Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Thesis (MTech. degree in Agriculture.)--Tshwane University of Technology, 2011. / This study evaluated plant growth and symbiotic performance of four promiscuous-nodulating soybean genotypes and three commercial varieties supplied with a peat-based inoculant of Bradyrhizobium japonicum strain WB74 at three field sites in Mozambique and a pot experiment in South Africa. The sole aim was to assess whether these promiscuous-nodulating soybean genotypes can benefit from inoculation.

Recent preliminary data have suggested that microbe-to-plant signals, and plant internal signals elicited by microbial signals, affect aspects of plant physiology, development and growth. The reported research investigated the responses of plants to signal compounds of microbial and plant origin, such as lipo-chitooligosaccharides (LCOs - signal molecules in rhizobia-legume associations), chitin and chitosan (present in fungal cell walls), and phenolic compounds (salicylic acid, acetylsalicylic acid and gentisic acid - internal signals in plants, often affected by signals from microbes). Phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) are key enzymes of the phenylpropanoid pathway. Oligomers of chitin and chitosan increased the activities of both PAL and TAL in soybean leaves. The degree of increase was dependent on oligomer chain length and time after treatment. LCO [Nod Bj V (C18:1 , MeFuc)] was isolated from Bradyrhizobium japonicum strain 532C. When Arabidopsis thaliana plants were grown for two weeks on agar containing this LCO (10-8M) or chitin pentamer (10-4 M), they had greater root length, root diameter, root surface area and number of root tips than control plants. Chitosan (tetramer and pentamer) did not have this effect. Chitin and chitosan were also tested for effects on corn and soybean photosynthetic rates and growth. High molecular weight chitosan generally reduced photosynthetic rates, but did not reduce the growth of corn or soybean. However, foliar application of 10-6 M LCO to corn leaves increased photosynthetic rates (up to 36%). Foliar application of lumichrome (10-5 and 10-6 M), a breakdown product of riboflavin produced by some rhizosphere bacteria, to corn (C4 plant) and soybean (C3 plant) increased photosynthetic rates (up to 6%). Foliar application of lumichrome (10-5 M) increased soybean leaf area and shoot dry weight. Foliar application of SA, acetyl salicylic acid (ASA) and gentisic acid (GT

North Dakota soybean [Glycine max (L.) Merrill] management varies across the state, resulting in yield differences. Eight soybean seeding rates (starting at 197600 and increasing by 49400 live seed ha-1 increments) and row spacing (30 and 61 cm) were evaluated in 15 North Dakota environments in 2017-2018 to determine plant densities, seed yield, and plant loss, which were compared with soybean producer field data. Planting 30 cm row spacing yielded 183 kg ha-1 greater than 61 cm row spacing. On farm, maximum yields occurred at 414000 live seed ha-1 and final plant densities of 352000 plants ha-1. In research plots, 494000 live seed ha-1 had the highest yield. On farm, 8.9% plant loss occurred after plant establishment while research data observed 6.9% plant loss. North Dakota soybean producers should use narrow row spacing, use final plant density to estimate yields, and 444600 live seed ha-1 provided the highest net revenue. / North Central Soybean Research Program / North Dakota Soybean Council

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Soybean (Glycine max (L.) Merr.) is a subtropical legume that requires root zone temperatures (RZTs) in the 25 to 30$ sp circ$C range for optimal symbiotic activity. The inability of soybean to adapt to cool soil conditions limits its development and yield in short season areas. In particular, nodulation and N$ sb2$ fixation by this subtropical crop species is sensitive to cool (RZT). The objectives of this thesis were to determine whether or not PGPR could be used to help overcome the low RZT inhibition of soybean nodulation, to improve soybean nitrogen fixation and yield under field conditions and to determine the methods by which such increases occurred. The work reported in this thesis has demonstrated that PGPR can increase early season nodulation and total seasonal nitrogen fixation and yield of soybean growing in an area with cool spring soils. The ability of PGPR to stimulate soybean nodulation and growth was shown to be related to their ability to colonize soybean roots, and this was shown to be related to RZT. All steps in early nodulation were stimulated by the presence of PGPR. The beneficial effects of PGPR are exerted through a diffusible molecule excreted into the growth medium. The addition of genistein, a plant-to-bacteria signal molecule already shown to stimulate soybean N$ sb2$ fixation at low RZT, plus PGPR causes increases in soybean nodulation, N$ sb2$ fixation, and growth that were greater than those caused by the addition of PGPR alone, but only at 25 and 17.5$ sp circ$C, and not at 15$ sp circ$C RZT.