A. M. Missaoui

• PhD
• Professor (Full) at University of Georgia

Switchgrass (Panicum virgatum L.) is a North American grass species with biofuel potential. Claviceps spp. is known to infect the florets of various grass species, initially characterized by a sticky honeydew exudate and later as sclerotium replacing the seed in the infected ovary (Tanaka et al 2023). Since 2019, from July to October, switchgrass p...

Leveraging the use of multiplex multi-omic networks, key insights into genetic and epigenetic mechanisms supporting biofuel production have been uncovered. Here, we introduce RWRtoolkit, a multiplex generation, exploration, and statistical package built for R and command line users. RWRtoolkit enables the efficient exploration of large and highly c...

Economically viable production of biobased products and fuels requires high-yielding, high-quality, sustainable process-advantaged crops, developed using bioengineering or advanced breeding approaches. Understanding which crop phenotypic traits have the largest impact on biofuel economics and sustainability outcomes is important for the targeted fe...

Tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) is a cool-season perennial grass widely grown for forage and turf. Tall fescue lives in association with a fungal endophyte that helps the grass overcome abiotic and biotic stressors. The endophyte is asexual and transmits vertically from the tall fescue plant to the next generation through the s...

Background Tall fescue (Festuca arundinacea [Schreb.], Lolium arundinaceum [Schreb.] Darbysh) and perennial ryegrass (Lolium perenne) are important cool‐season forage and amenity grasses that have a mutualistic association with an endophytic fungus. Endophytes confer insect and drought resistance to plants but can produce mammalian toxins. Novel en...

Background Tall fescue and perennial ryegrass are important cool-season forage and amenity grasses. Both types of grass have a mutualistic association with an endophytic fungus. Novel endophytes, non-toxic to livestock, have been bred in association with elite cultivars of the two species. It is critically important for producers to ensure that the...

Alfalfa is critical to global food security, and its data is abundant in the U.S. nationally, but often scarce locally, limiting the potential performance of machine learning (ML) models in predicting alfalfa biomass yields. Training ML models on local-only data results in very low estimation accuracy when the datasets are very small. Therefore, we...

The alfalfa crop is globally important as livestock feed, so highly efficient planting and harvesting could benefit many industries, especially as the global climate changes and traditional methods become less accurate. Recent work using machine learning (ML) to predict yields for alfalfa and other crops has shown promise. Previous efforts used rem...

The alfalfa crop is globally important as livestock feed, so highly efficient planting and harvesting could benefit many industries, especially as the global climate changes and traditional methods become less accurate. Recent work using machine learning (ML) to predict yields for alfalfa and other crops has shown promise. Previous efforts used rem...

The prevalence of genetic diversity in switchgrass germplasm can be exploited to capture favorable alleles that increase its range of adaptation and biomass yield. The objectives of the study were to analyze the extent of polymorphism and patterns of segregation distortion in two F1 populations and use the linkage maps to locate QTL for biomass yie...

Cold stress (CS) affects the survivability, geographical distribution, and yield stability of crops. Suitable management and agronomic practices can minimize the crop losses associated with cooler environments. However, agronomic practices alone can't support plants adequately to withstand the harsh cold. Therefore, exploring plants cold stress-res...

Bioenergy production often focuses on the aboveground feedstock production for conversion to fuel and other materials. However, the belowground component is crucial for soil carbon sequestration, greenhouse gas fluxes, and ecosystem function. Roots maximize feedstock production on marginal lands by acquiring soil resources and mediating soil ecosys...

Cool-season grasses are the most common forage types in livestock operations and amenities. Several of the cool-season grasses establish mutualistic associations with an endophytic fungus of the Epichloë genus. The grasses and endophytic fungi have evolved over a long period of time to form host-fungus specific relationships that confer protection...

Cool-season grasses are the most common forage types in livestock operations and amenities. Several of the cool-season grasses establish mutualistic associations with an endophytic fungus of the Epichloe genus. The grasses and endophytic fungi have evolved over a long period of time to form host-fungus specific relationships that confer protection...

Abstract Background Winter freezing temperature impacts alfalfa (Medicago sativa L.) persistence and seasonal yield and can lead to the death of the plant. Understanding the genetic mechanisms of alfalfa freezing tolerance (FT) using high-throughput phenotyping and genotyping is crucial to select suitable germplasm and develop winter-hardy cultivar...

Tall fescue (Lolium arundinaceum (Schreb.) S.J. Darbyshire) often forms a symbiotic relationship with fungal endophytes (Epichloë coenophiala), which provides increased plant performance and greater tolerance to environmental stress compared to endophyte-free tall fescue. Whether this enhanced performance of tall fescue exclusively results from the...

Alfalfa plants are susceptible to numerous diseases caused by fungi, oomycetes, bacteria, and nematode pests that significantly reduce forage yield, quality, and productive stand life. Disease resistance is the most common and effective means of reducing damage from pathogens. Using phenotypic recurrent selection, plant breeders have successfully d...

Understanding the genetics of drought tolerance in hard red spring wheat (HRSW) in northern USA is a prerequisite for developing drought-tolerant cultivars for this region. An association mapping (AM) study for drought tolerance in spring wheat in northern USA was undertaken using 361 wheat genotypes and Infinium 90K single-nucleotide polymorphism...

Understanding the genetics of drought tolerance can expedite the development of drought-tolerant cultivars in wheat. In this study, we dissected the genetics of drought tolerance in spring wheat using a recombinant inbred line (RIL) population derived from a cross between a drought-tolerant cultivar, ‘Reeder’ (PI613586), and a high-yielding but dro...

Background Tall fescue (Lolium arundinaceum (Schreb.) S.J. Darbyshire) is a popular perennial grass species for livestock production and amenities in the United States. Tall fescue often forms a symbiotic relationship with fungal endophytes (Epichloë coenophiala) which provides increased plant tolerance to environmental stress compared to endophyte...

The major forces driving farm-level production for the ever-growing global population have relied upon mechanized farming techniques, synthetic inputs, and developing high-yielding crop varieties. Recently, however, there has been a gradual shift toward developing sustainable approaches addressing the potential use of beneficial traits of the soil-...

Key message Mapping combined with expression and variant analyses in switchgrass, a crop with complex genetics, identified a cluster of candidate genes for leaf wax in a fast-evolving region of chromosome 7K. Abstract Switchgrass ( Panicum virgatum L.) is a promising warm-season candidate energy crop. It occurs in two ecotypes, upland and lowland,...

Energycane (Saccharum hybrid) could be a viable bioenergy crop for the Southeast United States. Five energycane cultivars were planted in 2008 at a northern (Watkinsville, GA) and a southern (Tifton, GA) site, and were grown for 7 yr to compare biomass yields. Plots were arranged in a four replicate randomized complete block design at each site. En...

Switchgrass (Panicum virgatum L.) is a perennial warm-season grass that can serve dual purposes, forage and biofuel feedstock. Because the cell wall accounts for more than half the dry matter weight, breeding for both objectives will largely depend on cell wall components which include cellulose, hemicellulose, and lignin. We used NIRS to measure c...

Nitrogen (N) in the agricultural production system influences many aspects of agroecosystems and several critical ecosystem services widely depend on the N availability in the soil. Cumulative changes in regional ecosystem services may lead to global environmental changes. Thus, the soil N status in agriculture is of critical importance to strategi...

Predicting alfalfa biomass and crop yield for livestock feed is important to the daily lives of virtually everyone, and many features of data from this domain combined with corresponding weather data can be used to train machine learning models for yield prediction. In this work, we used yield data of different alfalfa varieties from multiple years...

Background Switchgrass (Panicum virgatum) undergoes winter dormancy by sensing photoperiod and temperature changes. It transitions to winter dormancy in early fall following at the end of reproduction and exits dormancy in the spring. The duration of the growing season affects the accumulation of biomass and yield. In this study, we conducted QTL m...

Background Switchgrass (Panicum virgatum) undergoes seasonal growth changes based on the perception of photoperiod and temperature. It transitions to winter dormancy in early fall, breaks dormancy in the spring, and resume the cycle starting from flowering which is the cue for senescence. The length of growing season can impact the biomass accumula...

Background Switchgrass (Panicum virgatum) undergoes seasonal growth changes based on the perception of photoperiod and temperature. It transitions to winter dormancy in early fall, breaks dormancy in the spring, and resumes the cycle starting from flowering which is the cue for senescence. The length of the growing season can impact biomass accumul...

Background Switchgrass (Panicum virgatum) undergoes winter dormancy by sensing photoperiod and temperature changes. It transitions to winter dormancy in early fall following at the end of reproduction and exits dormancy in the spring. The duration of the growing season affects the accumulation of biomass and yield. In this study, we conducted QTL m...

Background Switchgrass (Panicum virgatum) undergoes winter dormancy by sensing photoperiod and temperature changes. It transitions to winter dormancy in early fall following at the end of reproduction and exits dormancy in the spring. The duration of the growing season affects the accumulation of biomass and yield. In this study, we conducted QTL m...

Switchgrass (Panicum virgatum), a C4 perennial grass native to North America and developed as a sustainable biofuel feedstock, occurs in two ecotypes, lowland and upland, which vary in their architecture as well as their range of adaptation. In this study, we assessed single nucleotide polymorphism (SNP) variation in 372 switchgrass genotypes for n...

In agroecosystems, nitrogen is one of the major nutrients limiting plant growth. To meet the increased nitrogen demand in agriculture, synthetic fertilizers have been used extensively in the latter part of the twentieth century, which have led to environmental challenges such as nitrate pollution. Biological nitrogen fixation (BNF) in plants is an...

In the article [1], in ‘Methods’ section and ‘G x E and heritability’ subsection, there is an error in the formula of heritability (H2).

Background: Switchgrass is an emerging bioenergy crop due to its perennial nature, high biomass yield, and ability to grow in marginal land. The high genetic diversity in switchgrass germplasm can be exploited to capture favorable traits that increase the range of adaptation and biomass yield. Genetic diversity can be explored using single nucleoti...

Background: The genetic and genomic basis of flowering time and biomass yield in alfalfa (Medicago sativa L.) remains poorly understood mainly due to the autopolyploid nature of the species and the lack of adequate genomic resources. We constructed linkage maps using genotyping-by-sequencing (GBS) based single dose allele (SDA) SNP and mapped alfa...

Camelina [Camelina sativa (L.) Crtz.] of the Brassicaceae family is an annual oilseed crop that has received increasing attention as a biofuel feedstock because of its excellent adaptability to low fertility drylands. Even though moisture is one of the critical factors affecting plant growth and seed yield, genetic studies on response to water defi...

Alfalfa leaf rust caused by the fungal pathogen Uromyces striatus compromises forage yield and quality. We investigated the genetic basis of leaf rust resistance in alfalfa using a F1 mapping population segregating for resistance to the disease in addition to segregation for fall dormancy (FD) and winter hardiness (WH). The objective of this work w...

Direct seeding techniques often result in unsatisfactory outcomes in rangeland rehabilitation, primarily because of low seedling emergence and poor establishment. Seed processing techniques aimed at improving seedling emergence have gained interest by pasture managers. The purpose of this study was to investigate the combined effects of bracteole r...

Understanding key adaptation traits is crucial to developing new cultivars with broad adaptations. The main objective of this research is to understand the genetic basis of winter hardiness (WH) and fall dormancy (FD) in alfalfa and the association between the two traits. QTL analysis was conducted in a pseudo-testcross F1 population developed from...

Current knowledge of yield potential and best agronomic management practices for perennial bioenergy grasses is primarily derived from small-scale and short-term studies, yet these studies inform policy at the national scale. In an effort to learn more about how bioenergy grasses perform across multiple locations and years, the U.S. Department of E...

Cereal rye (Secale cereale L.) is widely used as cover crop because of its allelopathic effects and effectiveness in weed suppression. In the Southeastern US, rye is traditionally grown for winter grazing in dormant bermudagrass pastures, where alfalfa (Medicago sativa L.) is increasingly planted as a companion crop. The effect of cereal rye on alf...

Summer dormancy is an evolutionary response that some perennial cool-season grasses adopted as an avoidance strategy to escape summer drought and heat. It is correlated with superior survival after severe summer droughts in many perennial grass species originating from Mediterranean environments. Understanding the genetic mechanism and environmenta...

‘Renovation’ (Reg. No. CV-9, PI 680615), is a large-leaved, synthetic intermediate type white clover (Trifolium repens f. hollandicum Erith ex Jav. & Soo) cultivar derived after hybridizing (i.e., population crosses) random, individual plants from a naturalized ecotype population from Oklahoma with those from the ‘Regal’, ‘Patriot’, ‘Tillman’, and...

Molybdenum (Mo) is a critical micronutrient for nitrogen fixation in legumes. Low pH limits the availability of Mo therefore reducing nodulation and nitrogen fixation. This study investigates the effect of Mo supplementation on alfalfa nodulation and its correlation with root and shoot biomass in low pH soil. Three experiments were conducted in the...

Salt impedes plant growth and yield. This study was conducted to explore the effect of plant growth stimulants (seaweed extract, humic acid) and potassium sulfate in alleviating salt stress in barley (Hordeum vulgare L.). Initially, 10 barley genotypes were germinated in a growth chamber at five salt levels (0, 0.5, 1.0, 1.5, and 2.0%). Increasing...

Two main types of summer dormancy in tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] are recognized, eco-dormancy and endo-dormancy. Endo-dormancy is a physiological response to environmental signals leading to slowing of metabolic activity in meristematic tissues and most likely controlled by circadian clock genes. Therefore, it is genetic...

Salinity is a major impediment to crop production. This study was undertaken to compare the effect of seaweed extract, humic acid, and potassium sulfate nanoparticles in alleviating salt stress in Alfalfa (Medicago sativa L.). Seeds of ten alfalfa genotypes were germinated in a growth chamber at five salt concentrations (0%, 0.5%, 1.0%, 1.5%, and 2...

A greenhouse study was conductedto explore the effect of various rates of potassium sulfate (K2SO4) nanoparticles on alfalfa (Medicago sativaL.) growth and physiological response under salt stress. One salt-tolerant genotype (Me-sa -Sirsa) and one salt-sensitive genotype (Bulldog 505) were selected based on germination under salt and were planted i...

Abstract Seasonal dormancy is an adaptive mechanism where plants suspend growth and become physiologically inactive to avoid extreme environmental conditions. Environmental factors like temperature, photoperiod, nutrients, and soil moisture control plant growth and development through various complex molecular mechanisms. Crown and seed dormancy of...

Salinity is a major impediment to crop production. This study was undertaken to compare the effect of seaweed extract, humic acid, and potassium sulfate nanoparticles in alleviating salt stress in Alfalfa (Medicago sativa L.). Seeds of ten alfalfa genotypes were germinated in a growth chamber at five salt concentrations (0%, 0.5%, 1.0%, 1.5%, and 2...

Salinity is a major impediment to crop production. This study was undertaken to compare the effect of seaweed extract, humic acid, and potassium sulfate nanoparticles in alleviating salt stress in Alfalfa (Medicago sativa L.). Seeds of ten alfalfa genotypes were germinated in a growth chamber at five salt concentrations (0%, 0.5%, 1.0%, 1.5%, and 2...

Tall fescue [Lolium arundinaceum (Schreb.) Darbysh] is a cool-season perennial grass with two major types of germplasm, Continental and Mediterranean. Most Mediterranean germplasm exhibit summer dormancy even when conditions are favorable for growth. Phenotyping summer dormancy in the field is difficult and costly. The objectives of this study are...

Annual ryegrass (Lolium multiflorum Lam.) is a highly nutritive, fast-growing, C3 cool-season annual forage. Blast or gray leaf spot is a fungal disease of ryegrass caused by Magnaporthe orygae (anamporph Pyricularia oryzae). The disease kills seedlings as well as adult plants. Blast-resistant annual ryegrass cultivars are not available at present....

Alfalfa (Medicago Sativa L.) is increasingly adopted in the southeastern USA as a companion crop in bermudagrass (Cynodon dactylon L.) pastures, where poultry litter is excessively used as source of N fertilizer. This research explores the extent of genetic variation in phosphorus (P) accumulation and uptake in alfalfa germplasm grown in a soil hea...

Switchgrass (Panicum virgatum L), a native perennial of the North American prairie, possesses high biomass yield potential in marginal environments with limited input. It is an outcrossing tetraploid (2n = 4x = 36) with disomic inheritance. Previous research on cultivar improvement was focused primarily on herbage yield and forage digestibility. Th...

The soybean [Glycine max (L.) Merr.] germplasm line G01‐PR16 (Reg No. GP‐371, PI 659503) was developed and released by the Georgia agricultural experiment stations in October 2007. It was released for its combination of resistance to Asian soybean rust (ASR; caused by Phakopsora pachyrhizi Syd.), bacterial pustule [caused by Xanthomonas campestris...

Frogeye leaf spot (FLS), caused by Cercospora sojina K. Hara, is a common disease of soybean [Glycine max (L.) Merr.] in most soybean-growing countries of the world. Significant yield losses of soybean (10-60%) have been attributed to FLS under hot and humid growing conditions. The FLS in the southern United States has been kept under control by pl...

Frogeye leaf spot (FLS), caused by Cercospora sojina Hara, has become a more frequent disease in soybean, Glycine max (L.) Merr., across the USA. The Rcs3 gene provides resistance to all known races of C. sojina. To provide resources for efficient marker-assisted selection (MAS) of Rcs3, we developed and evaluated several single nucleotide polymorp...

Frogeye leaf spot (FLS), caused by Cercospora sojina Hara, is a serious disease of soybean [Glycine max (L.) Merr.]. Complete resistance to all isolates of FLS was reported in the cultivar Davis, and the Rcs3 gene was mapped on Linkage Group J (LGJ), near the simple sequence repeat (SSR) markers Satt244 (64.9 cM) and Satt547 (67.7 cM). The objectiv...

Asian soybean rust (ASR), caused by Phakopsora pachyrhizi Syd., is a widespread disease of soybean [Glycine max (L.) Merr.] with the potential to cause serious economic losses. The objective of this study was to genetically map red‐brown lesion type resistance from the cultivar Hyuuga. A population of 117 recombinant inbred lines (RILs) from the cr...

Information regarding the amount of genetic diversity is necessary to enhance the effectiveness of breeding programs and germplasm conservation efforts. Genetic variation between 21 switchgrass genotypes randomly selected from two lowland (‘Alamo’ and ‘Kanlow’) and one upland (‘Summer’) synthetic cultivars were estimated using restriction fragment...

Developing crop cultivars with high P uptake may prevent the accumulation of phosphorus in the soil and its escape to streams and water reservoirs. The purpose of this investigation was to assess the potential for P uptake in switchgrass (Panicum virgatum L.), an important bioenergy and forage crop, and to determine the nature of genetic variation...

We report an early investigation into genomic organization and chromosomal transmission in switchgrass based on restriction fragment length polymorphism (RFLP) markers. The segregation of 224 single dose restriction fragments (SDRF) in 85 full-sib progeny of a cross between the genotypes Alamo (AP13) and Summer (VS16) was used to determine linkage...

Switchgrass (Panicum virgatum L.) is a model bioenergy species with a high biomass production from which renewable sources of fuel and electricity can be generated. The objective of this study was to perform divergent single-plant selection for biomass yield at low plant density, intermate the selected plants in polycrosses, and evaluate the perfor...

“Matua prairie grass” (Bromus willdenowii Knuth) bromegrass is regarded as high quality forage particularly adapted to hay but may also be used for grazing. Little is known about the growth response to nitrogen (N) fertilization or its potential to accumulate nitrate (NO3 ). Effects of N fertilization were investigated in two greenhouse experiments...

Grasslands “Gala” (Bromus stamineus Desv.) bromegrass is generally regarded as high quality forage particularly adapted to grazing, but little is known about its growth response to N fertilization or potential to accumulate nitrate (NO3 ). Effects of N fertilization were investigated in two greenhouse experiments. Gala was grown in pots in a comple...

Frogeye leaf spot (FLS), caused by Cercospora sojina Hara, is a serious disease of soybean (Glycine max (L.) Merr.). Complete resistance to all isolates of FLS was reported in the cul- tivar Davis, and the Rcs3 gene was mapped on Linkage Group J (LGJ), near the simple sequence repeat (SSR) markers Satt244 (64.9 cM) and Satt547 (67.7 cM). The object...

Research was conducted to explore the genomic organization of switchgrass (Panicum virgatum L.) and its potential for bioenergy and bioremediation to excess P in the soil. The utility of nrDNA ITS1-5.8S-ITS2 region and chloroplast trnL(UAA) intron in determining relatives of switchgrass in the genus Panicum were evaluated using 42 Panicum taxa. The...