing maturity (P < or = 0.003) at all locations. Crude protein levels were significantly different for maturity (P < 0.001) and variety (P < or = 0.003), and fiber values were only affected by maturity (P < or = 0.001). These results demonstrate that sainfoin is a beneficial legume to feed to livestock particularly in grazing situations, with similar quality and yield compared to alfalfa, as well as a higher condensed tannin content.
Genetic dissection of grain yield and yield component traits in hexaploid spring wheat
(Montana State University - Bozeman, College of Agriculture, 2020) Jones, Brittney Hannah; Chairperson, Graduate Committee: Michael J. Giroux; Nancy K. Blake, Hwa-Young Heo, Jay R. Kalous, John M. Martin, Jessica A. Torrion and Luther E. Talbert were co-authors of the article, 'Improving hexaploid spring wheat by introgression of alleles for yield component traits from durum wheat' in the journal 'Crop science' which is contained within this dissertation.; Nancy K. Blake, Hwa-Young Heo, Jay R. Kalous, John M. Martin, Deanna L. Nash, Jessica A. Torrion and Luther E. Talbert were co-authors of the article, 'Impact of yield component alleles from durum wheat on end-use quality of spring wheat' in the journal 'Cereal chemistry ' which is contained within this dissertation.; Nancy K. Blake, Hwa-Young Heo, John M. Martin, Jessica A. Torrion and Luther E. Talbert were co-authors of the article, 'Allelic response of yield component traits to resource availability in spring wheat' in the journal 'Theoretical and applied genetics' which is contained within this dissertation.
Hexaploid wheat accounts for 30% of global grain production, ranking in the top three major food crop species along with maize and rice. Grain yield from hexaploid wheat is an important agronomic consideration for sustainable agriculture. As the human population continues to grow and the amount of farmable land decreases it is imperative that a focus be placed on improving grain yield performance. Grain yield is a quantitative trait and as such improved performance is largely influenced by genetic variation, environment and genotype x environment interactions. Due to the quantitative nature of grain yield the mechanisms of genetic control are largely unknown. The purpose of the presented research was to genetically dissect grain yield and yield component traits in hexaploid spring wheat grown in Montana in order to leverage new understanding to improve Montana germplasm and future breeding programs. This investigation included three research aims: (i) to determine the genetic impact of introgressed durum yield component alleles on hexaploid spring wheat agronomic and end-use quality performance (Chapters 2 and 3); (ii) investigate how resource availability as simulated by plant competition and seed density impacted yield component allele response at four yield component quantitative trait loci (Chapter 4); and (iii) to better understand the mechanism of genetic control of QTn.mst-6B a quantitative trait locus associated with tiller number through high-resolution mapping (Chapter 5). This research highlights the complexity of pleotropic interaction among yield component traits and variability associated with grain yield as impacted by environment and resources availability. Results from the three aims provide a detailed investigation of single quantitative trait loci for use as novel sources of cultivar improvement and increased genetic gain as well as, a better understanding of grain yield and yield component traits.

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