Repositorio Nacional

"Competition and facilitation are important factors affecting seedling survival. These factors probably affect plant distribution and abundance. Interactions between species relate to phylogeny, in that closely related species are likely to compete more for resources and facilitation is expected between more distantly related species. We tested for Tamaulipan thornscrub plants, grown with close and distant relatives if they differed in survival, length and weight of shoots and roots, assuming that closely related species would compete more than distant ones. We also explored whether seed mass was associated with plant size from 1-24 months after germination. We grew plants from Tamaulipan thornscrub, with a sibling or with one individual from other species from 1-24 months. Seedling survival was similar for all species when their seedlings grew alone or under competition, at 1, 6 and 12 months. At 24 months seedling survival of Vachellia farnesiana was lower when grown with Havardia pallens. There was no evidence of stronger competition or facilitation for phylogenetically closer species. Seedling size correlated with seed mass one month after germination but not after 6 months. Maximum and mean adult plant height did not correlate with seed mass or with plant height in our trials. We found no evidence of phylogeny explaining nearest neighbors in competition during germination for Tamaulipan thornscrub."

"La competencia y la facilitación son factores importantes que afectan la supervivencia de las plántulas y probablemente afectan la distribución y abundancia de las plantas. Las interacciones entre especies se relacionan con la filogenia, es probable que las especies estrechamente relacionadas compitan más por recursos y que en las menos emparentadas ocurra facilitación. Se investigó si plantas de matorral tamaulipeco creciendo junto a parientes cercanos y lejanos diferían en supervivencia, longitud y peso de tallos y raíces, asumiendo que las especies estrechamente relacionadas competirían más que las lejanas. También se exploró si el peso de semillas se asoció con el tamaño de la planta entre 1 y 24 meses de edad. Se pusieron a crecer plantas de matorral tamaulipeco, con un hermano o con un individuo de otras especies, de 1-24 meses. La supervivencia de plántulas fue similar para todas las especies cuando éstas crecieron solas o en competencia, a los 1, 6 y 12 meses. A los 24 meses, la supervivencia de plántulas de Vachellia farnesiana fue menor cuando creció con Havardia pallens. No hubo evidencia de una competencia o facilitación fuerte para especies filogenéticamente más cercanas. El tamaño de la plántula se correlacionó con el peso de la semilla únicamente al mes de germinadas. La altura máxima y promedio de la planta adulta no se correlacionó con el peso de semillas o con la altura de la planta. La filogenia no explicó la competencia con los vecinos más cercanos durante la germinación de especies del matorral tamaulipeco."

Phylogeny Seed mass Seedling Shoot/root ratio Tamaulipan thornscrub BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) BIOLOGÍA VEGETAL (BOTÁNICA)

Soil moisture content and maize grain yield under conventional and conservation agriculture practices - results of short term field tests in liselo, Namibia

Christian Thierfelder (2023, [Artículo])

This article focuses on the results from trials developed to monitor the short-term effects of conventionally tilled systems versus CA on soil quality and crop productivity under conditions of the major cropping systems in central, north-central and north-eastern regions of Namibia. Conventional tillage (CT), Minimum tillage (MT), Minimum tillage, mulch (MT-M), Minimum tillage, rotation (MT-R) and Minimum tillage, mulch and rotation (MT-MR) were the primary treatments tested. Significant differences (p≤0.000) among the treatments were observed in the 0-60 cm soil profiles where MT-M plots had the highest soil moisture content (39.8 mm, Standard Error of Mean 0.2815) over the study period. A significant difference (p=0.0206) in grain yield was observed in the second season with CT plots yielding the highest grain yield (3852.3 kg ha-1, standard error of mean 240.35). Results suggest that CA has the potential to increase water conservation and contribute to reduction of the risk of crop failure. Climate change driven degradation under conventional tillage necessitate alternative sustainable tillage methods. Conservation tillage methods and conservation agricultural practices that minimize soil disturbance while maintaining soil cover need to be adopted more locally as viable alternatives to conventional tillage.

Grain Yield Soil Moisture Content CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CONSERVATION AGRICULTURE CONVENTIONAL TILLAGE GRAIN YIELDS SOIL WATER CONTENT MAIZE

Implementing the nature's contributions framework: A case study based on farm typologies in small-scale agroecosystems from the Mexico highlands

Laura Alicia Rodríguez-Bustos natalia palacios rojas (2023, [Artículo])

Small-Scale Agriculture MasAgro CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA MAIZE POLICIES AGROECOSYSTEMS SMALL SCALE FARMING

Application of ammonium to a N limited arable soil enriches a succession of bacteria typically found in the rhizosphere

Yendi Navarro-Noya Marco Luna_Guido Nele Verhulst Bram Govaerts Luc Dendooven (2022, [Artículo])

Crop residue management and tillage are known to affect the soil bacterial community, but when and which bacterial groups are enriched by application of ammonium in soil under different agricultural practices from a semi-arid ecosystem is still poorly understood. Soil was sampled from a long-term agronomic experiment with conventional tilled beds and crop residue retention (CT treatment), permanent beds with crop residue burned (PBB treatment) or retained (PBC) left unfertilized or fertilized with 300 kg urea-N ha-1 and cultivated with wheat (Triticum durum L.)/maize (Zea mays L.) rotation. Soil samples, fertilized or unfertilized, were amended or not (control) with a solution of (NH4)2SO4 (300 kg N ha-1) and were incubated aerobically at 25 ± 2 °C for 56 days, while CO2 emission, mineral N and the bacterial community were monitored. Application of NH4+ significantly increased the C mineralization independent of tillage-residue management or N fertilizer. Oxidation of NH4+ and NO2- was faster in the fertilized soil than in the unfertilized soil. The relative abundance of Nitrosovibrio, the sole ammonium oxidizer detected, was higher in the fertilized than in the unfertilized soil; and similarly, that of Nitrospira, the sole nitrite oxidizer. Application of NH4+ enriched Pseudomonas, Flavisolibacter, Enterobacter and Pseudoxanthomonas in the first week and Rheinheimera, Acinetobacter and Achromobacter between day 7 and 28. The application of ammonium to a soil cultivated with wheat and maize enriched a sequence of bacterial genera characterized as rhizospheric and/or endophytic independent of the application of urea, retention or burning of the crop residue, or tillage.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AMMONIUM CROP RESIDUES WHEAT MAIZE TILLAGE SOIL

Breeding for native genetic resistance to FAW in Africa-adapted early- and intermediate-maturing tropical maize germplasm

Yoseph Beyene Anani Bruce Manje Gowda Andrew Chavangi Prasanna Boddupalli (2023, [Objeto de congreso])

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA BREEDING GENETIC RESISTANCE MAIZE GERMPLASM HYBRIDS

Product profile development and prioritization: Important considerations

Yoseph Beyene (2023, [Objeto de congreso])

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA MAIZE PRODUCTS BREEDING PROGRAMMES MARKET SEGMENTATION TECHNOLOGY GERMPLASM

Use of DH lines in maize breeding programs: CIMMYT experience

Yoseph Beyene (2023, [Objeto de congreso])

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA MAIZE BREEDING PROGRAMMES HYBRIDS MARKER-ASSISTED SELECTION GRAIN YIELDS