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Studies were conducted in small-plot and onarm environments in Mississippi in 2018 and 2019 to determine the effect of prohexadione calcium growth regulator on the growth and yield of peanut [Arachis hypogaea (L.)]. Onarm trials conducted in 2018 and 2019 concluded that in situations where the application of prohexadione calcium increased yield, variation in application rate had no effect on yield. Yields of peanut where any rate of prohexadione calcium was applied were 415 kg ha-1 greater than yields of peanut where prohexadione calcium were not applied. The addition of other agrichemicals had no effect on the efficacy of prohexadione calcium. Small-plot research in 2019 concluded that no rate variation had any effect on the growth or yield of peanut, and also concluded that alternative application timing methods had no effect on yield or growth of peanut.

Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-24Bitstream added on 2014-06-13T20:34:24Z : No. of bitstreams: 1 takata_whs_me_botfca.pdf: 422211 bytes, checksum: 5af12fb97f188348230baf5f4a2c8a89 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O mercado de frutas exóticas no Brasil tem ganhado prestígio e o cultivo da pitaya apresenta-se promissor. Porém, o seu ciclo é limitado ao longo do ano, principalmente, pela influência do fotoperíodo no seu florescimento. A utilização de regulador vegetal, sobretudo a giberelina (GA), pode substituir a necessidade de dias longos. Nesse sentido se estudou diferentes épocas de aplicação e várias concentrações de GA3 no período não indutivo com o objetivo de induzir e antecipar o florescimento. O delineamento experimental utilizado foi blocos ao acaso em esquema fatorial 3x5, sendo três épocas de aplicação e cinco concentrações do regulador vegetal. As épocas de aplicação iniciaram em maio, junho e julho, sendo realizadas três aplicações a cada 30 dias. As concentrações estudadas foram 0, 100, 200, 300 e 400 mg L-1 de GA3. A época de aplicação de GA3 não influenciou em nenhuma das características estudadas, por outro lado o fator concentração, apesar de não ter antecipado o florescimento, proporcionou aumento na fixação de frutos, número de frutos, massa média de frutos e produtividade. Com base nos resultados obtidos é possível concluir que a aplicação de GA3 foi benéfica às características agronômicas da pitaya / The exotic fruit market in Brazil has gained prestige and cultivation of pitaya presents promising. But the cycle is limited throughout the year, and its flowering by photoperiod. The use of plant growth regulator, especially gibberellins, can replace the need for long days, in this sense, we studied different application periods and some concentrations of GA in non-inductive period in order to anticipate flowering. The experimental design was randomized blocks in factorial scheme 3x5, being three times of application and five concentrations of the GA3. The application periods began in May, June and July, and three times application, one every 30 days. The concentrations studied were 0, 100, 200, 300 and 400 mg L-1 GA3 application timing did not influence any of the traits on the other hand the concentration factor, despite not having anticipated the flowering could provide increased fruit set, fruit number, mean fruit mass and productivity. Based on the results, we concluded that the GA3 application was beneficial to the agronomic characteristics of pitaya

Made available in DSpace on 2014-06-11T19:33:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-18Bitstream added on 2014-06-13T19:44:33Z : No. of bitstreams: 1 justi_mm_dr_jabo.pdf: 497881 bytes, checksum: 84f3db860aba3b676cb265a4612b41d8 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Com o objetivo de avaliar o efeito de doses de cloreto de mepiquat em cultivares de algodão herbáceo, foi conduzido um experimento no ano agrícola de 2002/2003, na Fazenda de Ensino e Pesquisa da FEIS/UNESP, localizada no município de Selvíria (MS). O delineamento experimental utilizado foi o de blocos ao acaso, com parcelas subdivididas, e quatro repetições. Nas parcelas foram estudados quatro cultivares de algodão (Coodetec 401, IAC 24, DeltaOpal e Deltapine Acala 90) e nas subparcelas, três doses de cloreto de mepiquat (0,0; 50,0 e 100,0 g i.a.ha-1). As parcelas experimentais constituíram-se de seis linhas com 10 m de comprimento e 0,90 m de espaçamento entrelinhas, sendo consideradas úteis as quatro linhas centrais. Foram determinados, em dez plantas de cada parcela, a altura das plantas e o diâmetro do caule. O número de nós no caule, número de ramos e de capulhos por planta foi obtido em cinco plantas amostradas de cada parcela. A produção de algodão em caroço foi determinada através da colheita dos capulhos em quatro metros de cada uma das duas linhas centrais. Amostras de 20 capulhos de cada parcela foram utilizadas para a obtenção da massa média de um capulho, massa de 100 sementes, porcentagem de fibra e características tecnológicas da fibra. A análise de crescimento foi feita determinando-se, a cada 14 dias, a área foliar e a massa seca acumulada nos diferentes órgãos da planta. A partir desses dados foram calculados a área foliar total, razão de área foliar, área foliar específica, razão de massa de folhas, taxa de crescimento relativo e taxa assimilatória líquida. Considerando-se 100% a massa seca total, determinou-se a distribuição em porcentagem da massa seca entre as diferentes estruturas da planta... / The experiment was conducted with the objective of evaluating the effect of doses of mepiquat chloride in cotton cultivars in the agricultural year of 2002/2003, at Teaching and Research Farm of FEIS/UNESP, located in Selvíria, MS, Brazil. The experimental design was complete blocks in split-plot arrangement and four replications. In the plots four cotton cultivars (Coodetec 401, IAC 24, DeltaOpal and Deltapine Acala 90) were studied and in the subplots, three doses of mepiquat chloride (0,0; 50,0 and 100,0 g i.a.ha-1). The experimental plots had six rows with 10 m of length and 0,90 m between rows, being considered useful the central four rows. The height of the plants and the diameter of the stem were measured in ten plants in each plot. The number of nodes in the stem, number of branches and of fruits per plant were obtained in five plants collected from each plot. The cotton yield was determined through the harvested fruits of the two central rows. Samples of 20 fruits of each plot were used to obtain the average mass of one fruit, mass of 100 seeds, fiber percentage and technological characteristics of the fiber. The growth analysis was performed by determining, every 14 days, the leaf area and the dry mass accumulated in the different organs of the plant. From those data, total leaf area, leaf area ratio, specific leaf area, ratio of leaf mass, relative growth rate and net assimilation rate, were calculated. Considering the total dry mass as 100%, the distribution, in percentage, of the dry mass among the different structures of the plant was determined. The obtained results allowed to conclude that 50,0 g i.a.ha-1 of mepiquat chloride caused minor height of the plants in the Coodetec 401, DeltaOpal and Deltapine Acala 90 cultivars while, for 24 IAC the dose of 100,0 g i.a.ha-1 was the best... (Complete abstract, click eletronic address below)

Field, greenhouse and laboratory experiments were implemented to investigate the effects of auxin herbicides on growth and yield of cotton in glyphosate based systems. Field experiments evaluated the effect of rate and timing of dicamba or 2,4-D exposure when applied in glyphosate-resistant cotton. Increasing rates of either dicamba or 2,4-D resulted in increased injury and yield reductions. Initial injury symptomology was similar for cotton exposed at vegetative and reproductive stages. When cotton was exposed to auxin herbicides during vegetative growth, injury increased with time, while foliar injury during reproductive growth was stagnant and often decreased with time. Subsequently, the strongest correlations to yield loss and injury were from later evaluations of vegetative timings. Recovery from injury due to auxin herbicide exposure was dependent upon favorable environmental conditions; however, recovery was often superficial and masked significant yield loss. Greenhouse studies evaluated the impact of the diglycolamine dicamba salt on the movement of 14C radio-labeled potassium salt glyphosate in barnyardgrass and johnsongrass. Increasing glyphosate rate increased total absorption of glyphosate in both species. Total absorption of glyphosate was not impacted by the presence of dicamba, for either johnsongrass or barnyardgrass. Dicamba did not consistently alter the translocation of glyphosate in johnsongrass; however, dicamba did reduce glyphosate translocation in barnyardgrass. Total amount of translocated glyphosate was 2.6 to 4.6% and 3.8 to 6.8% of applied in barnyardgrass and johnsongrass, respectively. Reduced translocation in barnyardgrass was a result of increased glyphosate accumulation in the distal portion of the treated leaf. Increasing the rate of glyphosate did overcome the dicamba induced antagonism; however, altered translocation of glyphosate has been documented to be a precursor to herbicide resistance.

Studies were conducted to evaluate the effects of trinexapac-ethyl (TE) on height reduction, tillering, chlorophyll content, color, flowering, and root development of three ornamental grasses: Calamagrostis ×acutiflora 'Karl Foerster', Miscanthus sinensis 'Variegatus', and Pennisetum ×advena 'Rubrum'. Two applications of TE reduced height in all grasses and improved chlorophyll content in C. 'Karl Foerster' while delaying flowering in M. 'Variegatus' and P. 'Rubrum'. Tillering was slightly increased in M. 'Variegatus' with two TE applications. Shoot dry weight (SDW) and root dry weight (RDW) were reduced in C. 'Karl Foerster', SDW was reduced in P. 'Rubrum' and SDW and RDW were unaffected by applications of TE in M. 'Variegatus'. TE is effective for growth control in ornamental grass production systems; however, the results are species specific and should be tested further before widespread use on other ornamental grass species.

Studies were conducted in the field from 2020-2021 in peanut and cotton to optimize peanut growth and yield through prohexadione calcium application methods as well as weed control through increasing herbicide sites of action. These studies were established on multiple on-farm and small-plot locations in Mississippi. Prohexadione calcium studies concluded that following application of prohexadione calcium effects on yield and peanut growth were inconsistent. Neither varying application timing nor rate resulted in peanut yield that was different than when adhering to the label recommendations. Increasing sites of action studies concluded that broadleaf signalgrass and Amaranthus species control was optimized at four SOAs and two SOAs, respectively. Based on this study, the current recommendation of additional SOAs will not result in increased weed control.

Efforts to implement integrated pest management (IPM) strategies and improving our understanding of existing strategies are keys to achieving adequate control of tarnished plant bug, Lygus lineolaris. Insecticide applications are a part of IPM and monitoring their efficacy is critical for producers to remain profitable. Resistance to imidacloprid, thiamethoxam, and sulfoxaflor was documented, although there continues to remain variability among populations within the region. The insect growth regulator, novaluron, although only lethal to nymphs, plays an important role in management of Lygus. Sublethal impacts to adult plant bugs may be an important factor in reducing populations within the growing season. Future research to confirm the validity of using a laboratory colony as a baseline for insecticide susceptibility is needed to account for increased vigor of insects reared on artificial diet.

Flower forcing to meet holiday market can increase the value of potted flowering plants. This study was to investigate the effects of chilling and post-chilling photoperiod treatments on flowering of banana shrub and the effects of water stress, daminozide, chlormequat, and ethephon on flowering of bougainvillea. Experiments were conducted at R.R. Foil Plant Science Research Center and MSU Dorman Greenhouse at Mississippi State University (MSU), Mississippi State, MS. Results from banana shrub experiment indicated that 8-week chilling at 8 ºC was necessary for banana shrub to break bud dormancy and a tank mix of daminozide and chlormequat was able to increase the number of flower buds on banana shrub. Results from bougainvillea experiment indicated that water stress, daminozide, and chlormequat enhanced flowering. In conclusion, this study provided fundamental information to future research on flower forcing of banana shrub and bougainvillea.