Estimates of genetic and environmental variability in soybeans (Glycine max. L.) [Egypt].

Principles of Plant Breeding

Large-scale bioenergy demand has triggered new approaches to straw management in Brazilian sugarcane fields. With the progressive shift from a burned to a nonburned harvest system, most of the straw presently retained on the soil surface has become economically viable feedstock for bioenergy production. The trade-offs between the need to preserve soil quality and produce more bioenergy have been the subject of intense discussion. This study presents a synthesis of available information on the magnitude of the main impacts of straw removal from sugarcane fields for bioenergy production and therefore represents an easily available resource to guide management decisions on the recommended amount of straw to be maintained on the field to take advantage of the agronomic, environmental, and industrial benefits. Crop residues remaining on sugarcane fields provide numerous ecosystem services including nutrient recycling, soil biodiversity, water storage, carbon accumulation, control of soil erosion, and weed infestation. Furthermore, several studies reported higher sugarcane production under straw retention on the field, while few suggest that straw may jeopardize biomass production in cold regions and under some specific soil conditions. Pest control is among the parameters favored by straw removal, while N2O emissions are increased only if straw is associated with the application of N fertilizer and vinasse. An appropriate recommendation, which is clearly site specific, should be based on a minimum mass of straw on the field to provide those benefits. Overall, this review indicates that most of the agronomic and environmental benefits are achieved when at least 7 Mg ha−1 of dry straw is maintained on the soil surface. However, modeling efforts are of paramount importance to assess the magnitude and rates of straw removal considering the several indicators involved in this complex equation, so that an accurate straw recovery rate could be provided to producers and industry toward greater sustainability.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcbb.12410

Agronomic and environmental implications of sugarcane straw removal: a major review

Tissue culture is the in vitro aseptic culture of cells, tissues, organs or whole plant under controlled nutritional and environmental conditions [1] often to produce the clones of plants. The resultant clones are true-to type of the selected genotype. The controlled conditions provide the culture an environment conducive for their growth and multiplication. These conditions include proper supply of nutrients, pH medium, adequate temperature and proper gaseous and liquid environment.

/pdf/plant-tissue-culture-current-status-and-opportunities-4hxadl6xjq.pdf

Plant Tissue Culture: Current Status and Opportunities

Soil physical quality response to sugarcane expansion in Brazil

This work aimed to verify the influence of the under shading period in the parameters employed to evaluate Trema micrantha (crindiuva) seedling quality pattern. The research was carried out using a randomized design, with four replications per treatment and 88 plants per replication. Three evaluations were performed at 90, 120 and 150 days after emergence. The following treatments were used in the evaluation: Evaluation I, 45, 60, 75 and 90; Evaluation II, 45, 60, 75, 90, 105 and 120 and Evaluation III, 45, 60, 75, 90, 105, 120, 135 and 150 days under shading with 48% of solar radiation retention, respectively. The morphological parameters of the seedlings, their relationships, and the Dickson quality index were evaluated. Seedlings developed under the longer shading periods presented higher shoot heights and leaf area but the lowest values for seedling quality, such as smaller stem diameter, root dry mass and the Dickson quality index. They also presented an increase in shoot height/stem diameter and shoot/root ratios. Period under shading did not affect significantly the parameters for leaf area, leaf dry mass, shoot and total. Seedlings showed better quality patterns at 120 days, when grown under 45 and 60 days under shading. The Dickson's quality index was the best and the most suitable parameter to evaluate the target seedling grown in a suspended nursery.

https://www.scielo.br/pdf/rarv/v26n4/a15v26n4.pdf

Padrão de qualidade de mudas de Trema micrantha (L.) Blume, produzidas sob diferentes períodos de sombreamento

O objetivo deste trabalho foi estudar os efeitos das doses de fertilizante de liberacao lenta e dois substratos sobre o crescimento e a qualidade das mudas de Coffea arabica L., a fim de gerar parâmetros que permitam a padronizacao e a classificacao da qualidade de cada lote de mudas. Foram utilizados dois substratos (substrato comercial Plantmax® e o vermicomposto de esterco de curral com casca de arroz carbonizada na proporcao de 4:1 v/v) e cinco doses de fertilizante de liberacao lenta: 0, 5, 10, 15, 20kg m-3 de substrato em tubetes com plântulas de Catuai Vermelho IAC 99, conduzidas em viveiro coberto por tela de polipropileno com 50% de sombreamento. Cinco meses apos emergencia, foram determinados a materia seca de raiz, caule, folha, a materia seca total, o numero de folhas, a area foliar, o diâmetro de caule, a altura da parte aerea, a relacao parte aerea raiz, a relacao altura da planta e diâmetro do coleto e o indice de qualidade de Dickson. Para cada caracteristica avaliada dentro de cada substrato, foram testados modelos polinomiais para o efeito de doses de adubo de liberacao lenta. Os substratos necessitaram de adubacao para garantir o crescimento e desenvolvimento adequado das mudas. A dose de 10kg de fertilizante de liberacao lenta por m3 de substrato foi a mais adequada, independentemente do substrato utilizado. Nessa dose, o substrato comercial apresentou desempenho superior para todos os parâmetros de crescimento avaliados. As mudas desenvolvidas em substrato comercial adubado com 10kg de fertilizante de liberacao lenta por m-3 apresentaram a relacao altura da planta e o diâmetro do caule de 4,0; o indice de qualidade de Dickson de 0,21 e a relacao de materia seca da parte aerea e da raiz de 4,7.

/pdf/indices-de-qualidade-e-crescimento-de-mudas-de-cafe-2wx52f2wor.pdf

Índices de qualidade e crescimento de mudas de café produzidas em tubetes

An experiment was conducted to establish a mathematical model based on the linear measurement of the maximum width of the central leaflet to estimate the leaf area of determinate type of snap bean. The measurements were made using the non-destructive method in six plants and the destructive method in four plants on the 21, 30, 37, 44 and 51 days after emergence. The area of each leaflet was obtained by using an area meter LICOR LI-3000 model. The models, obtained by regression, were tested in destructive and non-destructive methods comparing the estimated and the measured leaf area. The model AF = 0.1026*L1,6871 (R2=0.98) was effective to estimate the leaf area (AF) of snap bean plants in non-destructive way showing that the maximum width of the central leaflet (L) estimates the real leaf area.

/pdf/model-to-estimate-the-leaf-area-of-snap-bean-4bnhwm6fi5.pdf

Model to estimate the leaf area of snap bean

The present study was carried out to determine the contribution of main stems and tillers to the total yield of two wheat cultivars (Triticum aestivum L.), Cocoraque and BH-1146, under two water treatments: a) normal field conditions, and; b) irrigation, in Londrina, PR, Brazil. The experiment was an eight replication randomized complete block design with treatments arranged in split-plots. Data on total grain yield, main stem grain yield, tillers grain yield, the ratio between tiller and total grain yield, yield components and other 17 traits were collected. The cultivar BH-1146 had a higher total grain yield in relation to Cocoraque under normal field conditions; i, e., under water stress. Main stem grain yield responded positively and significantly to irrigation which was the main cause of increased yield in both cultivars. The tiller grain yield contributed little to the total yield.

/pdf/main-stem-and-tiller-contribution-to-wheat-cultivars-yield-4eszey6jq2.pdf

Main Stem and Tiller Contribution to Wheat Cultivars Yield Under Different Irrigation Regimes

O efeito da embebicao de sementes de algodao cultivar IPR-120 com cloreto de mepiquat no crescimento e desenvolvimento inicial das plantas foi avaliado em casa de vegetacao. Os tratamentos foram arranjados em esquema fatorial 5x3 (cinco concentracoes do produto, tres tempos de embebicao), com cinco repeticoes. Altura e area foliar foram avaliadas, da emergencia ate o inicio do florescimento. Os tratamentos com cloreto de mepiquat reduziram a altura da planta desde a emergencia, com interacoes entre os fatores analisados. O numero de botoes florais e de ramos, a area foliar, a materia seca da parte aerea e a altura da insercao do no cotiledonar tambem foram reduzidos pelos tratamentos.

/pdf/desenvolvimento-de-plantas-de-algodao-provenientes-de-5a7elk0oqb.pdf

Édison Miglioranza

Papers

Padrão de qualidade de mudas de Trema micrantha (L.) Blume, produzidas sob diferentes períodos de sombreamento

Índices de qualidade e crescimento de mudas de café produzidas em tubetes

Model to estimate the leaf area of snap bean

Main Stem and Tiller Contribution to Wheat Cultivars Yield Under Different Irrigation Regimes

Desenvolvimento de plantas de algodão provenientes de sementes embebidas em cloreto de mepiquat