CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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Mexican Maize Landraces for Corn on the Cob Production at the Central Highlands
Full text linkConsumption of corn on the cob (Zea mays L.) in Mexico is based on commercial hybrids, even though there areseveral native races selected by farmers for this purpose. The aim of this study was to characterize immature earsfrom genetic material derived from three maize landraces adapted to the Mexican central highlands. We evaluated28 accessions belonging to landraces Cacahuacintle, Chalqueño and Elotes Cónicos in Montecillo, Estado deMéxico under a complete randomized blocks design with two replications for two consecutive cycles. Quality wasmeasured through total soluble solid content, protein content and a sensory analysis, along with morphologicaltraits and yield. We found native genotypes with superior quality than that of the commercial control. An analysisof variance and comparison of means by Tukey’s test, as well as a principal component analysis were applied. Nativemaize showed soluble solid contents of 13.6º Brix, protein content of 12.4 % and better tasting of immatureears than that of the commercial control. Also, the landraces produced ear length of up to 18.5 cm, diameter ofup to 5.3 cm, average of 17 grain rows and 90.8 % of grain fill length, which were similar to the control. The yieldof landraces reached up to 12 t ha-1 of fresh unhusked ears and 6.3 t ha-1 of fresh kernels. Ear length and diametercan be used as selection criteria for improvement of yield and morphologic traits, and soluble solid content forimprovement of tender corn quality. Variability in native maize could satisfy the consumption preferences of cornon the cob and fresh kernel consumption of the population centers of the central part of Mexico
Sowing and fertilization strategies to improve maize productivity
Full text linkField experiment was conducted to examine the impacts of two sowing dates (8 April - first date of sowing and 21 April - second date of sowing) and four nitrogen rates (0, 60, 120 and 180 kg ha-1) on the productivity of maize hybrid ‘ZP 434’ in the Pannonian region of Serbia during 2016 and 2017 seasons. The dry period during late vegetative development and grain filling stage in 2017 decreased ear traits, grain yield, starch and oil contents, nitrogen agronomic (NAE) and nitrogen use efficiency (NUE). The highest number of grains per ear, starch and oil contents, starch and oil yields and lower rainfall use efficiency (RUE) and protein content were obtained from the early sowing date. The ear traits, grain yield, RUE, protein content, oil content and yield of starch, protein, and oil significantly increased while NAE, NUE, and starch content significantly decreased with increasing nitrogen rate.The results indicated a significant inverse correlation between starch and protein contents, which prevents the improvement of these two parameters simultaneously. Thus, timely sowing and nitrogen input should be used as long term management strategies for increasing maize yield and grain quality
The effect of gamma radiation and magnetic field on seed germination andseedling growth at low temperature in sorghum x sudangrass hybrids
Full text linkThis study was aimed to provide seed germination and seedling growth of sorghum x sudangrass (Sorghum bicolor (L.) Moench) hybrids at low temperature by using gamma radiation and magnetic field strength. Seeds of two hybrids ("Aneto" and "Sugar Graze") were treated with different gamma doses (0-control, 100 Gy) and magnetic field strengths (0-control and 75 mT) for 72 hours while some were applied with both gamma radiation + magnetic field. Germination trials were carried out for 10 days in an incubator at 15°C temperature. Germinated seeds fromeach treatment were transferred to pots (5 pots with 4 seeds each) and cultured for 28 days in growth chamber at 15°C temperature. In this study, germination percentage, seedling growth percentage, seedling height, root length, seedling fresh and dry weights, and water content of seedling were determined. Lowest results in all parameters in both hybrids were observed in the control treatment without gamma radiation and magnetic field strength application. The highest values in all parameters studied were recorded in seeds treated both by gammaradiation+magnetic field strength applied together in "Aneto", and in seeds treated with magnetic field strength in "Sugar Graze". As a result of the research, gamma radiation and magnetic field strength applied to seed increased seed germination and seedling growth at a low temperature of 15°C
Genotype x environment interaction and stability analysis of grain yield in QPM hybrid varieties
Full text linkMaize (Zea mays L.) is a major staple cereal widely cultivated in different agro-climatic environments of Ethiopia.Maize productivity in the tropical highland region of the country is known by low average yield mainly due to thelack of high yielding and widely adapted improved cultivars. The objectives of this study were to determine G×Einteraction and yield stability of quality protein maize (QPM) experimental hybrids,to identify ideal genotype withhigh average yield depending on the differential genotypic responses to environment, and to form homogeneousgrouping of environments. The study was conducted at seven environments representing the tropical-highlandsub-humid maize growing agro-ecology of Ethiopia in 2015/2016. Thirty-three QPM hybrids and three-commercial hybridchecks were evaluated using a 4 ×9 alpha lattice design. Yield data was analyzed using AMMI and GGEbi-plot methods. Using AMMI analysis, four promising QPM hybrids designated asG31, G7, G19, G29, and G22were identified based on combined stability and average yield.GGEbi-plot displayed that variety Jibatwas closestto the ideal genotype, can be considered as best hybrid whereas G29, G22 were considered as desirably stable genotypes.GGE bi-plot also displayed Holeta as ideal environment and thus considered useful in discriminating thehybrids and representativeness as suitable environment. The GGE analysis delineated the test environments intothree mega-environments useful for targeted evaluation of genotypes. The result of this study indicated specificallyand widely adapted high yielding stable genotypes and also revealed homogeneous test environments
Long-term monitoring and microbiological control programs against lepidopteran defoliators in Sardinian cork oak forests (Italy)
Full text linkThe gypsy moth, Lymantria dispar (L.), and the tent caterpillar, Malacosoma neustrium (L.), are the main cork oak, Quercus suber L., pests in the Mediterranean area and cause complete defoliation in large forest districts. In order to control infestations, large scale aerial applications of insecticides based on Bacillus thuringiensis subsp. kurstaki (Btk) have been carried out in Sardinia (Italy) since 2001. This paper evaluated the frequency of outbreaks in forest districts with varying homogeneity of land use, forest areas annually exposed to defoliation and the effectiveness of control programs based on Btk insecticide applications.The volume of areas annually exposed to defoliation depends on forest homogeneity, as infestations are more frequent in cork oak areas with a lower than 25% canopy cover rate. The microbiological control programme efficiently protected cork oaks from lepidopteran defoliators and caused an overall annual mean mortality of over 60%, with maximum rates of 89.9 and 98.0% for L. dispar and M. neustrium, respectively. To date, approximately 180,000 hectares of cork oak forests have been protected by spraying Btk-based insecticides
Detection And Characterization of Forest Harvesting In Piedmont Through Sentinel-2 Imagery: A Methodological Proposal
Full text linkThis study evaluated the effectiveness of Sentinel-2 (S2) as a tool for early detection and estimation of forest harvesting in the Piemonte Region, which can be used by the regional forest administration. The priority was the detection, at the regional scale, of annual forest cover changes with the following goals: i) mapping of irregular (in respect of the regional Forestry Regulation) forest cuts; ii) quantification of the intensity of the silvicultural interventions. Results are expected to support forest police controls.The proposed procedure is based on a supervised classification approach based on Random Forest algorithm. Accuracy of harvested areas detection proved to be high (overall accuracy 98%). Characterization of the occurred forest cuts was obtained computingthe local coefficient of variationof the normalized difference vegetation index (NDVI) after harvesting, that showed to be a good predictor of forest harvesting intensity
Drought stress response in maize: molecular, morphological and physiological analysis of tolerant and sensitive genotypes
Full text linkThe aim of this work was to develop a physiological method based on transpiration in combination with molecularmethods, i.e., dehydrin gene expression analysis, for identifying the reactions of maize (Zea mays L.) plants thatdisplay different levels of tolerance to drought stress during the generative growth stage. Drought stress wasinduced in two genotypes, 2087 and 2637, by four irrigation treatments. The rate of transpiration and the expressionof the dehydrin genes ZmDHN1 and ZmDHN2 were dependent on genotype and duration and intensityof stress. The yield components were affected by the level of dehydrin gene expression and transpiration rate.Compared with genotype 2637, genotype 2087 a) maintained higher transpiration intensity, even under strongdrought stress conditions, b) exhibited an earlier onset and a higher level of expression both at a lower stressintensity and during the initial phases of the stress reaction, c) showed higher values of yield components, andd) was characterized by a lower water-use efficiency of cob yield. Drought tolerance is of increasing importanceand is one of the breeding targets in maize. However, traditional breeding methods have numerous limitations.The simultaneous use of new molecular genetic techniques and physiological methods could therefore help toelucidate the genetic and physiological basis of plant responses to drought stress and provide more accurateevaluation for screening parental breeding material
Seasonal influence, heat unit accumulation and heat use efficiency in relation to maize grain yield in Pakistan
Full text linkVariations in ambient temperature affect crop yield by modifying the duration of phenological phases and physiologicalprocesses. An experimental study was carried out at the Maize and Millets Research Institute (MMRI),Yusafwala, Sahiwal, Pakistan, to determine the seasonal effects of temperature on indigenous and exotic maize(Zea mays L.) hybrids based on morphological, phenological, physiological and grain quality traits in four differentgrowing seasons: kharif 2016 and 2017, and spring 2017 and 2018. Seven indigenous and three exotic hybridswere sown in a randomized complete block design with a split plot arrangement, in three replications. Significantdifferences between hybrids and growing seasons were found for grain yield, related traits and temperature indices(cumulative heat units, photothermal index and heat use efficiency). Correlation analysis disclosed a significantpositive relationship between grain yield and net photosynthetic rate (0.854, P≤0.01), number of grains per ear(0.624, P≤0.01) and heat use efficiency (0.980, P≤0.01) in spring seasons. During kharif, net photosynthetic rate(0.675, P≤0.01) and heat use efficiency (0.996, P≤0.01) contributed significantly to grain yield, whereas number ofgrains per ear (−0.146, not significant) had no significant impact on grain yield. Cumulative heat units and heat useefficiency resulted the temperature indices with the greatest influence on grain yield, and should be consideredduring the selection of parents to develop high-yielding, climate-smart maize hybrids. Indigenous maize hybridsshowed higher yields and were more heat tolerant than exotic hybrids, and the spring sowing season appearedto be the most suitable for the cultivation of maize crops
Vegetation dynamic post-disturbance in tropical rain forest of Birds's Head Peninsula of West Papua, Indonesia
Full text linkThe tropical rainforest has a high level of biodiversity and plays an important role as a stable ecosystem. However, an anthropogenic disturbance took place in some parts of the tropical rainforest. The recovery of the disturbed forest is less scientifically understood. Therefore, this study aims to examine the recuperation process of vegetation in Fef, Tambrauw Regency, and West Papua, in Indonesia by comparing the composition of primary forest life forms as control of the natural, five-year disturbed, and seven-year disturbed forest. The results showed that the species diversity in the primary forest was not significantly different from the seven-year disturbed forest while the five-year disturbed forest was significantly different from the two types mentioned earlier. Moreover, the similarity index showed that the primary and seven-year disturbed forest were identical and both were different from the five-year disturbed forest. In addition, eight life forms were enumerated, viz. bamboo, climber, fern, herb, rattan, shrub, small tree, and large tree in which they were dynamic during the post-disturbance compared to primary forest. The residual forests should therefore be part of the intention of local people and government, in other not to exploit the forests by allowing the disturbed forests to recuperate naturally.
A century old regeneration problem of Shorea robusta Gaertn. F. in south Asia: SWOT analysis (Review)
Full text linkShorea robusta (Sal) Gaertn. F. a commercially and ecologically important forestry species of south Asia, is facing serious regeneration problem since last century. The continuously diminishing natural regeneration is associated with numerous abiotic and biotic factors, like edaphic, micro-climatic, physiological, genetic, anthropogenic, pathogens, insect-pests, etc. Following a good seed year and timely commencement of monsoon, Sal seeds germinate readily, and thousands of seedlings cover the forest floor. Subsequently, these get afflicted with die-back syndrome impeding shoot growth. Regular fire incidences during hot and dry season further aggravates the problem. Among biotic factors, Hoplocerambyx spinicornis, Cylindrocladium floridanum and Inonotus shoreae causes severe heartwood decay, blight and dieback leading to mortality. Moreover, over-exploitation, illegal felling, grazing, etc., have severely depleted the Sal forest. This review systematically explores the factors contributing to regeneration problem in S. robusta and opines appropriate silvicultural operations and management strategies for the conservation of Sal forests through SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis. We emphasized on the ecological aspects, soil characteristics, micro-climatic factors and importance of associated species to develop sustainable management regimes. Highlighting all facets of Sal regeneration problem and SWOT assessment, we suggest comprehensive weaknesses and threat perceptions to formulate strategies to seal the gaps