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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The influence of mineral nutrition, stage of harvest and flower position on seed yield and quality of Phaseolus vulgaris L

Gavras, Michael F. January 1981 (has links)
In this work the effects of mother plant nutrition and flower position on the plant in relation to different harvest stages on French beans (Phaseolus vulgaris L. cv. Cascade); seed yield, quality and progeny performance have been studied. In three pot experiments under glass and one in the field, different levels of nitrogen, phosphorus, potassium and molybdenum were applied to the mother plant and it was found that higher seed yields were obtained with the higher nutrient levels tested, but these high seed yields were not necessarily accompanied by high quality. Seed yield and quality increased with the increase of nitrogen and potassium. The phosphorus effect however, was different, in that the seed yield increased in relation to the levels but the seed quality decreased. Molybdenum was found to be necessary in moderate amounts, especially for the seed quality. The interactions between nitrogen and phosphorus levels (NP) and between nitrogen, phosphorus and potassium (NPK) were found to be very important for bean seed quality, because their significant effect was similar and constantly present in most of the seed vigour components examined. It seems that the combinations of high nitrogen levels with moderate amounts of phosphorus applied to the mother plant resulted in seed of good quality. In one pot experiment under glass the progeny performance was examined, using seed from the 1st mother plant nutrition experiment and it was found that the mother plant nutrition affected the progeny in it's early stages. This effect disappeared later and no difference in progeny seed yield was found. In two pot experiments under glass the bean pods were harvested at different stages and the pods from the main axis were separated from the pods on the secondary branches grown mainly from the axils of the primary leaves. It was found that the quality of seed from the secondary branches was lower than the quality of seed from the main axis. However, this difference in seed quality became less with the later harvests. The following tests were used to assess seed quality: the official germination test, seedling evaluation test, cold test, and electrical conductivity test. In addition, the seed size was determined and the seeds were analysed for total nitrogen, phosphorus and potassium content.
2

Superoptimal CO2 Reduces Seed Yield in Wheat

Grotenhuis, Timothy P. 01 May 1996 (has links)
Although projected terrestrial CO2 levels will not reach 1000 μmol moI-1 (0.1%) for many decades, CO2 levels in growth chambers and greenhouses routinely exceed that concentration. CO2 levels in life support systems in space can exceed 10,000 μmol moI-1 (1%) CO2. Numerous studies have examined CO2 effects up to 1000 μmol mol-1, but theoretical and some experimental evidence indicates that the beneficial effects of CO2 continue past 1000 μmol mol-1 and are near-optimal for wheat at about 1200 μmol mol-1. We studied the effects of near-optimal and superoptimal CO2 levels (>1200 μmol mol-1) on yield of two cultivars of hydroponically grown wheat in 12 trials. Increasing CO2 from suboptimal to near-optimal (350 to 1200 μmol mol-1) increased vegetative growth by 25% and seed yield by 15% in both cultivars. Yield increases were primarily the result of an increased number of heads m-2. Further elevation of CO2 to 2500 μmol mol-1reduced seed yield by 22% in cv. 'Veery-10' and by 15% in cv. 'USU-Apogee'. Superoptimal CO2 did not decrease the number of heads m-2, but reduced seeds per head by 10% and mass per seed by 11%. CO2 toxicity occurred over a wide range of light levels. Subsequent trials revealed that superoptimal CO2 in the 2 weeks before and after anthesis mimicked the effect of constant superoptimal CO2. Furthermore, near-optimal CO2 in the 2 weeks before and after anthesis mimicked the effect of constant near-optimal CO2. Nutrient concentration of leaves and heads was not affected by CO2. The yield decreases may be a response mediated by ethylene.
3

Characterization of physiological parameters in soybean with genetic improvement in seed yield

Keep, Nathan R. January 1900 (has links)
Master of Science / Department of Agronomy / William T. Schapaugh / Recent results from a genetic gain study have illustrated the contribution of plant breeding to the improvement in seed yield of soybean (Glycine max (L.) Merr.). The objective of this research was to characterize the changes in several physiological parameters that have occurred in the released cultivars with improvement of seed yield. Sixty maturity group III and 54 maturity group IV cultivars, released from the 1920's through 2010, were evaluated in dryland and irrigated environments at Manhattan, KS in 2010 and 2011. Genotypes were planted in four-row plots, 3.4 m long, spaced 76 cm apart, arranged in a randomized complete block design with four replications. Genotypes were evaluated for canopy temperature, leaf chlorophyll content, pollen germination, leaf chlorophyll fluorescence, leaf antioxidants, and yield components. Canopy temperature measurements were captured between 1000h and 1400h using an infrared camera multiple times from R1 continuing through R6. Leaf chlorophyll content was measured using a SPAD meter several times from R1 through R6. In vitro pollen germination was measured using incubation temperatures of 28 and 34° C, beginning at late R1 through the end of flowering. Leaf chlorophyll fluorescence was measured beginning at R1 through R6. Leaf antioxidants were analyzed for total antioxidant capacity and electrolyte leakage by collecting leaves from the top 3rd to 5th trifoliate at R4 and R6. Yield components were analyzed from a hand harvested 0.33 m section of one border row. Genotypes differed significantly for canopy temperature, leaf chlorophyll content, pollen germination, and yield components. No significant differences were found for leaf chlorophyll fluorescence or leaf antioxidants. Seed yield increased with year of release. Canopy temperature was negatively correlated and leaf chlorophyll content was positively correlated with year of release in both maturity groups. No significant correlation with year of release was found for in vitro pollen germination or electrolyte leakage. Leaf chlorophyll fluorescence, yield components, and total antioxidant capacity was positively correlated in the maturity group IV genotypes with year of release. Evaluation of these parameters may serve as a basis to select for seed yield, or to assess the abiotic stress tolerance of a genotype.
4

Effects of Increased Temperature on Growth and Seed Production of Soybean / ダイズの生長および子実生産に及ぼす温度上昇の影響

Custodio Ramos Paulo Tacarindua 25 November 2013 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第17964号 / 農博第2032号 / 新制||農||1019(附属図書館) / 学位論文||H25||N4808(農学部図書室) / 30794 / 京都大学大学院農学研究科農学専攻 / (主査)教授 白岩 立彦, 教授 奥本 裕, 教授 稲村 達也 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
5

Temperature effects on soybean vegetative, physiological, reproductive growth and development, and seed yield and quality

Alsajri, Firas Ahmed 14 December 2018 (has links)
Temperature is a major factor affecting plant growth and development at all stages. The objectives of this study were to investigate the temperature effects on all aspects of soybean growth and development. Five experiments were conducted at a wide range of temperatures under optimum water and nutrient conditions at specific growth stages. Two cultivars, Asgrow AG5332 (AG) and Progeny P5333RY (PR) from MG V with different growth habits, were used. All studies except the seed germination were conducted in sunlit plant growth chambers under optimum water and nutrient conditions. The seed germination experiment was conducted in a temperature-controlled incubator. Germination traits were measured during seed germination studies. In other experiments, plant growth, developmental rates, gas exchange parameters, and seed yield and quality were measured. Cultivars did not differ for seed germination and emergence traits. Quadratic functions best described time to 50% germination seed germination and emergence rates. The three cardinal temperatures for seed germination were 8.56°C (base) 27. 96°C (optimum) and 46.92°C (maximum). The base and optimum temperature for seed emergence were 10.6 and 36.7°C, respectively. During the early-season, 0-21 days, root and shoot growth parameters responded similar temperature responses, the root traits have a lower optimum (29.91°C) than the shoot parameters (36.56°C). Cultivars varied in their response to temperature during vegetative development, particularly for growth parameters, and the temperature optimums for various parameters. Node addition rate was not different among the cultivars but increased with increase in temperature. The flowering time (R1) from emergence showed quadratic trends with an increase in temperature up to 28°C and increased slightly at the higher temperatures. The PR cultivar, on an average, took 15 additional days to reach flowering compared AG cultivar across temperatures. Pod and seed yield and individual seed weight and harvest indices showed quadratic trends with maximum values at 25.82 °C for AG and 23.36 °C for PR. The functional algorithms could be helpful for management and in improving crop models.
6

Cultural Thinning of Native Sagebrush Stands to Increase Seed Yields

Elder, Kurt David 13 December 2012 (has links) (PDF)
Wyoming big sagebrush (Artemisia tridentata Nutt.) is an important native shrub in the Great Basin because of its wide distribution where it dominates over 60 million ha and provides essential habitat and forage for many varied species. The hand collection of sagebrush seed often results in seed scarcity and the available seed quantities are at times inadequate to revegetate large areas that have been disturbed, resulting in a demand for sagebrush seed. Study locations were selected near Scipio and Sahara sand dunes of Utah, and treatments were 1-) control, no treatment applied area left undisturbed 2-) general chemical strip thinning 3-) general chemical thinning of entire stand, 4-) general mechanical strip thinning, and 5-) general mechanical thinning of the entire stand. Significant differences among treatments in seed yields were collected in 2011 at Scipio but not at Sahara. At Scipio, the mechanical strip of competing sagebrush in 3m strips was the most effective of all treatment and produced 2.47kg/ha compared to 4.624kg/ha in the control, but the mechanical land area was only utilizing half the compared control area. The chemical treatments produced 1.819kg/ha and 1.31kg/ha. The percent of sagebrush mortality by each treatment determined the level of competition killed in treatment areas. All treatments at both locations killed at least 57% of the sagebrush. Chemical treatments had a consistent kill rate at both locations, although lower than anticipated, but mechanical kill was the highest at 93% in Scipio. Both mechanical and chemical treated plots had increased cover levels of cheatgrass when compared to the control plots.
7

Hodnocení výnosu a výnosových prvků vybraných odrůd sóji luštinaté (Glycine max (L.) Merrill.) v oblasti s méně příznivými podmínkami / Evaluation of seed yield and yield components in selected soya (\kur{Glycine max} (L.) Merrill.) cultivars in region with less favourable conditions

VŠETEČKA, Petr January 2019 (has links)
The aim of this master thesis was the finding out of potential of growing the soybeans in the area with not so suitable growing conditions. The next aim was to perform the experiment with application of leaf fertilizer EGT Fulhum which increases root system volume. In the years 2016 and 2017 was in the altitude 395 m established the field experiment with the variety Amandine and since the year 2017 was also joint the experiment with the very early variety Abeline. Within these cultivars of soybean were evaluated these parameters: Seed yield, the 1000 seed weight, seed oiliness, plant height, number of pods on one plant, number of the early branches and weight of roots. The seed yield was very variable from the point of view of the year. The yield in the year 2016 was above-average, the control variant reached the yield 2,93 tons per hectare and variant treated by Fulhum 2, 78 tons per hectare. One of the studied parameter was the nitrogen content and based on the results of this parameter was noticeable reduction of nitrogen content of the treated variant in the comparison with control variant. In the further year were two compared two varieties - Amandine and Abeline. Within the both varieties were involved to the experiment the control variant and the variant treated by plant auxiliary substance. In the year 2017 was confirmed the influence of the crop area establishment on the yield quality parameters. The progress of weather confirmed the high requirements of soybean on the good rainfall conditions. Seed yield of the variety Amandine was 1,07 tons per hectare in the case of the treated variant, by control variant it was 0,88 tons per hectare. The difference of the seed yield between both variants of the variety Abeline was very little, it was 0,90 tons per hectare by the treated variant and 0,93 tons per hectare by the control variant. The application of the plant auxiliary substance didn't cause, on average, the improvement of the studied parameters so the using of this substance, for the improvement of these parameters almost doesn't make any sense.
8

Determinants of seed size and yield in Arabidopsis thaliana

Hughes, Rhiannon January 2009 (has links)
It is becoming increasingly important to improve the yield of seed crops to feed an expanding population and, more recently, to cope with additional strains on food-oriented agriculture posed by biofuel production and global climate change. One strategy to increase yield is to increase seed size. However in nature, due to the limited resources of the mother plant, an enlarged seed size is often associated with a concomitant reduction in seed number. Using the model plant Arabidopsis thaliana, a biotechnological approach to increase seed size through the modification of the triploid endosperm or the ovule integuments was shown to be a viable strategy to improve seed yield. Targeted over-expression of the ANT transcription factor specifically within the endosperm significantly increased seed size without negative effects on fertility. Overcoming compromised fertility in arf2 mutants established that ARF2 and the integuments are important factors in determining seed size and yield. To ensure agronomic relevance, both the gross yield and the harvest index (HI, ratio of seed yield to biological yield) were used to assess the impact of traits, such as increased integument size, introduced into Arabidopsis. To uncover novel regulators of seed size and further develop the current understanding of seed development, second-site mutations were induced in the auxin response factor 2 (arf2) mutant, which produces large seeds due to extra cell division in the ovule integuments. The ARABIDOPSIS CRINKLY 4 (ACR4) gene was identified as a suppressor of the arf2 seed phenotype. In arf2-8 acr4 double mutants, an additive effect on cell proliferation was observed, indicating that ACR4 affects the seed coat through a developmental pathway independent of ARF2. Natural variation present in Arabidopsis was used to study seed yield and its components. Considerable variation in seed size, yield and HI was revealed. Significantly, high seed weight was not associated with high yield or high HI. In contrast, high seed number and reduced plant stature were revealed as important components of high yield and yield efficiency. Additionally, ERECTA was identified as a potential ‘Green Revolution’ gene. Seed size in Arabidopsis was shown to be an extremely plastic trait in response to alterations in the post-flowering source-sink ratio, increasing by 35.0 – 66.2% in the ecotypes tested. Furthermore, a difference in seed weight between restricted (high source-sink ratio) and unrestricted (low source-sink ratio) pollinations was first observed remarkably early in seed development. However, reducing seed number by restricting pollination did not substantially alter integument or endosperm development in order to facilitate increased nutrient uptake.
9

Effect of seed-placed phosphorus and sulphur fertilizers on canola plant stand, early season biomass and seed yield

Grenkow, Laryssa 10 September 2013 (has links)
Seed-placed phosphorus (P) and sulphur (S) fertilizers can reduce canola plant stands. Field studies were conducted to determine the effect of various sources and rates of seed-placed P and S fertilizers on canola plant stand, early season biomass accumulation and seed yield. Conventional granular P and S blends increased the risk of seedling damage, but increased the frequency of yield response. Liquid fertilizers were similar in seedling damage but generally less effective in increasing seed yield compared to granular fertilizers. Novel fertilizers were more seed-safe but less reliable than conventional sources in increasing seed yield. A growth room experiment was conducted to determine the effect of soils from different landscape positions on the toxicity of seed-placed ammonium sulphate (AS) and monoammonium phosphate (MAP). Canola emergence was reduced and delayed by seed-placed MAP and AS. Ammonium sulphate in particular has a high risk of NH3 toxicity on calcareous hilltop soils
10

Effect of seed-placed phosphorus and sulphur fertilizers on canola plant stand, early season biomass and seed yield

Grenkow, Laryssa 10 September 2013 (has links)
Seed-placed phosphorus (P) and sulphur (S) fertilizers can reduce canola plant stands. Field studies were conducted to determine the effect of various sources and rates of seed-placed P and S fertilizers on canola plant stand, early season biomass accumulation and seed yield. Conventional granular P and S blends increased the risk of seedling damage, but increased the frequency of yield response. Liquid fertilizers were similar in seedling damage but generally less effective in increasing seed yield compared to granular fertilizers. Novel fertilizers were more seed-safe but less reliable than conventional sources in increasing seed yield. A growth room experiment was conducted to determine the effect of soils from different landscape positions on the toxicity of seed-placed ammonium sulphate (AS) and monoammonium phosphate (MAP). Canola emergence was reduced and delayed by seed-placed MAP and AS. Ammonium sulphate in particular has a high risk of NH3 toxicity on calcareous hilltop soils

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