Pre-harvest Desiccation Research Articles

Pre-Harvest Desiccation in Productivity and Physiological Quality of Cowpea Seeds

ABSTRACT: Pre-harvest desiccation is an important strategy to anticipate harvesting, preventing the seed from being left in the field in unfavorable climatic conditions. However, little is known about the use of desiccants and their application times on cowpea (Vigna unguiculata). The objective of this study was to evaluate the effect of desiccant application at different seasons and of desiccant herbicides on productivity and physiological quality of cowpea seeds. Five dessicants were evaluated: paraquat, paraquat sequential application, glufosinate- ammonium, glyphosate with sequential application of paraquat and paraquat + diuron mixture applied in four seasons: 50% of the pods with green coloration and with seeds formed (season I); 70% of the pods in the purple coloration (season II), 90% of the pods in the coloration brown (season III) and 100% of the pods in the coloration brown (season IV), plus a control without the application of desiccants, in which harvesting was performed when 100% of the pods were brown. The number of days of anticipation of harvest, productivity, uniformity test, mass of one hundred seeds, germination and vigor of the seeds were evaluated. None of desiccation strategies affect the physiological seed quality, independent of the application season. The desquaments paraquat, glufosinate-ammonium and the paraquat+diuron mixture, when applied in seasons I and II, provided anticipation of the harvest in up to 13 days and 9 days, respectively, however, the size of the seeds and consequently the productivity were affected.

QUALIDADE FISIOLÓGICA DE SEMENTES DE SOJA SUBMETIDAS À DESSECAÇÃO EM PRÉ-COLHEITA

The use of high quality soybean seeds (Glycine maxL.) is one of the most important aspects to obtain satisfactory productivity indexes. The desiccation practice is an important idea of the producers to anticipate theharvest and to minimize the rapiddeterioration of seed quality in the field. In this context, the objective of this work was to evaluate the effect of the use of desiccants applied in R7stageon the physiological quality of soybean seeds.The experiment was conducted in experimental area, located in the city of Passo Fundo, Rio Grande do Sul. Four soybean cultivars (FPS Jupiter RR, FPS Paranapanema RR, BRS Tordilha RR and FPS Urano RR) were planted under experimental design, managed according to technical recommendations for the crop.Upon reaching the R7 stage, different desiccation treatments (without desiccation, paraquat, diquat and glufosinate ammonium) were applied to the subplot.The seeds were harvested with a plot harvester and the weight of one thousand seeds, germination test and accelerated aging test were evaluated, being the last two evaluated at 30 and 180 days after harvest. The pre-harvest desiccation at the R7 stage of soybean cultivation did not negatively affect the physiological quality of the seeds and, generally way, for the cultivars FPS Jupiter RR and FPS Urano RR, it was possible to obtain more vigorous seeds at 30 DAC. Under the conditions under which the experiment was conducted, the diquat, paraquat and glufosinate ammonium herbicides can be used for pre-harvest desiccation in the seed production fields.

Yield, germination and herbicide residue in seeds of preharvest desiccated wheat

Abstract: The goals of this study were to evaluate herbicide application rates at different timings for preharvest desiccation of wheat (Trial 1), as well as to evaluate the effect of the timing of herbicide desiccation at preharvest and harvest timing (Trial 2) on yield, germination, and herbicide residue in wheat seed. In Trial 1, treatments consisted of two application rates of glufosinate, glyphosate, paraquat, or paraquat+diuron and a control without application; application time periods were in the milk grain to early dough stage, soft dough to hard dough stage, and hard dough stage. In Trial 2, treatments consisted of different application time periods (milk grain to early dough stage, and soft dough to hard dough stage), different herbicides (glufosinate, 2,4-D+glyphosate, and untreated control), and different harvest times (5, 10 and 15 days after herbicide application). One thousand seeds weight, yield, first and final germination count, and herbicide residue on seeds were evaluated. Preharvest desiccation with paraquat, glufosinate, and 2,4-D+glyphosate at the milk grain to early dough stage reduces wheat yield. Regardless of the herbicide and application rate, application in the milk grain to early dough stage and soft dough to hard dough stage provides greater germination of wheat seeds, except at the lower dose of paraquat. Systemic herbicides accumulate more in wheat seeds.

Crop Level and Harvest Date Impact on Four Ontario Wine Grape Cultivars. II. Wine Aroma Compounds and Sensory Analysis

Pinot gris, Riesling, Cabernet franc and Cabernet Sauvignon from a vineyard in Virgil, Ontario, Canada were subjected by cluster thinning to two crop-level treatments (full crop, half crop), combined with threeharvest dates (commercial harvest (T0), three weeks after T0 (T1), six weeks after T0 (T2)) in a randomised experiment in 2011 and 2012, with wines produced from all treatment replicates. We hypothesised that afull crop with substantially delayed harvest date might have a greater impact on wine aroma than reducing crop level. Wine aroma volatile analysis was carried out by GC-MS, with quantification by calibration withanalytical standards prepared in model wine. Delayed harvest overcame the effects of crop reduction for almost all volatiles. Pinot gris and Riesling displayed increases in varietal aromas in the T1 and T2 wines, e.g. monoterpenes and norisoprenoids, and in esters, aldehydes and alcohols. Reduced concentrations of volatile acids and green odour compounds (e.g. 1-hexanol) with delayed harvest were also evident. Increases in ethanol were related to increased berry sugars, but higher alcohols did not necessarily increase with harvest date. Crop level had little impact on the sensory properties of these cultivars in both seasons. However, delayed harvest resulted in substantial sensorial changes. Due to these chemical and sensorial effects, delayed harvest is recommended, rather than crop-level reduction, to enhance wine quality in these cultivars. Extended harvest, e.g. T2 treatments, was associated with the production of benzaldehyde, diethyl acetal, and higher concentrations of higher alcohols, e.g. isoamyl alcohol and nonanol, which could be linked to pre-harvest desiccation.

Pre-harvest desiccation of castor crop using 2,4-D and glyphosate

Castor is an industrial crop that depends on mechanization of harvest for increased production. The presence of green leaves and fresh fruits at harvest time affects the combine operation. Defoliation and desiccation are thus a requirement for efficient mechanized harvest. Desiccation was evaluated in castor crop sprayed with combinations of 2,4-D and glyphosate. The 12 treatments were combinations of two doses of 2,4-D (670 and 1340 g ha−1 of the a.i.) with three doses of glyphosate (1440, 1880, and 2160 g ha−1 of the a.i.), the same doses isolated, and a control treatment. The herbicides were sprayed at 90 days after emergence, and irrigation was continued until the harvest 21 days later. It was found that 2,4-D promoted full desiccation at any dose regardless of association with glyphosate, and the plants were killed one week after spraying. Glyphosate did not promote complete desiccation of castor plants in the doses tested. Seed yield was not affected in any treatment.

Pre-harvest Desiccation: Productivity and Physical and Physiological Inferences on Soybean Seeds During Storage

The objective of this research is to define which soybean phenological stage is adequate to promote pre-harvest desiccation and to measure the effects of this procedure on the physical and physiological attributes of soybean seeds throughout storage. The experiment was carried out at Fazenda Santa Bárbara da Boa Vista located in the municipality of Cabeceiras, Goiás, Brazil. The experimental design was the randomized blocks arranged in a factorial scheme being five phenological stages of soybean development where desiccant was applied (R5.5, R6.0, R7.1, R7.3 and R8.3) × five post-harvest storage times (0, 40, 80, 120, 160 days), arranged in four replicates. The measured characters were: Productivity, Mass of one thousand seeds, Retention of sieves 5.5 mm, 6.0 mm and 6.5 mm, Germination, Accelerated aging and Field emergence. The application of the Paraquat molecule in soybean plants in the phenological stages R5.5 and R6.0 compromises the physical attributes, mass of a thousand seeds and productivity. The germination and vigor of the soybean seeds are adversely affected due to the early desiccation of the plants, and these effects are potentiated throughout the seed storage.

Application of Non-Selective Herbicides in the Pre-Harvest of Wheat Damages Seed Quality

Pre-harvest desiccation in order to minimize the time of exposure to abiotic factors after physiological maturity is a practice used in the production of quality seeds. The aim of this work was to evaluate the physical, physiological and sanitary quality of wheat seeds from plants that received non-selective herbicide application at pre-harvest. For this, the treatments were applied on pre-harvest culture. A completely randomized design was applied. We use the herbicides (glufosinate-ammonium, glyphosate and paraquat), phenological stages of herbicide application (Z-83, Z-85, Z-87, Z-92) and additional treatment (without application). The routine tests that express the physical, physiological and sanitary integrity of seeds were evaluated. For herbicide treatments, there was an 8% and 26% reduction in germination under laboratory conditions for BRS Parrudo and Sinuelo, respectively. Soil emergence was 14% higher for the control treatment, not statistically different for the Z-87 and Z-92 stages and also for the herbicides glufosinate-ammonium and glyphosate for both cultivars. The application of non-selective herbicides on wheat pre-harvest impairs the physical and physiological quality and promotes faster deterioration. Vigor is reduced under stress conditions by cold test and accelerated aging. There is no influence on seed sanity.

Influence of Harvest Aid Herbicides on Seed Germination, Seedling Vigor and Milling Quality Traits of Red Lentil (Lens culinaris L.).

Most red lentil produced worldwide is consumed in dehulled form, and post-harvest milling and splitting qualities are major concerns in the secondary processing industry. Lentil producers in northern temperate regions usually apply pre-harvest desiccants as harvest aids to accelerate the lentil crop drying process and facilitate harvesting operations. This paper reports on field studies conducted at Scott and Saskatoon, Saskatchewan, Canada in the 2012 and 2013 cropping seasons to evaluate whether herbicides applied as harvest aids alone or tank mixed with glyphosate affect seed germination, seedling vigor, milling, and splitting qualities. The site-year by desiccant treatment interaction for seed germination, vigor, and milling recovery yields was significant. Glyphosate applied alone or as tank mix with other herbicides (except diquat) reduced seed germination and seedling vigor at Saskatoon and Scott in 2012 only. Pyraflufen-ethyl (20 g ai ha−1) applied with glyphosate as well as saflufenacil (36 g ai ha−1) decreased dehulling efficiency, while saflufenacil and/or glufosinate with glyphosate reduced milling recovery and football recovery, although these effects were inconsistent. Application of diquat alone or in combination with glyphosate exhibited more consistent dehulling efficiency gains and increases in milling recovery yield. Significant but negative associations were observed between glyphosate residue in seeds and seed germination (r = −0.84, p < 0.001), seed vigor (r = −0.62, p < 0.001), dehulling efficiency (r = −0.55, p < 0.001), and milling recovery (r = −0.62, p < 0.001). These results indicate application of diquat alone or in combination with glyphosate may be a preferred option for lentil growers to improve milling recovery yield.

Productivity and quality of soybean seeds of determinate and indeterminate growth types desiccated in pre-harvest

Desiccation aims to control weeds and cause crop defoliation. The procedure facilitates the work of harvesters, allows earlier harvesting and standardization, and can reduce losses. The objective of this study was to evaluate the effect of pre-harvest desiccation on cycle time, seed yield and seed physiological quality of soybean cultivars of determinate and indeterminate growth types. The determinate and indeterminate cultivars ‘BRS Valiosa’ RR and ‘MSoy 7211’ RR were used for experiment. Three desiccation stages: R5.7, R6.5, R7.3 and a control treatment (R8) were tested in a 2×4 factorial scheme, with four replications. The cycle, seed water content, yield (kg ha -1 ), 100-seed weight, protein content, proportion of seeds per sieve (6.0, 5.5, 5.0 and 4.0mm); greenish, defective and normal seed percentages; and the physiological qualities of the seeds were evaluated. There was interaction between cultivar and desiccation stage for 100-seed weight, seed oil content and germination. In relation to the main factors, cultivars and stage of desiccation, only the 5.5 mm sieve fraction was not significant. Early desiccation at the R5.7 and R6.5 stages reduced yield by up to 27%. It was possible to advance the harvest of ‘MSoy 7211’ by up to 11 days without yield loss. Germination, however, was not affected by stage of desiccation. Desiccation at the R7.3 stage did not reduce the yield, strength or germination in either cultivar.

Effects of pre-harvest chemical application on rice desiccation and seed quality.

Pre-harvest desiccation may increase the efficiency of seed production. Field studies were conducted to determine the effects of diquat, paraquat, and ethephon applications on grain moisture, grain weight, and seed germination of hybrid rice Yanliangyou 88 (Oryza sativa ssp. indica) and conventional rice Wuyunjing 7 (Oryza sativa ssp. japonica). In 2013, we tested 12 treatments applied at four weeks (Yanliangyou 88) and six weeks (Wuyunjing 7) after heading. Results showed that reductions in moisture content were significant two and four days after chemical application. Chemical applications had no adverse effects on 1000-grain weight, germination percentage, or germination index, but there were negative effects on the percentage of normal seedlings. Desiccation effects increased with increase in the period after application, while the effect of ethephon combined with diquat or paraquat on desiccation was limited compared with that of diquat or paraquat alone in a short period after application. In 2013, chemical applications reduced the moisture content by from 0.5% to 6.4%, the germination percentage by from 0% to 3.3%, and the percentage of normal seedlings by from 13.3% to 100.0%. Among the treatments, diquat applied at 120 g/ha resulted in effective desiccation with fewer negative effects on grain weight and seed germination in 2013 and 2014. Therefore, diquat may have potential as a pre-harvest chemical desiccation treatment for rice. These results may provide a basis for developing and implementing protocols for large scale field trials.

Pre-harvest desiccation with glyphosate and quality of stored soybean seeds

Sementes de cultivares convencionais de soja colhidas apos dessecacao quimica das plantas com glifosato podem produzir plântulas anormais, com sintomas de fitotoxicidade que podem persistir mesmo apos o armazenamento devido ao acumulo de residuos toxicos. Este trabalho objetivou avaliar a qualidade de sementes armazenadas de soja colhidas apos dessecacao quimica das plantas com glifosato no estadio R7. Sementes de soja da cultivar Conquista foram produzidas com e sem dessecacao das plantas com glifosato, na dose de 2,0 L ha-1, no estadio de maturidade fisiologica. A qualidade das sementes foi avaliada logo apos a colheita e aos oito meses de armazenamento quanto ao teor de agua, massa, germinacao e vigor. O delineamento experimental foi o inteiramente casualizado, com quatro repeticoes. Os dados foram submetidos a analise de variância e as medias comparadas pelo teste de Tukey (p?0,05), em esquema fatorial 2 x 2. Os resultados mostram efeitos deleterios da aplicacao de glifosato utilizado como dessecante para antecipacao da colheita de sementes de soja de cultivares convencionais. A aceleracao da senescencia das plantas resulta na producao de sementes com menor germinacao e reduzido desenvolvimento de plântulas, apesar de a porcentagem de plântulas anormais ser reduzida apos 8 meses de armazenamento, possivelmente devido a degradacao dos residuos toxicos de glifosate e/ou seus derivados.

Minimized phytotoxic effects of pre-harvest desiccation with glyphosate in soybean seeds

ABSTRACT: Pre-harvest desiccation of soybean plants from non-genetically modified cultivars with glyphosate have shown to be detrimental to seed physiological quality by reducing germination and increasing production of abnormal seedlings. On the other hand, many products have been applied to seeds in order to enhance quality such as growth regulators and micronutrients. This study aimed to verify the phytotoxic effects of pre-harvest desiccation with glyphosate on physiological quality of soybean seeds and if they can be overcome or minimized by the application of micronutrients and biostimulant. Seeds from soybean cultivar Conquista were produced with and without desiccation with glyphosate, at the dose 2.0 L ha?1, applied at physiological maturity stage. Right after harvest, seeds were treated with Co + Mo + B + Zn, Co + Mo and biostimulant; a control, with no treatment, was also evaluated. Physiological quality was assessed by tests of germination and seedling development. Data was submitted to variance analysis. Means were compared by the Tukey test (p ≤ 0.05) and analyzed as a 2 × 3 factorial. Dunnet?s test (p ≤ 0.05) was also applied. Negative effects of pre-harvest desiccation with glyphosate on germination of soybean seeds can be overcome by the application of micronutrients Co+Mo. Applying biostimulant to soybean seeds improves seedling development compared with micronutrient treatments, although it does not minimize detrimental effects of desiccation with glyphosate. RESUMO: A dessecacao em pre-colheita de plantas de soja de cultivares tradicionais com glyphosate tem-se revelado prejudicial a qualidade fisiologica das sementes, em razao da reducao da germinacao e do aumento no numero de plântulas anormais. Por outro lado, muitos produtos, como reguladores vegetais e micronutrientes, tem sido aplicados as sementes com o objetivo de melhorar sua qualidade. Este estudo objetivou verificar se efeitos fitotoxicos da dessecacao em pre-colheita com glyphosate na qualidade fisiologica de sementes de soja podem ser superados ou minimizados pela aplicacao de micronutrientes e biostimulante. Sementes de soja da cultivar Conquista foram produzidas com e sem dessecacao das plantas com glyphosate, na dose de 2,0 L ha, aplicada na maturidade fisiologica. Logo apos a colheita, as sementes foram tratadas com os complexos Co + Mo + B + Zn, Co + Mo e um biostimulante; a testemunha, sem tratamento, tambem foi avaliada. A qualidade fisiologica foi avaliada por testes de germinacao e desenvolvimento de plântulas. Os dados foram submetidos a analise de variância. As medias foram comparadas pelo teste de Tukey (p ≤ 0,05) e analisadas em esquema fatorial 2 × 3. O teste de Dunnet (p ≤ 0,05) tambem foi aplicado. Os efeitos negativos da dessecacao em pre-colheita com glyphosate na germinacao das sementes de soja podem ser minimizados com a aplicacao de Co + Mo. A aplicacao de biostimulante as sementes de soja melhora o desenvolvimento das plântulas, quando comparada com o tratamento com micronutrientes, apesar de nao minimizar os efeitos deleterios da dessecacao com glyphosate.

Qualidade fisiológica de sementes e crescimento de plântulas de feijoeiro, em função de aplicações de paraquat em pré-colheita

A qualidade fisiológica de sementes e o crescimento de plântulas de feijão são influenciados pelo ambiente de produção e por práticas de manejo, como a dessecação química, em pré-colheita. O presente trabalho objetivou avaliar a qualidade fisiológica de sementes e o crescimento de plântulas de feijão, após aplicações de paraquat, em diferentes épocas e doses, em pré-colheita. Utilizou-se delineamento de blocos ao acaso, em esquema fatorial 4x4 (épocas de aplicação x doses do herbicida), com quatro repetições. O paraquat foi aplicado aos 30, 35, 40 e 45 dias após o florescimento da cultura (DAF), nas doses de 0 g ha-1, 200 g ha-1, 400 g ha-1 e 600 g ha-1. Os resultados foram submetidos a análise de variância, sendo as épocas comparadas pelo teste Tukey e as doses por regressão. A germinação, o envelhecimento acelerado de sementes e o comprimento total de plântula não foram prejudicados, após as aplicações de paraquat em pré-colheita. Porém, a germinação, após o teste de frio, e o comprimento da parte aérea de plântula foram afetados pelas épocas de aplicações de paraquat, obtendo-se melhores resultados quando o dessecante foi aplicado aos 30 DAF. A condutividade elétrica de sementes diminuiu linearmente, à medida em que as doses de paraquat aumentaram, e resultado similar foi constatado, também, para o comprimento de raiz primária de plântula, com aplicação aos 30 DAF, e primeira contagem de germinação e índice de velocidade de germinação, com aplicação aos 45 DAF. A qualidade fisiológica de sementes e o crescimento de plântulas foram afetados pela aplicação de paraquat em pré-colheita.

Qualidade fisiológica de sementes de soja colhidas em duas épocas após dessecação com glyphosate

A dessecação de plantas de soja em pré-colheita com glyphosate vem se tornando prática rotineira entre os produtores, apesar de não ser recomendada, pois pode comprometer a qualidade fisiológica das sementes. Objetivou-se avaliar os efeitos da dessecação das plantas em pré-colheita com glyphosate na qualidade fisiológica de sementes de soja colhidas em duas épocas após a aplicação. O delineamento experimental foi em blocos ao acaso, com quatro repetições, em esquema de parcelas subdivididas. As parcelas principais consistiram da dessecação ou não das plantas de soja com glyphosate em pré-colheita, no estádio R7, e as subparcelas da colheita das sementes 7 e 14 dias após a aplicação. As sementes foram avaliadas quanto ao teor de água, dano mecânico, viabilidade, massa de 100 sementes e teor de proteína. A qualidade fisiológica foi avaliada por meio dos testes de germinação, envelhecimento acelerado, condutividade elétrica, comprimento de plântulas e massa da matéria seca das plântulas. A dessecação das plantas de soja em pré-colheita com glyphosate ocasiona redução da germinação das sementes e do desenvolvimento inicial das plântulas. O atraso na colheita reduz a germinação das sementes oriundas de plantas de soja dessecadas com glyphosate em pré-colheita, mas minimiza os efeitos fitotóxicos no desenvolvimento das plântulas.

Dessecação química em pré-colheita da mamona

A mamona (Ricinus communis) tem hábito de crescimento indeterminado, com expressiva desuniformidade de maturação dos grãos, o que dificulta sobremaneira a colheita mecanizada. O objetivo deste trabalho foi avaliar a eficiência do herbicida glifosato, isolado, ou, em mistura com 2,4-D, e também do paraquat, na dessecação em pré-colheita da mamona. Foram realizados dois experimentos de campo, no delineamento em blocos ao acaso, com quatro repetições, em Rancharia-SP, de março a setembro de 2005. No experimento 1, avaliou-se a mistura de doses de 2,4-D e de glifosato, e no experimento 2 a dessecação somente com paraquat. Foi determinado o teor de água da parte aérea de plantas de mamona em diferentes dias após a aplicação (DAA). A dessecação da mamona com a mistura de 2,4-D e glifosato tem efeito somente a partir de 20 DAA. O 2,4-D aplicado isoladamente tem expressiva capacidade de desidratação do dossel vegetal, porém, inferior à da mistura de 2,4-D e glifosato. A melhor dessecação é com 1,34 kg ha-1 de 2,4-D mais 1,42 kg ha-1 de glifosato. A dose de 1,2 kg ha-1 de paraquat reduz expressivamente o teor de água das plantas da mamona, porém, com desempenho inferior ao da mistura de 2,4-D e glifosato.

Aplicação de dessecantes em pré-colheita: efeito na qualidade fisiológica de sementes de soja

Oscilações de temperatura acompanhadas de altos índices pluviais e flutuação de umidade relativa do ar, nas fases de maturação e pré-colheita, podem provocar perdas na qualidade física, fisiológica e na sanidade de sementes. A aplicação de dessecantes em pré-colheita contribui para a redução da exposição das sementes a condições climáticas desfavoráveis e para diminuir a possibilidade de prejuízos à germinação e vigor. Nesta pesquisa o objetivo foi avaliar o efeito da época de aplicação de dessecantes e da antecipação da colheita sobre a qualidade fisiológica de sementes de soja. Os experimentos foram conduzidos com as cultivares MG/BR-46 Conquista e FMT Tucunaré, na safra 2005/2006, e BRS MT Pintado e FMT Tucunaré, na safra 2006/2007, em Alto Garças, MT. Utilizou-se delineamento experimental blocos casualizado, em esquema fatorial 6x2x2x2 (5 tratamentos dessecantes + 1 testemunha, 2 épocas de dessecação, 2 épocas de colheita e 2 períodos de armazenamento). Os tratamentos dessecantes (paraquat, diquat, paraquat+diquat, paraquat+diuron e glifosato) foram aplicados nos estádios reprodutivos R6.5 e R7 e as sementes colhidas quando atingiram grau de umidade entre 17% e 20% (colheita antecipada) e entre 12% e 13% (colheita normal). As sementes obtidas em colheitas antecipadas foram submetidas à secagem em estufa com circulação forçada de ar, a 38 ºC - 40 ºC, até atingirem graus de umidade entre 12% e 12,5%. O desempenho das sementes foi avaliado em testes de germinação, classificação do vigor de plântulas, tetrazólio, emergência de plântulas em campo e comprimento de plântulas. Os dessecantes paraquat, diquat, paraquat+diquat e paraquat+diuron não influenciam a qualidade fisiológica das sementes, enquanto o glifosato provoca danos por fitotoxicidade no sistema radicular de plântulas de soja, afetando negativamente o desempenho da semente. A dessecação realizada nos estádios R6.5 ou R7, com exceção do uso do glifosato, possibilita a produção de sementes com desempenho semelhante. A colheita antecipada proporciona sementes de soja com melhor qualidade fisiológica.

(258) GreenPack-DG, a Pinkeye-type Southernpea with an Enhanced Persistent Green Seed Phenotype

The USDA–ARS has released a new pinkeye-type southernpea cultivar named GreenPack-DG. GreenPack-DG is the first pinkeye-type southernpea to be released that has a persistent green seed phenotype conditioned by both the green cotyledon gene (gc) and the green testa (gt) gene. The new cultivar was developed from a cross between Charleston Greenpack (green cotyledon phenotype) and the breeding line USVL 97-296 (green testa phenotype). Except for longer pods, GreenPack-DG is similar in appearance and maturity to Charleston Greenpack. Dry GreenPack-DG seeds have a richer and more-uniform green seed color than dry seeds of Charleston Greenpack. GreenPack-DG seeds are much less susceptible to color loss due to blanching when harvest is delayed than are seeds of green-cotyledon cultivars such as Charleston Greenpack. Color loss is a critical problem in production systems where preharvest desiccants are used to facilitate mechanical harvesting operations. The 7-day delay between application of the desiccant and initiation of harvesting operations can result in serious color degradation. Results of 3 years of replicated field tests at Charleston, S.C., indicate that GreenPack-DG yields are comparable to Charleston Greenpack yields. The new cultivar has excellent field resistance to blackeye cowpea mosaic virus and does not produce hard seeds. GreenPack-DG is recommended for trial by the frozen food industry as a replacement for Charleston Greenpack. Protection for GreenPack-DG is being sought under the Plant Variety Protection Act.

Effects of pre-harvest desiccants on rice yield and quality

Field studies were conducted from 2000 to 2003 to determine the effect of paraquat and sodium chlorate applied as pre-harvest desiccants on rice yield and quality. In these trials, paraquat and sodium chlorate were applied 7 and 3 d prior to main-crop rice harvest (pre-harvest). In the first study, the rice cultivars Cocodrie, Cypress, and Wells responded differently to desiccants. Paraquat could be an effective desiccant for rice, but dose, application timing, and cultivar must be taken into account prior to its use. In the second study, both doses of sodium chlorate applied 7 d pre-harvest reduced head rice yield, but only the dose of 6.7 kg/ha reduced head rice yield when applied 3 d pre-harvest. Sodium chlorate should be applied to rice as a desiccant at 4.5 kg/ha no earlier than 3 d pre-harvest to avoid losses in grain yield and quality.

Dessecação pré-colheita de soja e Brachiaria brizantha consorciadas com doses reduzidas de graminicida

O objetivo deste trabalho foi avaliar os efeitos da dessecação pré-colheita de soja consorciada com Brachiaria brizantha cv. Marandu, com doses reduzidas de graminicida, na viabilização de colheita mecânica de soja e na capacidade de rebrota e formação de palha de B. brizantha. Foi utilizado esquema fatorial 5x3, com cinco doses do graminicida fluazifop-p-butil - 0, 15, 30, 45 e 60 g ha-1 - e três manejos de dessecação do consórcio - sem dessecação e com dessecação nos estádios R7 ou R8 da soja -, em delineamento de blocos casualizados, com quatro repetições. Foram avaliadas duas testemunhas, soja e B. brizantha em monocultivo, capinadas manualmente. A braquiária foi altamente suscetível à ação do graminicida. O consórcio entre soja e B. brizantha, submetido a 15 g ha-1 de graminicida e dessecado no estádio R7 da soja, permitiu a colheita mecânica da soja e a produção de grãos semelhante à alcançada no monocultivo, proporcionando acúmulo de matéria seca de B. brizantha de 4,6 t ha-1, 60 dias depois da colheita da soja. A B. brizantha consorciada com soja, sem aplicação de graminicida, acumulou 6 t ha-1 de matéria seca na colheita da soja e 9,3 t ha-1 60 dias depois da colheita da soja, e o acúmulo de matéria seca de B. brizantha em monocultivo, nessas duas épocas, foi de 13,3 e 21,6 t ha-1, respectivamente.

Efeito de herbicidas aplicados na pré-colheita na qualidade fisiológica das sementes de feijão

One of the strategies to improve the mechanic harvest performance is using desiccants in pre-harvest application. Thus, an experiment was carried at “Fundacao ABC” experimental area during 2001/2002 season, in Arapoti, Parana State, Brazil. The aim of the study was to evaluate the pre-harvest desiccants effect on common bean seeds quality (germination and vigor) after harvest and after a period of 8 month of storage. The variety Carioca under no tillage system was used. The treatments were applied using a pressured and manual pulverization when the crop shows 55% dry pods. The experimental design was random blocks with 10 treatments and 4 replications (g a.i. ha-1): glufosinate-ammonium + ethephon (120 + 100) + Hoefix (0.2%), glufosinate-ammonium + ethephon (120 + 100) + Agral (0.1%); glufosinate-ammonium + ethephon (240 + 200, and 480 + 400); diquat (300 and 600); glufosinate-ammonium (300); paraquat (240); glyphosate (720), and the control, without application. The averages were compared with the DMS test with 5% of probability. The treatments glufosinate-ammonium + etephon (440 and 880 g a.i. ha-1), diquat (33 and 600 g a.i. ha-1), and glufosinate-ammonium (300 g a.i. ha-1) were adequate desiccants and not affected the germination and vigor of the seeds. Paraquat (240 g a.i. ha-1) and glyphosate (720 g a.i. ha-1) shown less efficiency and affected the germination, since that gliphosate affect the seeds vigor.