Allelopathy for weed control in acid solis with high organic matter

6 páginas.- 5 figuras.[EN] Weeds are one of the major limiting factors in agriculture under temperate humid conditions. Weed control faces a challenge nowadays because developed societies reject synthetic herbicides based on risks for health and environmental conservation. Chemical weed control is dangerous for humans and the environment, and mechanical weeding is too expensive and labor consuming. Some of the new alternatives for weed control are based on allelopathy, which meets some of the new requirements in modern societies. Allelopathy opens interesting solutions that can be used for a sustainable agriculture and even for organic agriculture. The allelopathy approach does not intend the elimination of weeds but the reasonable control of weed population at low levels that allow a sustainable agricultural production. Allelopathy can be made with alternative crops or with forest or agricultural residues. Some of the plants with allelopathy potential are leguminous such as faba been, but also forest residues as the green leaf of eucalyptus can be capitalized. These are partial solutions that can help in minimizing herbicide applications but further research is required.[ES] La flora arvense es uno de los factores limitantes de la agricultura en climas templados húmedos. El control de la flora arvense es un reto actualmente porque las sociedades más avanzadas rechazan el uso de herbicidas sintéticos ya que suponen un riesgo para la salud humana y el medio ambiente. El control químico es peligroso para las personas y el mecánico es costoso y laborioso. Algunas de las nuevas alternativas para el control de la flora se basan en la alelopatía, que responde a los requisitos actuales de la sociedad. La alelopatía abre soluciones interesantes que pueden ser usadas en agricultura sostenible y ecológica. La solución alelopática no intenta la eliminación de las hierbas sino un control razonable que permita el cultivo con bajas poblaciones de hierbas para una agricultura sostenible. La alelopatía se puede hacer con cultivos alternativos o con residuos agroforestales. Algunas plantas con valor potencial para la alelopatía son las habas, pero también residuos forestales como las hojas verdes de eucalipto pueden ser aprovechadas. Estas soluciones son parciales y pueden ayudar a minimizar la aplicación de herbicidas, pero se requieren más investigaciones.Peer reviewe

Quantification of critical factors affecting fitness of the sugary1 mutant in maize

Fitness of sugary1 (su1) is affected by some critical traits that depend on the genotypes and environments, while their effects have not been quantified with convincing statistical methods. The objective of this work was to identify and quantify the critical factors of su1 fitness with different genotypes and environments. We used two pairs of field corn inbreds that differentially affected su1 viability to develop F1, F2, BC1 and BC2. After selfing, Su1 and su1 kernels were evaluated under controlled environmental conditions and in field trials. Multiple regressions showed that dry weight of juvenile plant was affected by early vigour (plant size, colour and health) and emergence in cold conditions; ear weight by plant appearance, number of plants and chlorophyll content; number of ears by plant appearance, number of plants, chlorophyll content and female flowering; and kernel weight by ear weight, number of plants, row number and ear length. The main critical factors for su1 fitness were early vigour and emergence under cold conditions at initial stages, while several adult traits were related with final fitness.Research was supported by the Spanish Plan for Research and Development (project code AGL2007-64218/AGR and AGL2010-22254) and the Diputación Provincial de Pontevedra. A Djemel acknowledges his fellowship from the Spanish Council for Scientific Research (CSIC).MICINNDiputación Provincial de PontevedraCSICPeer reviewe

Plant-KBBE: Cornfed: lntegration of advanced mapping and phenotyping methods to identify key alleles for building European maize ideotypes

1 página, 3 figuras.-- Trabajo presentado al "Gabi Status Seminar" celebrado en Paris (Francia) en Marzo de 2010.-- et al.The project is funded in the framework of the Transnational (France, Germany, Spain) Cooperation within the PLANT-KBBE initiative, with funding from the Agence Nationale de la Recherche (ANR), the Federal Ministry of Education and Research (BMBF). and the Ministry os Science and Innovation (MICINN).Peer reviewe

Defense mechanisms of maize against pink stem borer

The pink stem borer (Sesamia nonagrioides Lef.) is the most important pest of maize (Zea mays L.) in northwestern Spain. The objective of this work was to evaluate defense mechanisms against Sesamia in 10 inbred lines and the 10-parent diallel among these inbreds. Hybrids and inbred lines were tested over 2 yr in northwesternSpain under natural and artificial infestations. Yield of infested and non infested plants per plot were computed to calculate yield loss caused by the pink stem borer attack. Principal component analyses for stem damage traits and for ear damage traits were made for each infestation condition. From the principal component analysis, an index was computed to measure stem damage and ear damage. Damage index under artificial infestation was used to evaluate antibiosis while antixenosis was detected when damage index of each genotype was compared under artificial and natural infestation. The regressions of yield loss on the damage index were used to separate the genotypes into four groups according to the possession of antibiosis and/or tolerance mechanisms. A509, A661, EP31, F7, PB60, and Z77016 showed stem antibiosis. A637, A661, EP31, F7, and PB60 exhibited stem tolerance. A509, A661, and EP31 stood out by their ear antibiosis. A637, A661, F7, and PB60 were tolerant to ear damage. We conclude that the three mechanisms of defense to the pink stem borer attack (antixenosis, antibiosis, and tolerance) were found among inbred lines and hybrids. A multitrait selection scheme using damage traits and yield could improve the defense level against pink stem borer.Research supported by Dep. of Education of the Autonomous Government of Galicia (project XUGA40301B95Xunta de GaliciaN

Short-term effects of organic and inorganic fertilizers on soil microbial community structure and function: A field study with sweet corn

A field study was carried out to analyze the short-term impacts of replacing mineral by organic fertilizers on the microbial and biochemical parameters relevant for soil fertility and crop yield. Three types of fertilization regimes were compared: (1) conventional fertilizer regime with inorganic fertilizer, and combined integrated fertilizer regimes in which 25 % of the nutrients were supplied by either (2) rabbit manure or (3) vermicompost. The effects on microbial community structure and function (phospholipid fatty acid [PLFA] profiles, bacterial growth, fungal growth, basal respiration, β-glucosidase, protease and phosphomonoesterase activities), soil biochemical properties (total C, dissolved organic carbon [DOC], N-NH4 +, N-NO3 -, PO4, total K) and crop yield were investigated in the samples collected from the experimental soil at harvest, 3 months after addition of fertilizer. The integrated fertilizer regimes stimulated microbial growth, altered the structure of soil microbial community and increased enzyme activity relative to inorganic fertilization. Bacterial growth was particularly influenced by the type of fertilizer regime supplied, while fungal growth only responded to the amount of fertilizer provided. The use of manure produced a fast increase in the abundance of PLFA biomarkers for Gram-negative bacteria as compared to inorganic fertilizer. Nutrient supply and crop yield with organic fertilizers were maintained at similar levels to those obtained with inorganic fertilizer. The effects of the organic amendments were observed even when they involved a small portion of the total amount of nutrients supplied; thereby confirming that some of the beneficial effects of integrated fertilizer strategies may occur in the short term.Ministerio de Ciencia e Innovación | Ref. CTM2009-08477Xunta de GaliciaFundación Alfonso Martín Escuder

Diversity among maize populations from Spain and the United States for dough rheology and gluten-free breadmaking performance

Maize is used for bakery and for gluten-free food for coeliac patients. Our objective was assessing diversity for dough rheology and breadmaking in maize with different origins, grain types and growth cycles. Endosperm type affected bread crumb colour having dent maize higher L* and a* and instant recovery speed. Population origin affected flotation index, onset pasting temperature, bread crumb colour, hardness and instant recovery speed. Finally, growth cycle affected flotation index, crumb colour L* and a* and cohesiveness. Water-binding capacity, crumb colour and hardness were the most discriminative parameters for maize. The maize population Andaluz/Daxa was the less distant from wheat parameters, and Tremesino was the most different.Research supported by the Spanish Plan for Research and Development (project codes AGL2013-48852-C3-1-R and AGL2014-52928-C2-1-R), Spanish National Research Council (CSIC), and the European Regional Development Fund (FEDER).Peer reviewe

Genetic diversity in Algerian maize (Zea mays L) landraces using SSR markers

In the Sahara, maize (Zea mays L) has been adapted to extreme environmental conditions during the last five centuries; therefore, this germplasm has a potential value as source of tolerance to stress. No previous report of the genetic diversity of Saharan maize has been published so far. The objective of this study was to determine the genetic diversity of a collection of Saharan maize. Fifteen accessions representing the geographic diversity of Algeria were characterized with 18 SSR. Most loci (93%) were polymorphic; the total amount of alleles was 87 and the average of alleles per locus was 5.8. The total genetic diversity (He) was 0.57, being 69% intra-accessions and 31% inter-accession. Eight of the alleles were accession-specific and belonged to six populations. Genetic distance among the 15 accessions resulted in the definition of three main clusters related to the geographic origin. Maize germplasm from the Algerian Sahara can be classified at least in three groups and the most variable accessions are in the southern oasis. Some accessions were highly variable and can be sources of favorable alleles for breeding for tolerance to extreme stress conditions.This research was supported by the Spanish Agency for International Cooperation and Development (AECID project A/023430/09), the École Nationale Supérieure Agronomique (ENSA) Algiers,Algeria,the Spanish Council for Scientific Research (CSIC) and the Algerian Ministry of high Education and scientific research (MESRS).Peer reviewe

Contribution of autochthonous maize populations for adaptation to European conditions

Early vigor, earliness and cold tolerance are the main potential contributions of European maize (Zea mays L.) for breeding programs for adaptation to areas with short growing seasons and cold springs. The objective of this research was to determine the potential contributions of populations from different European regions to breeding for adaptation. Six Spanish and six French maize populations differing on variability for earliness, vigor and cold tolerance were crossed in a complete diallel without reciprocals. The populations and their crosses were evaluated in the field and in a cold chamber. Minimum temperatures were the main environmental trait affecting genotype × environment interaction, probably due to the cold sensitivity of the genotypes with the best performance in the field. The best population cross, based on specific heterosis for adaptation-related traits in the field, was Viana × Rastrojero, but this cross was cold sensitive. Tuy × Lazcano should be the best choice for a breeding program for adaptation, based on performance in the field and cold tolerance. As conclusions, there was variability for earliness, vigor and cold tolerance among the populations and crosses involved in this study, being tolerant to cold conditions the populations with medium growing cycle originated in areas with short growing seasons. The highest yielding crosses were cold sensitive.Research supported by the Ministry of Science and Technology (Ref. HF1999-0138), the Ministère de l’Education Nationale et de la Recherche, the Committee for Science and Technology of Spain (Project AGL2004-06776), the Autonomous government of Galicia (PGIDIT04RAG403006PR), the Excma. Diputación Provincial de Pontevedra, and the European Union (RESGEN 88 CT96).Peer reviewe

Marcadores moleculares, la horticultura del futuro

Peer reviewe

Breeding maize for cold tolerance

Trabajo presentado en el Simposio organizado por el Núcleo de Estudos em Genética e Melhoramento de Plantas de Lavras, Brasil, en agosto de 2012.N