Weed control and desiccation are routinely executed with herbicides. Potato vine desiccation facilitates harvest, improves skin set, and regulates tuber size. Saflufenacil, glufosinate, saflufenacil plus glufosinate, and carfentrazone plus glufosinate were compared to diquat applied at 43, 31, and 17% B potatoes; similar vine desiccation (14 days after treatment), skin set, and yield were noted amongst treatments. Residual herbicides are routinely used for weed control in pumpkin. Fluridone and acetochlor formulations applied preemergence were evaluated in direct-seeded pumpkin compared to other labeled herbicides. Fluridone resulted in total crop loss following heavy rainfall immediately after planting; less rainfall resulted in transient injury. Acetochlor formulations resulted in significant pumpkin injury (34 to 39%) 14 days after planting. S-metolachlor controlled weeds similar to acetochlor without significant injury. Palmer amaranth has developed resistance to six different herbicide modes of action. The weed grows rapidly and is best controlled <10 cm in height. To control glyphosate and ALS- resistant biotypes, fomesafen plus dicamba were applied at first postemergence (POST) to small Palmer amaranth (<5 cm, 0 d) and at simulated delays of 7, 14, 21, and 28 d. All plots received lactofen plus dicamba 14 days after first POST. Palmer amaranth control 14 days after first POST was 100% when delayed 0 or 7 d and 62% at the 28 day delay; control increased to 88% following lactofen plus dicamba applied second POST. Yield was significantly reduced when first POST was delayed 28 days at one location. / Master of Science in Life Sciences / Herbicides effectively control weeds by either applying them to the soil prior to emergence or applying them to foliage. Herbicides are used for desiccation of potato vines to facilitate harvest, improve skin set, and regulate tuber size. Potatoes with tougher skin have a longer shelf life and are more resistant to disease. Potato grade classifications include size chef, A, and B potatoes. Size B potatoes hold the greatest value for redskinned potatoes. Experiments were conducted in Virginia to evaluate saflufenacil, glufosinate, saflufenacil plus glufosinate, and carfentrazone plus glufosinate as desiccants compared to diquat applied at 43, 31, and 17% B potatoes. All desiccants resulted in similar vine desiccation 14 days after treatment, skin set, and yield. This research demonstrates that glufosinate and saflufenacil are effective alternatives to diquat for potato vine desiccation; however, further research is needed to evaluate the safety of saflufenacil applied to potatoes prior to harvest. Soil applied herbicides are commonly used in pumpkin production. Fluridone and two acetochlor formulations, herbicides that effectively control troublesome weeds in other crops, were evaluated for pumpkin production in addition to fomesafen, ethalfluralin, clomazone, halosulfuron, and S-metolachlor. Fluridone and acetochlor formulations resulted in significant pumpkin injury early in the growing season and total crop loss was observed by fluridone in 2018. Fomesafen significantly reduced pumpkin iv stand and yield. S-metolachlor, a member of the same chemical family as acetochlor, provided similar weed control without significant pumpkin injury. This research demonstrates that fluridone and acetochlor formulations are poor candidates for pumpkin production. Palmer amaranth is a troublesome weed in soybean that grows rapidly and is resistant to many herbicides. Palmer amaranth is best controlled at a height of 10 cm or less, but timely applications are not always feasible. Fomesafen plus dicamba were applied to small Palmer amaranth (<5 cm, 0 day) and at simulated delays of 7, 14, 21, and 28 days. All treatments received lactofen plus dicamba 14 days after the initial postemergence. Palmer amaranth control 14 days after first postemergence was 100% when application was delayed 0 or 7 day whereas Palmer amaranth control was 62% when first postemergence was delayed 28 days. Lactofen plus dicamba applied second postemergence increased control to 88% when the first postemergence was delayed 28 days. Compared to nontreated plots, Palmer amaranth biomass was reduced 99% by all treatments. This research demonstrates that fomesafen plus dicamba followed by lacofen plus dicamba can be effective for rescue control of Palmer amaranth.

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Estudou-se a interação GE e suas implicações no desempenho agronômico, adaptabilidade e estabilidade de linhagens experimentais de soja transgênicas (tolerantes a herbicidas, RR) e convencionais visando contribuir com a ampliação da base genética da cultura, aumento da produtividade e tolerância/resistência à ferrugem asiática da soja (Phakopsora pachyrhizi). Para isso, 100 linhagens experimentais (50 convencionais e 50 RR) desenvolvidas a partir de dois dialelos parciais 5x2 foram avaliadas. As tecnologias RR e convencional tiveram diferentes manejos com herbicidas. Para cada tecnologia, foram considerados 12 ambientes experimentais formados pela combinação de três anos agrícolas, três localidades e dois manejos com fungicidas (OP = fungicidas para controle de ferrugem, D = fungicida para controle de outras doenças, exceto ferrugem). Os experimentos foram planejados em blocos casualizados com duas repetições e testemunhas em comum. Os dados coletados de produtividade de grãos (PG), peso de cem sementes (PCS), número de dias para a maturidade (NDM) e área abaixo da curva de progresso da ferrugem (AUC) foram analisados com auxílio de modelos mistos, sendo os genótipos considerados como aleatórios. Os componentes da variância foram estimados por REML e os valores genotípicos foram preditos por BLUP. Diversos parâmetros genéticos foram estimados. Um índice ICT (Incremental Crop Tolerance) foi calculado a partir dos efeitos genéticos e foi utilizado para avaliar a tolerância, enquanto que os valores de AUC foram utilizados para verificar a resistência dos genótipos à ferrugem. Também foram realizadas análises de adaptabilidade e estabilidade fenotípica e genotípica com auxílio das metodologias GGE-biplot (Genotype Main Effects and Genotype Environment Interaction) e MHPRVG (Média harmônica da performance relativa dos valores genotípicos). Concluiu-se que: a) Os caracteres PG e PCS foram os mais afetados pela interação GE; b) A existência de interação do tipo complexa reduziu as estimativas de herdabilidade no sentido restrito para PG, PCS, NDM e AUC nas análises conjuntas; c) A seleção de linhagens promissoras para PG, PCS, NDM e AUC utilizando valores genotípicos se assemelhou à seleção utilizando médias ajustadas; d) Os caracteres PG, PCS e NDM foram negativamente afetados pela presença da ferrugem; e) Houve evidências da existência de poligenes agindo no controle da resistência dos genótipos RR e convencionais à ferrugem; f) A tolerância dos genótipos à ferrugem apresentou-se como uma combinação da capacidade intrínseca de suportar certos níveis da doença e também da capacidade de evitar um ataque mais severo da doença apresentada por genótipos de menor ciclo médio; g) A tolerância à ferrugem mostrou-se diretamente relacionada com PG, PCS, adaptabilidade ampla e estabilidade; h) Na metodologia GGE-biplot, utilizar valores genotípicos ao invés de médias fenotípicas ajustadas permitiu explorar melhor a variação disponível para PG, PCS, NDM e AUC; i) O efeito de anos agrícolas agiu fortemente na formação de mega-ambientes para PG e PCS; j) As metodologias GGE-biplot e MHPRVG foram bastante semelhantes na recomendação de genótipos promissores em termos de adaptabilidade ampla, estabilidade e produtividade, mas também foram complementares, ao ponto que GGE-biplot explorou melhor os ambientes experimentais e permitiu indicar genótipos adaptados a ambientes específicos, enquanto que MHPRVG resultou em um ordenamento mais simples e direto, facilitando a seleção de genótipos simultaneamente para adaptabilidade ampla, estabilidade e PG; k) Apesar da tecnologia RR ter tendências de ser mais produtiva, mais resistente à ferrugem e mais tolerante em termos de NDM na média geral, ambas as tecnologias foram consideradas potencialmente análogas para a seleção de genótipos promissores para produtividade, tamanho de sementes, ciclo, estabilidade, adaptabilidade (ampla e específica), tolerância e resistência à ferrugem; l) A linhagem RR 42 (BRS 245 RR x USP 70.007) e as linhagens convencionais 69 (Conquista x USP 70.007) e 76 (BRS 133 x USP 70.108) foram consideradas as melhores linhagens simultaneamente para produtividade, para tolerância e resistência à ferrugem e para estabilidade e ampla adaptação aos ambientes diversos em termos de PG. / This research evaluated the GE interaction and its implications on the agronomic performance, adaptability and stability of transgenic (herbicide tolerant, RR) and conventional soybean experimental lines in order to contribute to increase the soybean genetic base, productivity and tolerance/resistance to rust (Phakopsora pachyrhizi). One hundred experimental lines (50 conventional and 50 RR) developed from two 5x2 partial diallel were evaluated. The conventional and RR technologies had different herbicide managements. For each technology, 12 environments were considered by the combination of three years, three locations and two fungicide managements (O&P = fungicides for rust control, D = fungicide against other diseases, except rust). The experiments were designed in randomized blocks with two replications and two checks. The data of seed yield (PG, kg.ha -1), seed size (PCS, g), number of days to maturity (NDM) and area under the rust progress curve (AUC) were analyzed by mixed models. Genotypes were considered as random effects. The variance components were estimated by REML and the genotypic values were predicted by BLUP. Several genetic parameters were estimated. An Incremental Crop Tolerance index (ICT) was calculated from the genetic effects and was used to assess the genotypes tolerance to rust, while AUC values were used to verify the resistance of genotypes to rust. Phenotypic and genotypic stability and adaptability were performed using the GGE-biplot (Genotype Main Effects and Genotype Environment Interaction) and MHPRVG (Harmonic Mean of Relative Performance of Genotypic Values) methodologies. It was concluded that: a) PG and PCS were the most affected traits by the GE interaction; b) The complex type interaction reduced narrow-sense heritability estimates for PG, PCS, NDM and AUC in the combined analyzes; c) The line selection for PG, PCS, NDM and AUC using genotypic values was the same that using adjusted means; d) PG, PCS and NDM were negatively affected by the presence of rust; e) There was evidence of polygenes acting on the resistance control of rust in the genotypes (RR and conventional); f) The tolerance of genotypes to rust was a combination of the intrinsic capacity of the genotype to support certain levels of the disease and also the ability to avoid a severe attack of the disease presented by early genotypes; g) Rust tolerance was directly related to PG, PCS, wide adaptability and stability; h) Using genotypic values instead of adjusted phenotypic means in GGE-biplot methodology allowed a better exploration of the available variation for PG, PCS, NDM and AUC; i) The year effect was very strong in the formation of mega-environments for PG and PCS; j) The ranking for wide adaptability, stability and productivity by GGE-biplot and MHPRVG methodologies were very similar but the GGE methodology exploited better the environments and indicated genotypes adapted to specific environments while the MHPRVG methodology allowed a simple and direct ordering for broad adaptability, stability and productivity; k) Although RR technology tends in general mean to be more productive, more resistant and more tolerant to rust in terms of NDM, both technologies (RR and conventional) were considered potentially analogous for genotype selection for seed yield, seed size, maturity cycle, stability, adaptability (wide and specific), tolerance and resistance to rust; l) The line 42 RR (BRS 245 RR x USP 70.007) and the conventional lines 69 (Conquista x USP 70.007) and 76 (BRS 133 x USP 70.108) were considered the best genotypes simultaneously for seed yield, tolerance and resistance to rust and for stability and wide adaptation to different environments in terms of PG.