Spiderwort (Tradescantia virginiana) is a flowering herbaceous perennial. Little information is available about its production requirements. This project’s purpose was to determine fertilizer and PGR rates for high quality growth of Spiderwort in a greenhouse production setting. The first experiment screened three plant growth regulators (PGRs) at ascending rates on three T. virginiana cultivars. The most effective rates for height suppression were paclobutrazol at 120 mgּL-1, uniconazole at 45 mgּL-1, and flurprimidol at 45 mgּL-1. The second experiment was divided into two parts. The first screened three T. virginiana cultivars for their growth response to several nitrogen (N) rates. The second experiment used results from the first experiment and examined two cultivars response to a basic fertilizer. For experiment 1, N rates between 100 and 200 mg‧L-1 resulted in quality plant growth. The second experiment showed little difference between height, width and flowering of both cultivars with these N rates. Plant quality was similar for plants fertilized with 100 and 200 mgּL-1 N at the end of both experiments. The third study examined how fertilization rate affects the persistence of PGR growth control. PGR rates identified as effective in experiment 1 were used. Plants fertilized with 200 mgּL-1 N were taller than those fertilized with 100 mgּL-1 N, regardless of PGR treatment. PGRs did not suppress plant growth; plant quality was similar regardless of treatment. The results of these studies indicate that PGR effectiveness in suppressing plant height may be dependent upon season, with PGR application necessary only during the spring growing season. / Master of Science

Little information is available about greenhouse production requirements of <i>Phlox paniculata</i> 'Blue Boy' and <i>Rudbeckia hirta</i> 'Indian Summer', both of which are extremely susceptible to powdery mildew. Some plant growth regulators (PGRs) have been reported to reduce severity of certain plant diseases. The objectives of these experiments were to: 1) define optimal fertilizer, irrigation rates, and media types for these cultivars; 2) determine optimal PGR rates for size control; and 3) determine effects of PGRs on powdery mildew severity on inoculated plants grown under optimal greenhouse conditons. When looking at the variables height, average width, quality rating, and shoot dry weight, <i>Phlox paniculata</i> 'Blue Boy' grew best at 200 mg·L⁻¹ N in Fafard 3B medium and was not responsive to irrigation rate. Also, when looking at the same variables mentioned above, <i>Rudbeckia hirta</i> 'Indian Summer' grew best at 300 mg·L⁻¹ N in Scott's Sierra Perennial Mix at a high irrigation rate. The PGRs chlormequat chloride, daminozide/chlormequat chloride, and paclobutrazol were effective in controlling size of <i>Phlox</i>. During the first <i>Rudbeckia</i> experiment, paclobutrazol and uniconazole were effective in controlling plant size; in the second experiment daminozide, uniconazole and flurprimidol were effective. In the fall experiment, 160 mg·L⁻¹ paclobutrazol was effective in reducing disease severity in Phlox; in the spring experiment, 4000 mg·L⁻¹ chlormequat chloride and 60 mg·L⁻¹ uniconazole were effective in reducing disease severity. In the <i>Rudbeckia</i> fall experiment, 160 mg·L⁻¹ of two forms of paclobutrazol were effective in reducing disease severity; in the spring experiment, only one of those forms (Bonzi) was effective. / Master of Science

Embora o Brasil apresente grande potencial para a expansão da cultura do abacateiro, sobretudo devido as condições edafoclimáticas favoráveis, sua produção ainda é restrita no país, principalmente devido a fatores limitantes, como a não adoção do adensamento nos pomares comerciais e de manejos agronômicos que favoreçam a produção e qualidade de frutos; a presença de Phytophthora cinnamomi, principal patógeno que afeta a cultura em todo o mundo; o fato da grande maioria dos pomares comerciais serem cultivados sob condições de sequeiro; e devido a fatores inerentes a ecofisiologia da planta, como vigor excessivo, baixa fixação de frutos e a dificuldade em controlar a alternância de produção. A aplicação de fitorreguladores é um manejo importante e com bons resultados, nos pomares comerciais dos principais países produtores, sendo esta uma técnica que visa melhorar a produtividade, incrementar o tamanho dos frutos, diminuir a alternância produtiva e reduzir o vigor vegetativo. O objetivo desta pesquisa foi avaliar o efeito de distintos fitorreguladores no desenvolvimento vegetativo, produção, eficiência e alternância produtiva, tamanho e formato de frutos e na qualidade pós-colheita de abacateiros \'Hass\' não irrigados. Entre 2013 e 2016, foram avaliados sete tratamentos via pulverização foliar: T1: água (testemunha); T2: 250 mg.L-1 Viviful&reg; (68,75 mg.L-1 prohexadione-cálcio); T3: 0,7% Cultar&reg; 250 SC (0,175% paclobutrazol); T4: 0,7% Sunny&reg; (0,035% uniconazole); T5: 1% Moddus&reg; (0,25% etil-trinexapac); T6: 1250 mg.L-1 MaxCel&reg; (25 mg.L-1 6- benziladenina) aplicados no florescimento; e T7: 125 mg.L-1 ProGibb&reg; 400 (50 mg.L-1 ácido giberélico) aplicado no início do mês de dezembro antes da segunda queda natural de frutos. O delineamento experimental foi conduzido em blocos ao acaso, com 7 tratamentos, 4 repetições e 2 plantas por parcela. Nos distintos tratamentos foram avaliados: tamanho da planta; crescimento dos brotos de primavera; produção, tamanho e formato de frutos e a qualidade pós-colheita. Os fitorreguladores utilizados não afetaram significativamente o desenvolvimento vegetativo, a eficiência produtiva e a produção de frutos, bem como não influenciaram na qualidade pós-colheita dos mesmos. O inibidor de giberelina uniconazole (T4) foi o responsável por reduzir significativamente o crescimento dos brotos de primavera durante os três anos de avaliações. A citocinina 6-benziladenina (T6) reduziu de forma significativa a alternância produtiva de abacateiros \'Hass\' enquanto o uniconazole (T4), prohexadione-cálcio (T2) e 6-benziladenina (T6) aumentaram significativamente o tamanho dos frutos. A maioria dos fitorreguladores utilizados modificaram o formato dos frutos, tornando-os mais arredondados, com destaque para o efeito do etil-trinexapac (T5). A aplicação dos distintos fitorreguladores se apresentam inconstantes ao longo dos anos de pesquisa e não afetam número, produção de frutos (Kg.planta-1) e eficiência produtiva de abacateiros \'Hass\' não irrigados. / Although Brazil presents great potential for the expansion of the avocado crop, especially due to the favorable edaphoclimatic conditions, its production is still restricted in the country, mainly due to limiting factors, such as the non-adoption of high-density plantings in commercial orchards and agronomic managements to support high fruit yield and quality; the presence of Phytophthora cinnamomi, the main pathogen affecting avocados around the world; the fact that most of the commercial orchards are grown under rainfed conditions; and also due to factors that are inherent to the tree\'s ecophysiology, such as the excessive vigor, low fruit set and difficulty in controlling the alternate bearing. Plant growth regulators (PGRs) have become important management tools in the commercial orchards of the main producer countries for improving yields, increasing fruit size, reducing alternate bearing and reducing vegetative vigor. The aim of this research was to evaluate the effect of different PGRs on vegetative growth, fruit yield, yield efficiency and alternate bearing, fruit size and shape, and post-harvest quality of \'Hass\' avocados non-irrigated. Between 2013 and 2016, seven treatments were evaluated by foliar sprays : T1: water (control); T2: 250 mg.L-1 Viviful&reg; (68,75 mg.L-1 prohexadione-calcium); T3: 0,7% Cultar&reg; 250 SC (0,175% paclobutrazol); T4: 0,7% Sunny&reg; (0,035% uniconazole); T5: 1% Moddus&reg; (0,25% trinexapac-ethyl); T6: 1250 mg.L-1 MaxCel&reg; (25 mg.L-1 6-benzyladenine) all applied in full bloom; and T7: 125 mg.L-1 ProGibb&reg; 400 (50 mg.L-1 gibberelic acid) applied at the beginning of December, before the second natural fruit drop. The experiment was conducted in a randomized block design with seven treatments, four replications and two plants per plot. The following variables were evaluated: tree size, spring shoot growth, fruit yield, size and shape and post-harvest fruit quality. The applied PGRs did not significantly affect tree size, yield efficiency and fruit yield, nor did they influence the post-harvest fruit quality. Uniconazole (T4) was responsible of a significant shortening of spring shoots during the three years of evaluations. The cytokinin 6-benzyladenine (T6) significantly reduced alternate bearing of \'Hass\' avocado trees. Spring sprays of uniconazole (T4), prohexadione-calcium (T2) and 6-benzyladenine (T6) significantly increased fruit size. Most of the PGRs modified -fruit shape of \'Hass\' avocados to a more rounded format, with trinexapac-ethyl (T5) showing a stronger effect. The application of the different PGRs are inconsistent throughout the years of research and do not affect fruit number and yield (kg.tree-1) and yield efficiency of non-irrigated \'Hass\' avocados.