Effects of polyacrylamide (PAM) and gypsum on irrigated and dryland potatoes (Solanum tuberosum L.).

An experiment was conducted at Lincoln University to investigate the effects of irrigation, micronised polyacrylamide (PAM) and gypsum on the growth and yield of 'Ilam Hardy' potatoes in 2001-2002. At the final harvest, tuber yields were similar (59 500 kg ha⁻¹). Environmental factors dominated results, particularly January rainfall, which was 150% of the 16-year average. Economic yield (tubers> 113g) was not affected by any treatment and was >80% of total tuber yield. Premium size tubers (> 170g) were 65% of total tuber yields and no treatment affected tuber size distribution. The maximum crop growth rate was higher from irrigated (189 kg DM ha⁻¹ d⁻¹) than dryland plots (174 kg DM ha⁻¹d⁻¹). This reflected differences in leaf area index at two times during the later growth period. Mean crop growth rate, as a result, was also lower (118 kg DM ha⁻¹ d⁻¹) compared to irrigated plots (130 kg DM ha⁻¹ d⁻¹). The duration of growth was similar (125 days) for all treatments. There was no effect of any treatment on soil adherence to tubers. Aggregate stability was increased 24% by gypsum application. However, poor initial soil structure caused by years of intensive cultivation meant this only increased to 2.4% and was unlikely to have had any affect on crop growth and yield

Dryland pasture yields and botanical composition over 5 years under sheep grazing in Canterbury

Annual dry matter (DM) production and botanical composition of six dryland pasture combinations, grown under sheep grazing at Lincoln University for 5 years, are presented. In 4 years, lucerne produced the highest DM yields (13.1-18.5 t/ha/yr) through higher daily growth rates, compared with grass based pastures, particularly during periods of water stress in summer and autumn. Of the grass based pastures, cocksfoot sown with subterranean clover produced yields of 9.9-12.9 t DM/ha/yr which were greater than, or similar to, all other pastures (8.0-12.9 t DM/ha/yr). Cocksfoot established with white clover produced >9.7 t DM/ha/yr in years with wetter than average summers. Over the 5 years the contribution of perennial ryegrass to total DM yield declined by ~0.7 t/ha/yr, from 70% in Year 1, to 44% in Year 5. It was replaced by unsown dicotyledonous weeds and grasses which increased from 4% in Year 1 to 24% by Year 5. Overall results show a dryland pastoral system that includes both lucerne and cocksfoot with subterranean clover pastures is likely to produce more feed in dry years than perennial ryegrass/white clover pastures. The inclusion of white clover with cocksfoot and subterranean clover may allow utilisation of variable and unpredictable rainfall in moist summers.A. Mills acknowledges financial assistance from Meat & Wool NZ through the FoRST Pastoral21 programme, Lincoln University and the Cocksfoot Growers Association

Progênies híbridas de grama forquilha : avaliações agronômicas

Paspalum notatum Flüggeis one native forage grasses of southern Brazil. Through intraspecific hybridization, is possible generating progenies with variability for agronomic traits.The objective of this work was to evaluate 24 hybrids and select them for the superior agronomic traits, as well analyze correlations between forage traits that can assist in the selection of genotypes.The hybrids were obtained from crosses among sexual and apomictic clones, and were vegetative propagated in a greenhouse until the transplant to the field. The agronomic traits evaluated were: total green mass (TGM), leaf dry mass (LDM), stem dry mass (SDM), inflorescence dry mass (IDM), dead mass (DeM), total dry mass (TDM),growth habit (GH). Correlations between plant diameter (PD), number of tillers (NT), total dry matter (TDM), plant height (PH), total green matter (TGM), leaf dry matter (LDM), stem dry mass (SDM), number of inflorescences (NINF) and inflorescence dry matter (IDM) were performed using the Pearson correlation coefficient. The hybrids had great variability in all agronomic characteristics measured. Based on the three years of evaluation, hybrids KD9, KF1, KF4, and KD5 produced higher total dry mass than othergenotypes. The hybrid KF4 too had greater LDM; KF1 and KF4 were the colder tolerant. These genotypes were selected for evaluations, such as seed production, fertilizer use efficiency, animal performance, and for new crosses. The high correlation of the total dry mass with the other forage components will be useful for indirect select criteria in bahiagrass improving strategies.Paspalum notatumFlügge é uma gramínea forrageira nativa do sul do Brasil. Hibridizações intraespecíficas geram progênies com variabilidade para características agronômicas. O objetivo deste trabalho foi avaliar 24 híbridos e selecioná-los pelas características agronômicas superiores, bem como analisar correlações entre características forrageiras que possam auxiliar na seleção de genótipos. Os híbridos foram obtidos através dos cruzamentos entre clones sexuais e apomíticos, e foram propagados vegetativamente em casa de vegetação até o transplante para o campo. As características agronômicas avaliadas foram: massa verde total (MVT), massa seca das folhas (MSF), massa seca do caule (MSC), massa seca da inflorescência (MSI), material morta (MM), massa seca total (MST), hábito de crescimento (HC). As correlações entre diâmetro da planta (DP), número de perfilhos (NP), massa seca total (MST), altura da planta (Alt), massa verde total (MVT), massa seca das folhas (MSF), massa seca do caule (MSC), número de inflorescências (NINFL) e massa seca das inflorescências (MSINFL) foram realizados utilizando o coeficiente de correlação de Pearson. Os híbridos tiveram grande variabilidade em todas as características medidas. Em três anos de avaliações, os híbridos KD9, KF1, KF4 e KD5 produziram maior MST; KF4 apresentou maior MSF; KF1 e KF4 foram os mais tolerantes ao frio. Esses genótipos foram selecionados para avaliações de produção de sementes, eficiência no uso de fertilizantes, desempenho animal e para novos ciclos de cruzamentos. A alta correlação da massa seca total com outros componentes da forragem será útil para critérios de seleção indireta em estratégias de melhoramento da grama forquilha

Hybrid progenies of Bahiagrass: agronomic evaluation

Paspalum notatum Flügge (bahiagrass) is one of the most common native grasses found in southern Brazil and have become one of the most promising forage species considering their value for beef cattle production in the tropics and subtropics. The breeding program has been possible through intraspecific hybridization among sexual and apomictic clones, generating progenies with variability for agronomic traits. Hybrid materials with superior agronomic performance can be selected, registered and protected to be made available as a commercial cultivar. The objective of this work was to evaluate 24 intraspecific hybrids and select them for the superior agronomic traits, as well analyze correlations between forage traits that can assist in the selection of genotypes. Based on the three years of evaluation, hybrids KD9, KF1, KF4, and KD5 produced higher total dry mass than other genotypes. The hybrid KF4 too had greater leaf dry matter; KF1 and KF4 were the more cold tolerant. These genotypes were selected for new cycles of hybridization and field evaluations, such as seed production, fertilizer use efficiency and animal performance. The high correlation of the total dry mass with the other forage components might be useful for indirect select criteria in bahiagrass improving strategies.Paspalum notatum Flügge is one native forage grasses of southern Brazil. Through intraspecific hybridization, is possible generating progenies with variability for agronomic traits. The objective of this work was to evaluate 24 hybrids and select them for the superior agronomic traits, as well analyze correlations between forage traits that can assist in the selection of genotypes.The hybrids were obtained from crosses among sexual and apomictic clones, and were vegetative propagated in a greenhouse until the transplant to the field. The agronomic traits evaluated were: total green mass (TGM), leaf dry mass (LDM), stem dry mass (SDM), inflorescence dry mass (IDM), dead mass (DeM), total dry mass (TDM), growth habit (GH). Correlations between plant diameter (PD), number of tillers (NT), total dry matter (TDM), plant height (PH), total green matter (TGM), leaf dry matter (LDM), stem dry mass (SDM), number of inflorescences (NINF) and inflorescence dry matter (IDM) were performed using the Pearson correlation coefficient. The hybrids had great variability in all agronomic characteristics measured. Based on the three years of evaluation, hybrids KD9, KF1, KF4, and KD5 produced higher total dry mass than other genotypes. The hybrid KF4 too had greater LDM; KF1 and KF4 were the colder tolerant. These genotypes were selected for evaluations, such as seed production, fertilizer use efficiency, animal performance, and for new crosses. The high correlation of the total dry mass with the other forage components will be useful for indirect select criteria in bahiagrass improving strategies

Dissimilaridade entre ecótipos de Andropogon lateralis submetidos a diferentes frequências de desfolha e alturas de corte

Andropogon lateralis Nees is a native grass of southern Brazil and is one of the most frequent specie found in native grasslands. The species is widely distributed and has a high degree of phenotypic plasticity, which makes it highly adaptable to different edaphoclimatic conditions and management. This study aimed to evaluate the behavior of twelve ecotypes of A. lateralis, collected in different regions of the state of Rio Grande do Sul and cut to three different heights and subjected to two different defoliation frequencies. From September to February, the ecotypes were evaluated for total dry matter, leaf and stem yields. In addition, total, vegetative and reproductive tillers and plant height were measured. These characteristics are important for the selection of superior genotypes in terms of genetic variability and forage production. Total dry matter and leaf dry matter are characteristics with agronomic importance and they showed the highest correlation (r = 0.77), enabling an indirect selection for one of these characteristics. The natural selection of plants resulted in distinct structural, morphological and productive characteristics with heterogeneity that allows the selection and grouping according to the characteristics, ecotypes with superior agronomic characteristics can be included in breeding programs.Andropogon lateralis Nees é uma gramínea nativa do sul do Brasil e uma das espécies mais frequentes na flora dos campos nativos da região. Possui ampla distribuição e alto grau de plasticidade fenotípica, tornando-o adaptável as condições edafoclimáticas e a práticas de desfolha. Este estudo teve como objetivo avaliar a dissimilaridade entre doze ecótipos de A. lateralis N., coletados em diferentes regiões do Rio Grande do Sul, submetidos a duas frequências de desfolha e três alturas de corte. No período de setembro a fevereiro, os ecótipos foram avaliados quanto à produção de matéria seca total, de lâminas foliares e de colmo. Além disso, foram medidos o número de perfilhos totais, vegetativos e reprodutivos e a altura das plantas. Essas características são importantes para a seleção de genótipos superiores em termos de variabilidade genética e produção de forragem. A matéria seca total e a matéria seca foliar são características com importância agronômica e apresentaram a maior correlação (r = 0,77), possibilitando uma seleção indireta para uma dessas características. A seleção natural das plantas resultou em características estruturais, morfológicas e produtivas distintas com uma heterogeneidade que permite a seleção e agrupamento de acordo com as características, ecótipos com características agronômicas superiores podem ser incluídos em programas de melhoramento

Annual yield and botanical composition of four dryland grass species with or without nitrogen over six years

Nitrogen (N) and water availability affect pasture production and persistence. Yield and botanical composition of four monocultures of brome (BR), cocksfoot (CF), perennial ryegrass (RG) and tall fescue (TF) were evaluated with (+N) or without (-N) N at Ashley Dene farm, Canterbury, over six growth seasons from establishment in 2014/15 (Year 1) to 2019/20 (Year 6). Total annual yields ranged from 2.04 (RG-N; Year 1) to 12.7 t DM/ha/yr (CF+N; Year 3). Yields differed among species in Years 1, 3, 4 and 6 when TF pastures had the lowest production. There was no difference in DM production from BR, CF and RG pastures. Additionally, +N pastures produced ~55% more yield than –N pastures in Years 3 and 5 when spring/summer rainfall was adequate to maintain growth. Sown grasses accounted for >89% of total DM yield in Years 1 and 2 but the proportion of total annual DM production from sown species declined from Year 3. By Year 6, sown species accounted for 48±3.3 (TF) to 64±3.3% (BR, CF and RG) of total annual DM production. Generally, TF failed to perform in this dryland environment. In contrast, the production and persistence of the other three species were not different when subjected to water deficits alone

Multivariate analysis reveals genetic diversity in Paspalum notatum Flügge

The objective of this study was to evaluate 94 Paspalum notatum genotypes over two growing seasons to estimate genetic dissimilarity through agronomic traits and the distance between genotypes. This information is used to create an ideotype from the best averages obtained for the set of characteristics evaluated. Seven apomitic, three sexual, and 81 hybrid genotypes were compared with native genotypes “André da Rocha”, “Bagual”, and cultivar “Pensacola” as controls. There is genetic variability in P. notatum for the studied characteristics, and distinct genotypes with superior characteristics can be used in new combinations between apomictic and sexual plants to obtain hybrids. The characters with the greatest relative contribution to the dissimilarity between the genotypes were tiller density, stem dry mass, and leaf dry mass yield. Thus, these characteristics are suitable criteria to infer genetic distance studies in P. notatum. The selection index based on the ideotype is an auxiliary tool in the breeding process. The ideotype must be based on characteristics of interest according to the objective of the breeding program, as well as on the breeder’s prior knowledge in relation to culture

GABA(A) receptor function is enhanced by Interleukin-10 in human epileptogenic gangliogliomas and its effect is counteracted by Interleukin-1 beta

Gangliogliomas (GGs) are low-grade brain tumours that cause intractable focal epilepsy in children and adults. In GG, as in epileptogenic focal malformations (i.e., tuberous sclerosis complex, TSC), there is evidence of sustained neuroinflammation with involvement of the pro-inflammatory cytokine IL-1β. On the other hand, anti-inflammatory mediators are less studied but bear relevance for understanding seizure mechanisms. Therefore, we investigated the effect of the key anti-inflammatory cytokine IL-10 on GABAergic neurotransmission in GG. We assessed the IL-10 dependent signaling by transcriptomic analysis, immunohistochemistry and performed voltage-clamp recordings on Xenopus oocytes microtransplanted with cell membranes from brain specimens, to overcome the limited availability of acute GG slices. We report that IL-10-related mRNAs were up-regulated in GG and slightly in TSC. Moreover, we found IL-10 receptors are expressed by neurons and astroglia. Furthermore, GABA currents were potentiated significantly by IL-10 in GG. This effect was time and dose-dependent and inhibited by blockade of IL-10 signaling. Notably, in the same tissue, IL-1β reduced GABA current amplitude and prevented the IL-10 effect. These results suggest that in epileptogenic tissue, pro-inflammatory mechanisms of hyperexcitability prevail over key anti-inflammatory pathways enhancing GABAergic inhibition. Hence, boosting the effects of specific anti-inflammatory molecules could resolve inflammation and reduce intractable seizures

Genetic parameters, prediction of gains and intraspecific hybrid selection of Paspalum notatum Flügge for forage using REML/BLUP

Genetic improvement of native forage species is a sustainable alternative for maximizing livestock production. Paspalum notatum Flügge is the most important forage grass in the native grasslands of southern Brazil, with substantial potential available for further genetic improvement. The objective of this study was to quantify a range of genetic parameters and predict yield gains in a population of P. notatum intraspecific hybrids. Results indicated intraspecific hybrids of P. notatum had high magnitudes of heritability in the broad and average sense of genotype, plus high selective accuracy and genetic variation for all forage characteristics evaluated. This indicated REML/BLUP can contribute useful information for plant selection in future plant breeding programs. The genetic material studied showed high genetic variability for forage production. Analysis indicated hybrids 336, 332, 437, 132 and male parent ‘30N’ should be included in new crosses to increase the dry matter production of P. notatum. Parents need to be selected from different groups in order to maximize genetic variability and heterosis. In addition, these parents must be included in diallel crosses. The results obtained in this study provide important information for the future breeding of improved P. notatum cultivars for commercialization

Deconstructing agronomic resource use efficiencies to increase food production

Food production per unit land area needs to be increased, thus cropping systems need to use nutrients, water and solar radiation at as close to maximal efficiencies as possible. We deconstruct these efficiencies into their components to define a theoretical crop ideosystem, in which all resource use efficiencies are maximised. This defines an upper biological limit to food production. We then quantify the difference between maximum use efficiencies and those observed in three agronomic systems (maize, cocksfoot, sugarcane) and identify how, in actual farm systems, efficiencies can be raised to raise food production. We find that crop nutrient use efficiency can be limited by low water availability; thus adding nutrients would not raise production but adding water would. The converse situation of water use efficiency being affected by nutrition is not as evident. Ideosystem thinking can be used to define small- and large-scale agronomic systems that optimize water and nutrient use to maximise food production