Dissertations / Theses on the topic 'Soybean maturity'

The occasional failure of glyphosate to control all weeds throughout the entire growing season has prompted growers to sometimes use herbicides other than glyphosate on glyphosate-tolerant soybean. Field studies were conducted in 1999 and 2000 to investigate potential crop injury from several herbicides on glyphosate-tolerant soybean, and to determine the relationship between soybean maturity, planting date, and herbicide treatment on soybean injury, leaf area index (LAI), and yield. Three glyphosate-tolerant soybean cultivars representing maturity groups III, IV and V were planted at dates representing the full-season and double-crop soybean production systems used in Virginia. Within each cultivar and planting date, 15 herbicide treatments, in addition to a control receiving only metolachlor preemergence, were applied to cause multiple levels of crop injury. Results of this study indicate that glyphosate-tolerant soybean generally recovered from early-season herbicide injury and LAI reductions; however, reduced yield occurred with some treatments. Yield reductions were more common in double-crop soybean than in full-season soybean. In full-season soybean, most yield reductions occurred only in the early maturing RT-386 cultivar. These yield reductions may be attributed to the reduced developmental periods associated with early maturing cultivars and double-crop soybean that often lead to reduced vegetative growth and limited LAI. Additional reductions of LAI by some herbicide treatments on these soybean may have coincided with yield reductions; however, reduced LAI did not occur with all yield reducing treatments. Therefore, soybean LAI response to herbicide treatments does not always accurately indicate the potential detrimental effects of herbicides on soybean yield. Further, yield reductions associated with herbicide applications occurred, although soybean sometimes produced leaf area exceeding the critical LAI level of 3.5 to 4.0 which is the minimum LAI needed for soybean to achieve maximum yield.
Master of Science

Low adoption to cover crops in the northern Plains is due to limited soil water for stand establishment, short growing season, and few adapted winter-hardy species. Studies were conducted to evaluate the impact of interseeded winter camelina [Camelina sativa (L.) Crantz] and winter rye (Secale cereale L.) using different soybean relative maturities, planting date, and row spacing on cover crop biomass, canopy coverage, plant density, soybean yield, and wheat (Triticum aestivum L.) yield the following year. Early-maturing soybean cultivars, produced increased cover crop biomass and canopy coverage, with winter rye outperforming winter camelina. Row spacing showed no effect on cover crop growth, yet narrow rows produced higher soybean yield. Spring wheat is not recommended to plant following winter rye, yet there was no negative effect from winter camelina. Interseeding cover crops into soybean in the northern Plains is possible, but relative low amounts of fall cover crop biomass is produced.

Soybean accounts from more than half of the acres dedicated to row crop production in the mid-south, leading to a wide planting window from late-March through mid-July. Studies were conducted in 2013 and 2014 evaluating seven planting dates of soybean, and their impact on agronomics. As planting was delayed, plant heights significantly increased, increasing the potential for lodging. Canopy closure significantly decreased as planting was delayed, leaving soybean more vulnerable to caterpillar pests. Yield potential also significantly decreased as planting was delayed. Season long surveys of insect pests and their arthropod natural enemies were conducted from 2013 to 2014 in small plot studies, and in large plot studies from 2015 to 2016 across multiple planting dates. The most common insect pests encountered in both studies were bean leaf beetles, the stink bug complex, and soybean looper. The most common natural enemies encountered were lady beetles, spiders, and the assassin bug complex. In general, insect pests densities increased as planting was delayed, whereas natural enemies were higher in earlier plantings or had no change throughout the planting windows. With the increased difficulty of controlling some caterpillar pests such as soybean looper, new control tactics need to be evaluated. A simulated Bt treatment was evaluated against a threshold, bug only, and untreated control across multiple plantings in 2013 and 2014. The simulated Bt treatment yielded significantly higher than the untreated control at plantings from early-June through mid-July. These were the only plantings that reached action threshold for soybean looper. The simulated Bt and threshold treatments were not significantly different from one another. In 2015 and 2016, a simulated Bt treatment plus threshold was evaluated in a late planting situation. The simulated Bt plus threshold treatment yielded significantly higher than the untreated control at the early-June and early-July plantings. Also in 2015 and 2016, the simulated Bt treatment was evaluated against a grower check on producer fields at 23 locations. The simulated Bt treatment resulted in significantly higher soybean yields than the grower check.

Soybean yield differences are a combination of the genotype, environmental conditions, and management practices. Understanding how these factors interact through the analysis of the components involved in yield determination, provides a way to increase potential and actual yields in Kentucky. Two irrigated experiments were conducted to quantify differences in the mechanisms of yield determination across soybean maturity groups (MG) 2 to 5 (Chapter 1), and to quantify management options (seeding rate and choice of MG cultivar) that increase yield potential of double crop soybean systems (Chapter 2). Results showed that cultivars used different physiological strategies to achieve high yields, but these were not always consistent across the environments studied. High yields were often associated to a higher efficiency partitioning biomass to seeds that lead to a higher seed number in some cultivars, as well as associated to low seed growth rates (Chapter 1). The choice of MG cultivar had a greater impact on double-crop soybean yields than increasing seeding rates from 40 to 54 seed m-2. The higher seeding rate increased yields by 5% without an interaction with cultivar. Optimal MG choices for double-crop soybean in KY were dependent on the environment.

Relatively little change in national soybean (Glycine max) yield over the previous years have led many farmers to creating management regimes focused on plant stress. Field experiments consisting of two different relative maturity (2.8RM and 4.5 RM) soybean cultivars were established at three locations across Kentucky in 2013 and 2014. Each maturity group received a single application, sequential applications, or a combination of the following treatments: N’N-diformyl urea, lactofen, lambda-cyhalothrin with thiamethoxam, and azoxystrobin with propiconazole. Relative maturity and yield environment*treatment interactions were observed to be significant (p 0≤.05). 4.5 RM soybean cultivars yielded significantly greater (800 kg ha-1) than 2.8 RM cultivars. Compared to the untreated check, no treatment in the yield environment*treatment interaction significantly increased yield. Significant yield decrease varied across yield environment, but was observed for treatments containing a combination of lactofen and N’N-diformyl urea. Application of stress management practices was not a consistent approach to improving soybean yield.

Soybeans are an economically important plant, with an annual crop value that consistently exceeds 20 billion dollars in the United States alone. A recent increase in demand for soybeans, stemming from its diverse applications in products such as animal feed, oil, and biofuel, has created an emphasis for soybean breeders in value added cultivars. These cultivars, have improved, or altered, agronomic or seed composition traits, allowing them to be efficiently utilized in a specific niche of the processing industry. Facilitating the development of such cultivars requires a thorough understanding of the genetic factors that affect the manifestation of value added traits. Value added traits investigated in this study include seed sucrose, raffinose, stachyose, and phytate content, seed weight, and maturity. The objective of the first part of this project was to characterize the source of low seed stachyose in soybean line PI200508. Two F2 populations, developed from PI200508 and soybean introductions which exhibited higher seed stachyose content were utilized in a QTL analysis approach that incorporated the use of the Williams82 whole genome shotgun (WGS) sequence (http://www.phytozome.org) in a candidate gene mapping approach. A predicted soybean galactosyltransferase gene was established as a candidate gene due to its observed segregation with the single low stachyose QTL observed on molecular linkage group (MLG) C2 in both populations. Sequencing of this putative gene revealed a unique 3 bp deletion in PI200508. A marker developed to exploit this deletion accounted for 88% and 94% of the phenotypic variance for seed stachyose content in the two experimental populations, highlighting its potential for use in marker assisted selection of the PI200508 source of low raffinose and stachyose. The second part of this project involved QTL analysis of seed sucrose, raffinose, stachyose, and phytate content, as well as seed weight in a linkage map for a F8 RIL population developed from the Glycine max line V71-370 and the Glycine soja introduction PI40712. Analysis across all 20 soybean MLG identified 25 QTL for these traits on MLG A1, A2, C2, D1b, D2, F, G, H, I, L, M, O. Nine of these QTL were supported across multiple environments, indicating that they, and their associated markers, could be useful to breeders working with these traits. The third part of this project used the same F8 RIL linkage map to investigate time to maturity (Reproductive stage R8). V71-370 and PI407162 differ in time to maturity when grown in Virginia, and the RILs developed from this cross displayed a wide range in maturity. Two major QTL were identified on MLG H and L. Examination of the Williams82 WGS sequence in these QTL regions revealed two predicted genes with homology to Arabidopsis thaliana light response and photoperiodism genes which were investigated as candidate soybean maturity genes. Markers developed from these predicted genes showed close association with the observed QTL, and could facilitate the further investigation of this complex trait.
Ph. D.

In North Dakota, soybean is typically planted in mid to late May; however, a late spring frost or flooding event may cause a grower to plant late, or replant their crop. The objective of this research was to determine the influence of seeding date, cultivar maturity rating (CMR), and environment on the growth and development of soybean. Six seeding dates were established from 23 May to 9 July using soybean CMR of 00.9, 0.7, and 1.4 at Carrington, Prosper, and Lisbon, ND. The experimental design was a randomized complete block with a 6x3 factorial. The interaction of date by CMR indicated that yield decreased as seeding was delayed further into the growing season with yields becoming less than economical in soybean seeded after 22 June. Soybean with CMR of 00.9 and 0.7 are best suited for delayed seeding in North Dakota, while CMR 1.4 rapidly loses yield with delayed seeding.
North Dakota Soybean Council

Soybeans (Glycine max L.) are an important crop globally for its food, feed, and oilpurposes. It is impacted by many diseases, including Cercospora sojina, the causal agent of Frogeye Leaf Spot (FLS). Chemical and cultural controls to this fungal pathogen are insufficient, so genetic resistance must be acquired for adequate control. To this end, two recombinant inbred populations were screened in a greenhouse setting for their relative resistance to FLS, and their genomes were analyzed for contributing quantitative trait loci (QTL). In the Essex ́ Forrest population, one QTL was discovered on chromosome 13, and in the Forrest ́ Williams 82 population, two QTL were identified on chromosomes 6 and 11, respectively. These populations were then also screened in a field setting for agronomic traits. These traits were analyzed to detect one superior line for both FLS resistance and advanced agronomic traits, F ́W 125. This line should be used in future breeding projects to increase FLS resistance and reduce linkage drag for other desired characteristics.

Winter cover crops grown in rotation with grain crops can be an efficient integrated pest management tool (IPM). However, cover crop biomass production and thus successful provisioning of ecosystem services depend on a timely planting and cover crop establishment after harvest of a cash crop in the fall. One potential management adaptation is the use of short-season soybeans to advance cover crop planting date in the fall. Cover crops planted earlier in the fall may provide a greater percentage of ground cover early in the season because of higher biomass accumulation that may improve weed suppression. However, adapting to short-season soybeans could have a yield penalty compared to full-season soybeans. In addition, it is unclear if further increasing cover crop growing season and biomass production under environmental conditions in Kentucky could limit nitrogen and water availability for the next cash crop. This thesis combines the use of field trials and a crop simulation model to address the research questions posed. In Chapter 1, field trials evaluating yield and harvest date of soybean maturity group (MG) cultivars from 0 to 4 in 13 site-years across KY, NE, and OH, were used to calibrate and evaluate the DSSAT crop modeling software (v 4.7). The subsequent modeling analysis showed that planting shorter soybean maturity groups (MG) would advance date of harvest maturity (R8) by 6.6 to 11 days per unit decrease in MG for May planting or by 1 to 7.3 days for July planting. The earliest MG cultivar that maximized yield ranged from MG 0 to 3 depending on the location, allowing a winter-killed cover crop to accumulate between 257 to 270 growing degree days (GDD) before the first freeze occurrence when soybean was planted in May, and between 280 to 296 GDD when soybean was planted in July. Winter-hardy cover crops could accumulate 701 to 802 GDD following soybean planted in May and 329 to 416 GDD after soybean planted in July. In Chapter 2, a two-year field trial was conducted at Lexington, KY to evaluate the effect of a soybean – cover crop rotation with soybean cultivars MG 1, 2, 3 or 4 on cover crop biomass and canopy cover, and on weed biomass in the fall and the following spring. Results showed that having cover crops was an efficient management strategy to reduce weed biomass in the fall and spring compared to no cover treatment. Planting cover crops earlier in the fall after a short-season soybean increased cover crop biomass production and percentage of ground cover in the fall, but not the following spring. Planting cover crop earlier after a short-season soybean did not improve weed suppression in the fall or spring compared to a fallow control with full-season soybean. Having a fall herbicide application improved weed control when there was a high pressure of winter annual weeds. By the spring, delaying cover crop termination increased cover crop biomass but also did weed biomass. In Chapter 3, a soybean – cover crop – corn rotation was simulated to evaluate the effect of different soybean MG and cover crop termination, as well as year to year variability on water and nitrogen availability for the next corn crop in Lexington, KY. Simulations showed that when cover crops were terminated early, they did not reduced soil available water at corn planting. However, introducing a non-legume cover crop reduced total inorganic nitrogen content in the soil profile by 21 to 34 kg ha-1 implying 15 to 30 kg ha-1 less in corn nitrogen uptake. Cover crop management that was able to maintain similar available water values than fallow treatment while minimizing nitrogen uptake differences was cover crops planted after soybean MG 4 with an early termination. However, the best management strategies that will maximize ecosystem services from cover crops as well as cash crop productivity may need to be tailored to each environment, soil type, irrigation management, and must consider year-to-year variability.

Metribuzin is an alternative herbicide to control glyphosate-resistant common ragweed (Ambrosia artemisiifolia L.) in soybean (Glycine max L. Merr). Metribuzin has potential to injure soybean. A screening technique to grow soybean genotypes in hydroponic solution was developed to determine differences in tolerance and sensitivity. Twenty-two named and experimental genotypes from the North Dakota State University breeding program were screened for visual injury rating, root and shoot weight, and plant height. Metribuzin ? genotype interaction was significant for visual injury rating and shoot weight in both greenhouse experiments. Two tolerant and two sensitive genotypes were screened in the field for tolerance at three rates of metribuzin on soils with pH greater than 7.5. Although some genotypes were more sensitive to metribuzin in the greenhouse, none of the genotypes were sensitive to metribuzin in the field.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2017-04-26T15:01:07Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_daniel_andrei_robe_fonseca.pdf: 1430729 bytes, checksum: 07efb0f1cacfb62b323dc8b13089a7d9 (MD5)
Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-05-02T18:23:35Z (GMT) No. of bitstreams: 2 tese_daniel_andrei_robe_fonseca.pdf: 1430729 bytes, checksum: 07efb0f1cacfb62b323dc8b13089a7d9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-05-02T18:26:07Z (GMT) No. of bitstreams: 2 tese_daniel_andrei_robe_fonseca.pdf: 1430729 bytes, checksum: 07efb0f1cacfb62b323dc8b13089a7d9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Made available in DSpace on 2017-05-02T18:26:23Z (GMT). No. of bitstreams: 2 tese_daniel_andrei_robe_fonseca.pdf: 1430729 bytes, checksum: 07efb0f1cacfb62b323dc8b13089a7d9 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-05-06
Sem bolsa
O objetivo do trabalho foi avaliar a distribuição de umidade durante a fase de maturação fisiológica das sementes de soja nas condições de solo do extremo sul do Brasil. O experimento foi realizado na Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), na unidade Clima Temperada – Estação Experimental Terras Baixas, localizado no município de Capão do Leão – RS. Foram utilizadas as cultivares BMX Turbo RR de hábito de crescimento indeterminado, grupo de maturação 5.8, ciclo super-precoce e BMX Ativa RR de hábito de crescimento determinado, grupo de maturação 5.6, ciclo super-precoce. Para avaliação da dispersão umidade das sementes dentro da mesma planta, foram marcadas cem plantas pelo mesmo estágio de maturação. A colheita começou no amarelecimento das primeiras vagens na planta, e depois disso, a cada dois ou três dias, duas plantas foram colhidas de cada cultivar. Para a safra 2012/2013 foram realizadas treze colheitas durante vinte oito dias. Já na safra 2013/2014 foram realizadas sete colheitas durante quatorze dias, sendo as vagens destacadas uma a uma de cada planta e debulhadas manualmente para a determinação de umidade de cada legume. O hábito de crescimento das cultivares de soja, para grupos de maturação similares, não influencia nas médias de umidade durante o processo de secagem a campo de sementes de soja, compreendido entre o ponto de maturidade fisiológica e o ponto de colheita. No ponto de colheita, a variação de umidade de sementes em uma planta de hábito de crescimento determinado é menor do que a encontrada em sementes de uma planta de hábito indeterminado. O período em que as primeiras sementes entram no estádio de maturação fisiológica pode variar de 15 a 25 dias até o ponto possível da realização da colheita.
The objective was to evaluate the moisture distribution during physiological maturity of soybean seeds in irrigated soil conditions. The experiment was conducted in the Brazilian Agricultural Research Corporation (EMBRAPA), the Temperate Climate unit - Experimental Lowlands Station, located in the municipal district Lion - RS. We used the BMX Turbo RR cultivars indeterminate growth habit, maturity group 5.8, certain super-early maturity and BMX Active RR growth habit, maturity group 5.6, superearly maturity. To evaluate the dispersion seed moisture within the same plant were marked hundred plants at the same stage of maturity. Harvesting began yellowing of the first pod in the plant, and after that, every two or three days, two plants of each genotype were taken. For the 2012/2013 harvest were made thirteen crops for twenty eight days. In the season 2013/2014 seven samples were collected for fourteen days, the highlighted pods one by one from each plant and manually threshed for the determination of moisture each vegetable. The growth habit of soybean cultivars, similar to maturity groups does not influence the moisture medium during the process of drying the soybean field between the physiological maturation and harvesting stage. At the point of harvest, seed moisture variation in a given plant growth habit is lower than that found in seeds of a plant undefined habit. The period in which the first seeds enter the physiological maturity can vary from 15 to 25 days to the possible point of actual harvest.

Greenhouse and microplot studies were conducted for understanding the effects of cover crop species/cultivars for hosts and population reduction of soybean cyst nematode (SCN; Heterodera glycines) from the fields of North Dakota. Moreover, early-maturing soybean [Glycine max (L.)] accessions from different countries of origin were screened for resistance against two common SCN populations for finding new sources of resistance. Thirty-eight cover crop species/cultivars were evaluated for their hosting ability of two SCN populations (SCN103 and SCN2W) from two fields of North Dakota in greenhouse experiments. The majority of the tested crops were non-hosts for both SCN populations. However, a few of them, such as Austrian winter pea (Pisum sativum L.), crimson clover (Trifolium incarnatum L. cv. Dixie), crambe (Crambe abyssinica, cv. BelAnn), field pea, cvs. Aragorn and Cooper, hairy vetch (Vicia villosa Roth), turnip (Brassica rapa L. cv. Purple top), and white lupine (Lupinus albus L.) were poor-hosts/hosts of both SCN populations. Furthermore, thirteen of them were tested for the SCN population reduction either or both in the greenhouse and microplot experiments. Out of 13, at least four crops, such as annual ryegrass (Lolium multiflorum L.), brown mustard (Brassica juncea L. cv. Kodiak), daikon radish (Raphanus sativus L.), and turnip cv. Pointer showed more than 50% population reduction compared with initial population densitiy, consistently in the greenhouse or microplot experiments. The resistance screening of 152 early-maturing soybean accessions showed that a majority of the accessions were susceptible/moderately susceptible to both SCN populations (SCN HG type 0 and 2.5.7), while a few (n=18) showed good resistance responses to both or either of the SCN populations. The cover crops, which were non-hosts/poor-hosts and have a greater ability for the SCN population reduction have great potential to be included in an integrated SCN management strategy. The novel resistant accessions identified in this study have the potential to be used in soybean breeding for developing SCN-resistant cultivars after confirming their resistance response and identifying the resistance genes/loci. The results obtained from this study helps in developing a sustainable SCN management strategy in the northern Great Plains.

Made available in DSpace on 2016-01-26T18:56:22Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 291613 bytes, checksum: 351209f8c0af1b2f460925dd83ce0a2d (MD5) Previous issue date: 2010-11-17
Soybean is considered the main crop in Brazil due to both volume production and income. Many factors have contributed to a good performance of this crop in this country, such as adaptability of cultivars to many regions. The objective of this research was to evaluate soybean performance of early, semi-early and intermediate maturity cultivars in a sandy loam, clayey and very clayey Eutrudox. The experiment was carried out in Naviraí, Mato Grosso do Sul, Brazil, São Francisco Farm, in 2008/2009. The experimental design was the completely randomized block with four replications. The following soybean cultivars were evaluated: a) Early maturity: CD 202, CD 208 and CD 214RR; b) Semi early maturity: BRS 239, BRS CharruaRR and BRS 245RR; and c) Intermediate maturity: CD 219RR and Monsoy 8001. Sowing was conducted over maize residues on November, 15th, 2008 under no tillage system and 333 kg ha-1 of fertilizer was applied. The number of pods per plant, number of grains per pod, weight of 1,000 grains and yield (kg ha-1) were evaluated. Fertilization and maintenance of intermediate-high nutrient levels in Eutrudox soils of any textures provides conditions for soybean cultivars to express high yield potentials.
A soja é a principal cultura do País tanto em volume como em geração de renda, sendo que vários fatores tem contribuído para esse bom desempenho no Brasil, dentre eles podemos citar a adaptabilidade de cultivares ás diferentes regiões produtoras. O objetivo deste trabalho foi de avaliar o desempenho de cultivares de soja dos ciclos precoce, semiprecoce e médio em Latossolos Vermelhos com diferentes classes texturais. Latossolo Vermelho Eutrófico textura média, Latossolo Vermelho Eutrófico textura argilosa e Latossolo Vermelho Eutrófico textura muito argilosa. O experimento foi conduzido no município de Naviraí Estado de Mato Grosso do Sul, na Fazenda São Francisco, na safra agrícola 2008/2009. O delineamento experimental foi de blocos inteiramente casualisados com quatro repetições. Os cultivares de soja utilizados foram: a) Ciclo precoce: CD 202, CD 208 e CD 214RR; b) Ciclo semiprecoce: BRS 239, BRS CharruaRR, BRS 245RR e c) Ciclo médio: CD 219RR e Monsoy 8001. Em todos os solos o plantio ocorreu no dia 15 de novembro de 2008, em sistema de plantio direto sobre a resteva de milho com adubação de 333 kg ha-1. Foram avaliados os parâmetros de número de vagens por planta, número de grãos por vagens, peso de mil grãos e calculado produtividade em quilogramas por hectare. Independente da classe textural, a fertilização e manutenção de médios a altos teores de nutrientes nos LATOSSOLOS VERMELHOS Eutróficos de textura média a muito argilosa possibilita a expressão fenotípica de altas produtividades agrícolas de grãos pelas cultivares de soja.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009.
Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3290. Adviser: Lila O. Vodkin. Includes bibliographical references (leaves 159-165) Available on microfilm from Pro Quest Information and Learning.