Vigor Reduction Research Articles

Optimized irrigation and fertilization can mitigate negative CO2 impacts on seed yield and vigor of hybrid maize

Seed yield and vigor of hybrid maize determine the planting, yield, and quality of maize, and consequently affect food, nutrition, and livelihood security; however, the response of seed yield and vigor to climate change is still unclear. We established an optimization-simulation framework consisting of a water‑nitrogen crop production function, a seed vigor and a gridded process-based model to optimize irrigation and nitrogen fertilization management, and used it to evaluate seed yield and vigor in major seed production locations of China, the USA, and Mexico. This framework could reflect the influence of water and nitrogen inputs at different stages on seed yield and vigor considering the spatio-temporal variability of climate and soil properties. Projected seed yield and vigor decreased by 5.8–9.0 % without adaptation by the 2050s, due to the 1.3–5.8 % decrease in seed number and seed protein concentration. Seed yield was positively correlated with CO2 and negatively correlated with temperature, while seed vigor depended on the response of components of seed vigor to climatic factors. Under optimized management, the direct positive effects of temperature on seed protein concentration and CO2 on seed number were strengthened, and the direct negative effects of temperature on seed number and CO2 on seed protein concentration were weakened, which mitigated the reductions in both seed yield and vigor. Elevated CO2 was projected to exacerbate the 2.6 % seed vigor reduction and mitigate the 2.9 % seed yield loss without adaptation, while optimized management could increase seed yield by 4.1 % and mitigate the 2.2 % seed vigor reduction in the Hexi Corridor of China, and decrease the seed yield and vigor reduction by 2.4–5.8 % in the USA and Mexico. Optimized management can strengthen the positive and mitigate the negative effects of climate change on irrigated hybrid maize and inform high-yield and high-quality seed production globally.

Ajuste da densidade de semeadura de arroz pelo vigor de sementes

ABSTRACT The use of high-vigor seeds combined with seeding density adjustment at sowing is speculated to ensure high yields. However, certain doubts regarding the effect of this combined approach on rice cultivation remain owing to the tillering capacity. In this context, the present study aimed to determine the effects of seeding density adjustment according to vigor on the initial establishment of seedlings in the field. A physiological characterization was conducted using the germination test, vigor by accelerated aging, electrical conductivity, first count, shoot length, root length, total seedling length, and dry mass in the 2019/2020 and 2020/2021 growing seasons. The evaluations were conducted using a completely randomized design with four replications. Subsequently, the seed lots were selected, from which a fraction of seeds were submitted to artificial vigor reduction. Afterward, these seeds were sown in the main producing regions of the state of Santa Catarina, under a randomized block design with four replications. Three treatment groups were formed: one without density adjustment, one with adjustment by germination, and one with adjustment by vigor in accelerated aging. Twenty-one days after sowing, the number of emerged seedlings per unit area was determined. An interaction between the factors of adjustment for density and seed quality was observed. This was evidenced in the fact that even with the adjustment of density by vigor, the seed lot with lower quality presented the emergence of a lower number of seedlings, and the performance of these seeds was not equivalent to that observed in the lot with superior quality. Accordingly, it was concluded that the seeding density adjustment by vigor combined with the use of seeds with high-vigor is a suitable strategy for achieving a significant increase in plant emergence during the initial establishment in the field.

Quantitative proteomic, physiological and biochemical analysis of cotyledon, embryo, leaf and pod reveals the effects of high temperature and humidity stress on seed vigor formation in soybean

BackgroundSoybean developing seed is susceptible to high temperature and humidity (HTH) stress in the field, resulting in vigor reduction. Actually, the HTH in the field during soybean seed growth and development would also stress the whole plant, especially on leaf and pod, which in turn affect seed growth and development as well as vigor formation through nutrient supply and protection.ResultsIn the present study, using a pair of pre-harvest seed deterioration-sensitive and -resistant cultivars Ningzhen No. 1 and Xiangdou No. 3, the comprehensive effects of HTH stress on seed vigor formation during physiological maturity were investigated by analyzing cotyledon, embryo, leaf, and pod at the levels of protein, ultrastructure, and physiology and biochemistry. There were 247, 179, and 517 differentially abundant proteins (DAPs) identified in cotyledon, embryo, and leaf of cv. Xiangdou No. 3 under HTH stress, while 235, 366, and 479 DAPs were identified in cotyledon, embryo, and leaf of cv. Ningzhen No. 1. Moreover, 120, 144, and 438 DAPs between the two cultivars were identified in cotyledon, embryo, and leaf under HTH stress, respectively. Moreover, 120, 144, and 438 DAPs between the two cultivars were identified in cotyledon, embryo, and leaf under HTH stress, respectively. Most of the DAPs identified were found to be involved in major metabolic pathways and cellular processes, including signal transduction, tricarboxylic acid cycle, fatty acid metabolism, photosynthesis, protein processing, folding and assembly, protein biosynthesis or degradation, plant-pathogen interaction, starch and sucrose metabolism, and oxidative stress response. The HTH stress had less negative effects on metabolic pathways, cell ultrastructure, and physiology and biochemistry in the four organs of Xiangdou No. 3 than in those of Ningzhen No. 1, leading to produce higher vigor seeds in the former.ConclusionHigh seed vigor formation is enhanced by increasing protein biosynthesis and nutrient storage in cotyledon, stronger stability and viability in embryo, more powerful photosynthetic capacity and nutrient supply in leaf, and stronger protection in pod under HTH stress. These results provide comprehensive characteristics of leaf, pod and seed (cotyledon and embryo) under HTH stress, and some of them can be used as selection index in high seed vigor breeding program in soybean.

PATHOGENICITY OF Fusarium graminearum ON CREOLE BEANS: GERMINATION, VIGOR AND SEEDLING DAMAGE

The objective of this study was to evaluate the pathogenicity of Fusarium graminearum by creole bean seeds, quantify the incidence of root lesions and damping off in seedlings, and, evaluate the reduction of germination and seed vigor. Two varieties of creole beans, ‘Cavalo’ and ‘Chumbinho’, were collected from a family property located in the municipality of Severiano de Almeida, RS. The treatments evaluated were: seeds not inoculated (T1) and inoculated (T2) with F. graminearum macroconidia suspension at a concentration of 8.0 x 10 5 macroconidia mL -1 , and was observed the appearance of lesions and the influence on vigor and germination. The variety ‘Cavalo’ proved to be more susceptible to F. graminearum , expressing vigor reduction, incidence of root lesions and damping off . The variety ‘Chumbinho’ expressed no vigor reduction, although it has occurred reduced incidence of damping off . With respect to root lesions, the 'Chumbinho' variety compares to the variety ‘Cavalo’.

Neural response to catecholamine depletion in remitted bulimia nervosa: Relation to depression and relapse

Bulimia nervosa has been associated with a dysregulated catecholamine system. Nevertheless, the influence of this dysregulation on bulimic symptoms, on neural activity, and on the course of the illness is not clear yet. An instructive paradigm for directly investigating the relationship between catecholaminergic functioning and bulimia nervosa has involved the behavioral and neural responses to experimental catecholamine depletion. The purpose of this study was to examine the neural substrate of catecholaminergic dysfunction in bulimia nervosa and its relationship to relapse. In a randomized, double-blind and crossover study design, catecholamine depletion was achieved by using the oral administration of alpha-methyl-paratyrosine (AMPT) over 24 h in 18 remitted bulimic (rBN) and 22 healthy (HC) female participants. Cerebral blood flow (CBF) was measured using a pseudo continuous arterial spin labeling (pCASL) sequence. In a follow-up telephone interview, bulimic relapse was assessed. Following AMPT, rBN participants revealed an increased vigor reduction and CBF decreases in the pallidum and posterior midcingulate cortex (pMCC) relative to HC participants showing no CBF changes in these regions. These results indicated that the pallidum and the pMCC are the functional neural correlates of the dysregulated catecholamine system in bulimia nervosa. Bulimic relapse was associated with increased depressive symptoms and CBF reduction in the hippocampus/parahippocampal gyrus following catecholamine depletion. AMPT-induced increased CBF in this region predicted staying in remission. These findings demonstrated the importance of depressive symptoms and the stress system in the course of bulimia nervosa.

Yield efficiency for nine apple cultivars grafted on two rootstocks

ABSTRACT: Currently, using smaller trees is one of the most important trends in apple cultivation. It is expected that reduced size plants produce lower amount of fruit, but with high yield and yield efficiency. The aim of this study was to evaluate the yield efficiency (YE) of nine apple tree cultivars, grafted on two rootstocks, from the second to the seventh year after planting. The YE indexes oscillated from one to the other year, regardless of rootstock. Correlations between YE and yield per tree and between YE and trunk cross sectional area (TCSA) confirmed that efficiency can be increased by the production increment or by the plant's vigor reduction. The usefulness of cumulative YE (ƩYE) is highlighted to compare apple tree cultivars after the third year of production. The highest ƩYE indexes were observed for 'Royal Gala' and 'Baigent', on M-9 rootstock, and for 'Gala Real' and 'Maxi-Gala', on Marubakaido/M-9 rootstock.

Compatibilidade fenotípica entre cultivares de pereiras europeias eporta-enxertos de marmeleiro

<p>A cultura da pereira (<bold>Pyrus communis</bold>L.) possui grande potencial de expansão no sul do Brasil devido às condições climáticas e de solo. A carência de informações a respeito da(s) melhor(es) combinação(ões) de cultivares 'copa de pereiras europeias' e porta-enxertos de marmeleiro em relação à compatibilidade de enxertia é um dos fatores que tem limitado o cultivo de pera no país. A utilização de porta-enxertos de marmeleiros apresentam as vantagens de redução do vigor e rápida entrada em produção, porém, quando enxertados com algumas cultivares de 'pereira europeia', pode acarretar incompatibilidade de enxertia. O trabalho foi realizado com o objetivo de avaliar fenotipicamente a compatibilidade morfológica entre cultivares 'copa de pereiras europeias' e porta-enxertos de marmeleiro através das variáveis de crescimento das plantas, como o incremento de diâmetro (mm) do tronco da cultivar e do porta-enxerto; diferença de diâmetro entre a cultivar e o porta-enxerto; incompatibilidade 'translocada'; incompatibilidade 'localizada'; e análise da conexão vascular no ponto de enxertia pela imersão em solução corante de Ácido Fuccínico 0,08%. Os experimentos foram conduzidos em pomares de pereiras europeias na região de Urupema, estado de Santa Catarina, durante os ciclos de cultivo 2011/12, 2012/13 e 2013/14. As combinações de cultivares de pereiras europeias e porta-enxertos avaliados foram a 'Abbè Fetel'/'Adams', 'Decana du Comice'/'Adams', 'Clapp's Favourite'/'EMA', 'Rocha'/'Adams', 'Packham´s Triumph'/'EMA' e 'Santa Maria'/'Adams'. A combinação 'Clapp´s Favourite'/'EMA' apresentou incompatibilidade do tipo 'localizada' pela descontinuidade vascular na região de união do enxerto, impedindo a passagem do corante. As combinações 'Rocha'/'Adams' e 'Abbè Fetel'/'Adams' não apresentaram incompatibilidade de enxertia. Nessas combinações, foram observadas união vascular contínua entre as cultivares e os porta-enxertos. As combinações 'Santa Maria'/'Adams', 'Decana du Comice'/'Adams' e 'Packham´s Triumph'/'EMA' apresentaram boa união na zona de enxertia pela continuidade da linha de união na casca e no lenho. A combinação 'Clapp´s Favourite'/'EMA', devido às regiões de incompatibilidade encontradas, não é uma combinação recomendada nas condições experimentais avaliadas. As combinações 'Abbè Fetel'/'Adams' e 'Rocha'/'Adams' são as mais indicadas para plantio, devido à total compatibilidade encontrada entre a cultivar e o porta-enxerto. As combinações 'Santa Maria'/'Adams', 'Decana du Comice'/'Adams' e 'Packham´s Triumph'/'EMA' podem ser recomendadas, devido à compatibilidade parcial de enxertia, sendo indicadas para alta e super densidades de plantio.</p>

The relation of endogenous abscisic acid and indole acetic acid on vigor of some selected dwarf mahaleb (Prunus mahaleb L.) genotypes

Vigor reduction of sweet cherry varieties by dwarfing rootstock is well known, but the mechanism by which a rootstock induces dwarfing is not well understood. Plant hormones have been associated with dwarfing mechanism. This study was conducted, with the main purpose of determining the correlation between of endogenous abscisic acid (ABA) and indole acetic acid (IAA) and vigor of 10 selected dwarf mahaleb (Prunus mahaleb L.) genotypes. Endogenous IAA and ABA levels of selected dwarf genotypes were evaluated, which indicated significant differences for most traits. The IAA level in the shoot bark was the highest in H24 and lowest in M96 genotypes, while ABA level in the shoot bark was highest in M96 and lowest in H14. The mean ABA content decreased as the invigoration capacity of the genotype increased. ABA generally is regarded as an inhibitor of elongation. In our experiment, the endogenous ABA content was negatively correlated with shoot growth. ABA: IAA ratio in shoot bark decreased with increasing genotype vigor. ABA: IAA ratio of the dwarfing genotype M96 was about 1.118. Correlation coefficient showed a significant correlation between crown width, trunk diameter, crown volume, total IAA, total ABA, IAA: ABA and tree vigor. The concentration of ABA in shoot bark showed a good relationship with vigor, thus the content of this phytohormone in shoot bark could be a useful marker of dwarfing character in mahaleb genotype selections. Key words: Mahaleb, Dwarf rootstock, indole acetic acid (IAA), abscisic acid (ABA).

Avaliação do vigor de sementes de tomate durante o armazenamento por meio de análise computadorizada de imagens de plântulas

The aim of this study was to determine the sensitivity of the parameters provided by computerized image analysis to detect tomato seed vigor reduction during storage, compared to tests traditionally used for this purpose. Ten lots of tomato seeds, cultivar Mariana, were stored for 12 months in a controlled environment at 20 ± 1 ° C and 45-50% relative humidity. The seed moisture content was monitored and physiological potential assessed at 0, 3, 6 and 12 months after storage, with germination, first count, accelerated aging with saturated salt solution, seedling emergence tests and with computerized image analyzes of seedlings by SVIS® system. A completely random design was used in a 4 x 10 factorial scheme (4 evaluations periods X 10 lots) with 4 replications. Data were subjected to analysis of variance and mean comparison by the Scott Knott test at 5% probability. Computer image analysis of tomato seedlings with five days after sowing is able to detect vigor differences between lots and vigor loss during storage.

Prohexadiona de cálcio e a redução do vigor, produtividade e qualidade da uva grano d'oro

A Prohexadiona de Cálcio é um regulador de crescimento que atua na inibição da biossíntese de giberelinas, reduzindo o crescimento vegetativo. O objetivo deste trabalho foi avaliar seu efeito na videira Grano d'Oro, mutação da variedade Bordô (Vitis labrusca L.), na redução do vigor, produtividade e qualidade dos frutos. Foi utilizado o produto Apogee®, na concentração de 250 mg L-1 de Prohexadiona de cálcio, em diferentes datas de aplicação. Os tratamentos foram uma aplicação na plena florada, uma aplicação 45 dias após a plena florada e testemunha (sem nenhuma aplicação). O delineamento experimental foi em blocos completamente casualizados, com 4 blocos e 20 plantas por parcela. Ramos marcados foram medidos para a determinação do seu crescimento, e na colheita foi determinado o número de cachos por planta, a produtividade (kg planta-1 e T ha-1), o peso de 50 pagas, o número de bagas por cacho, o teor de sólidos solúveis totais (°Brix), a acidez total titulável (meq L-1) e o pH. A aplicação de Prohexadiona de Cálcio na plena florada reduziu o crescimento dos ramos em 33%, aos 15 dias após a plena florada, diminuindo essa redução ao longo do ciclo, sendo que, aos 93 dias após a plena florada, chegou a 8% em relação aos outros dois tratamentos. A aplicação da Prohexadiona de Cálcio na plena florada causou as maiores reduções no vigor e o maior aumento na produtividade das plantas de Grano d'Oro. O aumento da produtividade e a redução do vigor foram acompanhados por uma redução nos teores de sólidos solúveis totais. A redução no vigor não eliminou a necessidade da realização do desponte.

Evaluación de barreras vegetales en el manejo integrado de la mancha anular del papayo (PRSV-P) en Michoacán, México

El efecto de barreras vegetales como componente de un programa de manejo integrado (MI), se validó y adaptó en 1999 en Michoacán, México, para controlar la Mancha Anular del Papayo, enfermedad causada por el Papaya ringspot potyvirus type-P (PRSV-P). Se estableció un experimento en parcelas divididas con dos factores experimentales: barreras vegetales (Hibiscus sabdariffa), y componentes de MI: MI sin aspersión de citrolina (1.5%) (MI-A), MI sin eliminación de plantas con síntomas iniciales de virosis antes de floración (MI-D) y MI. Las barreras vegetales sembradas 20 días antes del trasplante del papayo y el desplante retrasaron en 19 días el inicio del progreso de epidemias en el MI lo que resultó en una mayor producción (14.2%) que el resto de tratamientos, aunque fue superado por MI-A en vigor (4% en diámetro de tallo). La citrolina fue fitotóxica, disminuyó el vigor de plantas (5.3%) y no limitó significativamente el desarrollo de la enfermedad ya que la intensidad de las epidemias (X0 = 47días, Yf = 84% y ABCPE = 3220% días) fue similar al testigo. El uso de barreras vegetales por si sola aparentemente no es suficiente para la reducción de la incidencia y dispersión de la enfermedad. Los áfidos más abundantes, con reconocida capacidad transmisora del PRSV-P, fueron Aphis gossypii, A. nerii, A. spiraecola y Macrosiphum euphorbiae, los cuales representaron aproximadamente el 13% del total de áfidos capturados.

Evaluation and Modeling of Physical and Physiological Damage to Wheat Seeds under Successive Impact Loadings: Mathematical and Neural Networks Modeling

Threshing wheat (Triticum aestivum L.) at high speeds is the main reason behind abnormal seedlings and vigor reduction of the seeds. This problem is expected to be severe in head‐stripper combines with successive impact loadings of stripping and threshing units. The aim of this study was to simulate the effects of impact velocities (IV), number of impact loadings (NL), and seed moisture content (MC) on percentage of physical damage (PPD) and percentage of loss in germination (PLG) to wheat seeds. Modeling the correlation between dependent and independent variables was performed using mathematical and artificial neural networks (ANN). The result showed that all the three independent variables significantly influenced PPD and PLG (P = 0.01). Increasing the IV from 5 to 30 m s−1 caused an increase in PPD and PLG from 0.17 to 35.8% and from 0.37 to 19.9%, respectively. It was found that the seeds with higher MC could better withstand physical and physiological damage than those with lower MC. With an increase in NL from 1 to 3 times, the mean values of PPD and PLG were increased by 2.9 and 2.6 times, respectively. An ANN model with two hidden layers, trained with a back‐propagation algorithm, successfully learned the relationship between the input and output variables. In comparison with regression models, ANN performed better when predicting PPD and PLG to wheat seeds.

Differential Response of a Virginia Common Lambsquarters (Chenopodium Album) Collection to Glyphosate

Control of common lambsquarters with POST applications of glyphosate in glyphosate-resistant crops generally has been effective. In 2002, common lambsquarters plants from Westmoreland County, VA, were identified after not being controlled with a POST glyphosate application in glyphosate-resistant soybean. Plants from this site that survived glyphosate were collected in both 2002 and 2004. The objective of this research was to evaluate the susceptibility of F1 and F2 progeny from these common lambsquarters plants, relative to the susceptibility of common lambsquarters collected in Montgomery County, VA. F1 progeny of the Westmoreland plants from both the 2002 and 2004 collections showed reduced response to glyphosate relative to the Montgomery collection. Vigor reduction of F1 progeny from three 2004 Westmoreland source plants with 0.84 kg ae ha−1 of glyphosate ranged from 66 to 85% at 28 d after treatment (DAT), compared with 89% for the Montgomery collection. Evaluation of four Westmoreland F2 common lambsquarters lines derived from 2002 collections indicated significant differences in glyphosate sensitivity. Fifteen F2 lines were generated from 2004 collections from each of three Westmoreland source plants and from the Montgomery source. For the least sensitive Westmoreland source, vigor reduction ranged from only 24 to 36% across F2 lines in response to 1.68 kg ha−1 of glyphosate at 28 DAT relative to 55 to 100% for the Montgomery source. I50 estimates for fresh weight reduction were 0.91 and 0.32 kg ha−1, for these sources, respectively. Sequential treatments of 0.42, 1.26, and 1.68 kg ha−1 applied at 3-wk intervals to the least susceptible 2004 Westmoreland F2 line resulted in only 37% vigor reduction and no mortality among 360 treated plants.

Quality of Soybean Seeds Undergoing Moving Bed Drying: Countercurrent and Crosscurrent Flows

The present work describes and analyzes Brazilian research related to the quality of soybean seeds dried in moving bed dryers. The main process variables were drying air temperature, relative humidity and velocity, and solid flow rate. The statistical methodology used allowed the achievement of empirical equations for predicting the quality of soybean seeds (germination, vigor, and fissures) in two classical configurations of the moving bed: countercurrent and crosscurrent. The results show that the increase of the seed coat cracking is associated to conditions that lead to a high drying rate. Germination and vigor reduction is also associated to the overdrying conditions.

Enraizamento de estacas herbáceas de quatro clones de umezeiro (Prunus mume Sieb. et Zucc.) durante o inverno ameno, em Jaboticabal-SP

Estudos realizados no Brasil com o umezeiro (Prunus mume Sieb. et Zucc.) relatam promissoras perspectivas de utilização desta espécie como porta-enxerto para pessegueiro e nectarineira, em função de sua rusticidade, adaptação ao inverno brando, compatibilidade com Prunus persica, redução do vigor das plantas e melhoria da qualidade dos frutos. Entretanto, em função da propagação por sementes, tem sido observadas diferenças de vigor entre as plantas, resultando em pomares muito heterogêneos. Assim, o presente estudo teve por objetivo estudar o enraizamento de estacas herbáceas de quatro clones de umezeiro (Clones 02, 05, 10 e 15) durante o inverno ameno, em Jaboticabal-SP. O experimento foi conduzido entre os meses de junho e agosto, sendo avaliado aos 70 dias após a estaquia. Pelos resultados obtidos, foi possível concluir que é viável a propagação dos clones estudados por enraizamento de estacas herbáceas durante o inverno. Foram observadas diferenças entre os clones quanto à porcentagem de enraizamento, porcentagem de estacas com calo, número e comprimento das raízes. No conjunto das variáveis analisadas, os melhores resultados foram obtidos com os Clones 10 e 15.

Weed Management and Economic Returns in No-Tillage Herbicide-Resistant Corn (Zea mays)1

Field studies were conducted to evaluate corn vigor reduction, weed control, corn yield, and economic returns in a no-till system with various herbicide strategies using full and reduced rates of acetochlor and atrazine with glyphosate, glufosinate, or imazethapyr + imazapyr in their respective type of herbicide-resistant, no-tillage corn. Crop vigor reduction due to herbicide injury was 10% or less with all treatments. A burndown plus a full label rate of a residual herbicide applied early preplant (EPP) generally provided less than 80% control of giant foxtail, common waterhemp, and common cocklebur but usually greater than 85% control of common ragweed and common lambsquarters. Two-pass strategies generally provided greater than 85% control of all species evaluated. Early postemergence, mid-postemergence (MPOST), and late postemergence strategies generally provided inconsistent and poor overall weed control. EPP–MPOST strategies generally provided lower weed control than strategies using acetochlor or ...

Aneuploid hybrids from 5x − 4x crosses in potato: Chromosome number, fertility, morphology and yield

The objective of this study was to characterize six S. commersonU - S. tuberosum progenies deriving from 5x - 4x crosses to provide evidence that they can be used in potato breeding. Hybrids analyzed (coded PTH) had a chromosome number between the 4x and the 5x level. In particular, progeny means for chromosome number ranged from 50 to 54 with most (70%) genotypes exhibiting a low aneuploid level of 48 to 53 chromosomes. Despite being aneuploid, the hybrids did not generally show phenotypic aberrations or vigor reduction common to aneuploids of other species. Most genotypes resembled S. tuberosum in growth habit, whereas corolla type, eye depth, and stolon length varied between and within progenies. Aneuploid hybrids produced tubers under long-day conditions. However, tuber yields were not as high as expected, probably due to lack of adaptation of the S. commersonii genome to long-day conditions. Although aneuploidy has often been associated with reduced male and female fertility, many 5x - 4x hybrids were fertile in crosses with S. tuberosum. The average berry set and number of seeds/berry were 33% and 34.7, respectively, following PTH x S. tuberosum crosses, and 40% and 51.7, respectively, for S. tuberosum x PTH crosses. The useful variation for fertility and tuber traits found in this material is being used for further breeding efforts.

Influence of Corn Rootworm Insecticides on the Response of Field Corn (Zea mays) to Nicosulfuron

Field experiments were conducted in Michigan, Minnesota, and Wisconsin to evaluate injurious interactions between nicosulfuron herbicide applied POST and nine insecticides applied at planting on ‘Pioneer 3751’ field corn in 1991. Insecticides were applied in-furrow, T-band, and surface band at planting. Corn injury from nicosulfuron and terbufos applications was more severe in Wisconsin than in Michigan. No corn injury was observed in Minnesota. Terbufos 15% ai granule (15G) or 20% ai controlled release granule (20CR) increased nicosulfuron injury to corn in Wisconsin. Nicosulfuron at 35 g ai/ha caused the greatest vigor reduction following terbufos 15G, intermediate vigor reduction following terbufos 20CR, phorate 20G, or phorate 20CR, and the least vigor reduction following fonofos, chlorpyrifos, chlorethoxyfos, tefluthrin, or carbofuran in Wisconsin.

Sweet Corn (Zea mays) Hybrid Tolerance to Nicosulfuron

Tolerance of eight processing sweet corn hybrids to nicosulfuron was evaluated in field studies conducted at Arlington, Wis. in 1988 and 1989. Magnitude of sweet corn vigor reduction varied between years. Greater vigor reduction occurred to ‘Jubilee’ sweet corn than to the other seven hybrids. Injury to the hybrids increased as nicosulfuron rate increased. In 1988, some of the hybrids were stunted slightly by all of the herbicide rates, but within a hybrid there was no significant difference among herbicide rates. In 1989 none of the hybrids, including Jubilee, was stunted by even 140 g ai ha–1nicosulfuron compared with the corresponding check. Effects of nicosulfuron on yields of the eight hybrids in 1988 and in 1989 are best described by a quadratic regression equation.

Behavior of an extra chromosome carried by alloplasmic common wheat lines having Agropyron trichophorum cytoplasm.

All the alloplasmic common wheat lines having Agropyron trichophorum cytoplasm were found to carry one extra submetacentric or telocentric chromosome although they had been backcrossed seven times with common wheat as the pollen parent. Behavior of the extra chromosome and its interaction with the A, trichophorum cytoplasm were studied. A, trichophorum cytoplasm was found to induce seed shriveling and severe vigor reduction in common wheat. The extra chromosome originating from A, trichophorum carries a gene(s) for complete restoration of seed plumpness and normal plant vigor. Conscious selection of plump seeds and vigorous plants for backcrossing has resulted in the preferential transmission of the A. trichophorum chromosome in the present alloplasmic lines.