CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
Not a member yet
791 research outputs found
Sort by
A simple, fast and accurate screening method to estimate maize (Zea mays L) tolerance to drought at early stages
Get PDFThere is a great need for the selection of plants with higher drought tolerance, so that fast and effective techniques to identify variations in drought tolerance are mandatory for screening large numbers of genotypes. This work presents a protocol for easy and reliable assessment of responses of maize genotypes to water stress conditions imposed during early stages of development. Three experiments using 11 commercial maize hybrids under four levels of water stress were carried out: i) germination, ii) seedling growth, and iii) early growth bioas- says. Constant and uniform water stress was imposed using solutions of polyethylene glycol 6000 (PEG 6000). Plant material was evaluated for several morphological, physiological and biochemical traits and monitored for photosynthetic efficiency. Principal component analysis (PCA) of these joint experiments revealed that germination percentage, early root development and stomatal conductance were the most useful traits for discriminating maize hybrids according to their tolerance to water stress. A subsequent greenhouse assay performed with two hybrids with contrasting responses under soil drying conditions validated the previous results. According to our results, the key of drought tolerance was a rapid response of stomatal conductance, which allowed a longer survival to stress even under severe desiccation. This work provides the researcher with a simple and reliable screening method that could be implemented as a decision support tool in the selection of the most suitable genotypes for cultivation in areas where water availability is a problem, as well as for the selection of tolerant genotypes to early drought in breeding programs
Brown-midrib genes in maize and their efficiency in dairy cow feeding. Perspectives for breeding improved silage maize targeting gene modifications in the monolignol and p-hydroxycinnamate pathways
Get PDFMaize silage is widely used and comprises the largest part of roughage in dairy cows diets. However, the biological conversion of cell wall carbohydrates into fermentable sugars by rumen microorganisms is hindered by their embedding with lignins, as well as by p-ydroxycinnamic acid cross-linkages between wall components. The use of mutants inducing high cell wall digestibility, such as brown-midrib mutants and especially bm3, is a relevant alternative strategy in breeding silage maize for feeding value, somehow easier than stacking numerous favorable genomic locations with weaker effects. To date, six brown-midrib mutations have been described, but feeding value experiments with dairy cattle have mostly involved the bm3 mutation, which had appeared until now the most promising. A synthesis of 36 published articles on dairy cow feeding with regular and bm3 maize silages, allowing 43 and 42 comparisons for intake and milk production, respectively, highlighted an average extra intake by 1.16 kg per cow per day and an average extra milk production by 1.26 kg per cow per day for cows fed diets based on bm3 silages. The primary benefit of the bm3 mutation in dairy cattle feeding is thus an increased silage intake, allowing lower giving of costly concentrates in animal diets. In addition to genes inducing the brown-midrib phenotype, including the recently identified bm5 and bm6 mutations, a survey of genes involved in secondary wall assembly pointed out several putative targets to be considered in the monolignol and ferulate pathways, as well as several of their upstream regulators. Searches for mutants can be based on the transposon-tagging strategy, but also through gene deregulation, and especially gene editing with the development of the CRISPR/Cas9 technologies. The greater understanding of cell assembly and secondary wall lignification in maize together with the identification of a set of key-genes and their spatio-temporal regulations will allow moving from a limited number of brown-midrib mutants to a larger panel of genetic resources for silage maize improvement, with reduced negative side-effects
Maize Nitrogen Use Efficiency: QTL Mapping in a U.S. Dent x Argentine-Caribbean Flint RILs population
Get PDFThis study was aimed to identify quantitative trait loci (QTL) for nitrogen use efficiency(NUE) and related traits in a maize population derived from a cross between two lines with different genetic background (B100 and LP2). Recombinant inbred lines (181) from this population were evaluated under fieldconditions during two growing seasons, and significant(P < 0.01) phenotypic and genotypic variability was detected for most evaluated traits. Two different mapping methods were applied for detecting QTLs. Firstly, a trait by trait approach was performed on across environments, and 19 QTLs were identified.Secondly, a multi-trait multi-environment analysis detected seven joint QTLs. Almost all joint QTLs had inconsistent additive effects from one environment to another, which would reflectpresence of QTL × Environment interaction. Most joint QTLs co-localized with QTLs detected by indi-vidual mapping. We detected consistent additive effects for grain yield per plant and NUE, as well as for biomass and nitrogen harvest index in some joint QTLs, especially QTL-1 and QTL-6. These QTLs had positive and stable effects across environments, and presence of some genes within these QTL intervals could be relevant for selecting for both NUE and grain yield simultaneously. Up today, this is a firstreport on the co-localization of QTLs for enhan-ced allocation of biomass allocation to grains with NUE, and NUE candidate gene identificaion. Fine mapping of these regions could allow to detect additional markers more closely linked to these QTLs that could be used for marker assisted selection for NUE
Combining abilities in green corn genotypes for yield and industrial quality traits
Get PDFThe general and specificcombining abilities and the reciprocal effects of seven hybrids and two open pollination varieties of green corn were evaluated, aiming the formation of base populations to be used as a source of superior inbred lines. For the purpose of this study, two experiments were carried out in Maringá/PR and Sabáudia/PR, during the crop season of 2014/15. The experiments were evaluated in incomplete block design alpha lattice, with three replications. The parents AM811, HTMV1, Cativerde 02 and AL Piratininga were selected based on their ĝi and the following hybrid combinations AM811 x CD316, AM811 x AG1051, AM811 x HTMV1, AM606 x Cativerde 02 and Al Piratininga x AG4051 presented the most desirable ŝij effects. Regarding the reciprocal effects, the genotype AM811 is recommended to be used as male parent in further hybrid combination
Materiale eterogeneo per agricoltura biologica
Get PDFIl miglioramento genetico dei cereali per l'agricoltura biologica: materiale eterogeneoFrumenti del patrimonioLa registrazione di nuove varietà di girasole Helianthus annuusLa riproduzione dei semi di soia in Italia (2010-2016)Nuove varietà di semi di colza registrati nel catalogo italiano delle varietàElaborabio: analisi delle tendenze del database di semi biologiciIl miglioramento genetico dei cereali per l'agricoltura biologica: materiale eterogeneo, Frumenti del patrimonio, La registrazione di nuove varietà di girasole Helianthus annuus, La riproduzione dei semi di soia in Italia (2010-2016), Nuove varietà di semi di colza registrati nel catalogo italiano delle varietà,Elaborabio: analisi delle tendenze del database di semi biologici.
Brazilian maize landraces variability under high and low phosphorus inputs
Get PDFLandraces are considered important sources of abiotic stress tolerance. Among the different abiotic stresses, phosphorous (P) deficiency is considered one of the limiting factors in tropical and subtropical soils. Thus, the aim of the present work is to evaluate and compare P acquisition and use efficiency in landraces and improved varieties of maize in Brazil and classify varieties based on their performance (yield) under low (efficient versus inefficient)and high (responsive versus non-responsive) P supplementation. It also investigates the relationship among variables in regards to P use efficiency(PUE) and agronomic traits and evaluates genetic diversity among varieties. Thirteen landraces varieties and five improved varieties were evaluated in two P-contrasting experiments (with and without P application during sowing) in two counties (Londrina and Maringá), Paraná, Brazil. There was a wide genetic variability among the varieties for the agronomic and P efficiency traits. P acquisition efficiency(PAE) showed high correlation with PUE and grain yield (GY). On the other hand, no correlation was detected between PUE and GY for P use internal efficiency(PUTE). In the experiment without P at sowing, the improved variety ST0509 showed high values for PUE and GY, whereas, among the landraces, the varieties Amarelão, Caiano and Caiano 2 stood out, being considered promising varieties for future PUE breeding programs
Provitamin A Maize Biofortification in Sub-Saharan Africa
Get PDFMaize (Zea mays L.) has a great potential of combating food insecurity in sub-Saharan Africa because of its wide production and consumption in this region. However, its role in curbing nutrition insecurity is limited due to lack of key micronutrients such as vitamin A. This negates its capacity to be a suitable solution for both food and nutrition insecurities that have plagued many African countries. This has contributed to high prevalence of “hidden hunger” related conditions in the form of vitamin A deficiencytriggered illnesses among others. About fifteenyears ago, HarvestPlus and partners introduced provitamin A maize biofortificaion in Africa to fightVitamin A deficienc. Provitamin A biofortificaion is a technology of increasing the provitamin A density in maize kernels through conventional breeding and/or biotechnology. The suitability of any given breeding strategy depends on the genetics and heritability of the provitamin A accumulation as a trait. This review (1) summarises the impacts of vitamin A deficiencyin sub-Saharan Africa, pointing out the disparities that exist between rural and urban vitamin A deficiencyprevalence in some of the African countries, (2) describes the genetics and molecular science behind maize provitamin A biofortificaion, (3) narrates the progress made so far in terms of maize cultivars development since the inception of maize biofortificaion in sub-Saharan Africa and (4) lastly, challenges of maize biofortificaion and possible solutions are highlighte
Site quality assessment for Pinus sylvestris L. in mixed forests of the central part of "Rhodope Mountains" in northeastern Greece
Get PDFIn this work, site index curves are developed for Pinus sylvestris in Greece, because of the ecological, social and economic importance of the species. Data from the forest of the Central Rhodope Mountains of north-eastern Greece are used. Thirty one dominant trees, which had the mean height of the 100 tallest trees per hectare were randomly selected and cut, in the 1990s. For each sampled tree a stem analysis was conducted. The selected height-age model for Pinus sylvestris was . The mean annual increment from stem analyses was equal to 0.212 m, corresponding to a base age of 68 years. The height estimation, calculated by the selected model, for a 68 year-old tree, is 23 m (SI23). Using the quadratic model as the guide curve for the development of anamorphic site index curves, we produced two more curves, SI20 and SI27. The main findings of this research are that Pinus sylvestris seems to grow faster in height in the productive site of the present study compared with that of Sweden, its growth is similar to that of the two most productive sites in forests in northwestern Spain, and it seems comparable to the fairly productive sites of northwestern Turkey
Marginal/peripheral populations of forest tree species and their conservation status: report for Mediterranean region
Get PDFThe Mediterranean region includes 13 countries among Europe, Near Orient, and Africa. This area is a huge “hot spot” of cultures, religions, socio-economical situations, and of habitats and biodiversity. The report illustrates the geographical and ecological features of the region. Forest ecosystems and vegetation traits, with particular focus on forest species growing at the edge of their distribution range, are here compiled. The accuracy of reports, shows the interest and attention that the Mediterranean countries have for the different and complex situations of marginality that characterizes the presence of many forest species in this region. In this area the occurrence of 166 marginal and peripheral (MaP) populations of different species has been detected. Most of populations are characterised by vulnerability and fragility. Many MaP survive in environmental refugia and /or in isolated stands. However, most of the MaP populations identified by FP1202 experts are located in protected areas and also sometimes registered as seed sources, although Mediterranean region appears heterogeneous with respect to protection measures
The influence of low-frequency variability on tree-rings based climate reconstruction: a case study from central Italy (Roman coast)
Get PDFTree rings are among the best sources of proxy data for reconstructing past climatic records. In this study we explore for the first time what type of climatic signals can be reconstructed from stone pine (Pinus pinea L.) based on tree-rings from central Italy (Roman coast). Samples from 112 stone pine trees from stands with different age classes were collected at two locations, Castel Fusano and Castelporziano. In determining the particular target variable for climate reconstruction we explored a wide range of climatic signals (from monthly to multiple year scale) for correlations with tree ring chronologies produced using a variety of detrending methods. We reconstructed short term (autumn-early winter) and long term (3 years precipitation) signals during the 150 years of available data using the “classical” detrending method but also methods preserving their low frequency variability (ABD and RCS) within the chronologies. By setting the best multiple year precipitation drivers at an annual scale and applying a simple percentile threshold approach, we identified the wettest and driest climatic events. The best accuracy in identifying the climatic thresholds was obtained with the ABD method, which also showed the best cross spectral correlation with a long precipitation record. Our reconstruction underpins that since ca. 1850 the Roman coast has experienced its driest conditions in terms of 2-3 year rainfall sums during the last 50 years of the 20th Century. This finding may be used in the context of identifying the long-term natural variability of the region in relation to climate change as it is expected to affect the Mediterranean