CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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Genetic behavior for kernal yield and its physio-agronomic attributes in maize at normal and high temperature regimes
Get PDFCell membrane thermostability and seedling plant biomass were used to select suitable parents for hybridization against high temperature stress from 77 inbred lines. Six diverse parents with respect to high temperature stress tolerance viz; two high temperature tolerant (935006, R2205-5-4), two moderately tolerant (F-165-2-4, F101-7-2-6) and two high temperature susceptible maize inbred lines (F113-1-1-1 and R2304-2) were selected and crossed in a full diallel fashion to evaluate inheritance pattern of physio-agronomic traits. Data regarding physiological traits viz., osmotic potential, transpiration rate, growing degree days (GDDs) to 50% tasseling and agronomic traits viz; number of kernels plant-1 and kernels yield plant-1recorded were at normal and high temperature stress regimes. Analysis of variance revealed highly significant variation (P < 0.01) for all the traits studied except osmotic potential at normal temperature regime which was significant at P < 0.05. Transpiration rate, growing degree days to 50% tasseling, number of kernels plant-1 and kernel yield plant-1 showed partial fitness of the data either at normal or higher temperature regime while osmotic potential showed partial fitness of the data by regression analysis in both temperature regimes. Genetic components of variance and Wr/Vr graph for traits studied depicted preponderance of over dominant gene action except osmotic potential at normal temperature regime which reflected additive gene control at normal temperature regime. High temperature stress modified gene expression in most of polygenic traits
Kernel weight in maize: genetic control of its physiological and compositional determinants in a dent × flint-caribbean RIL population
Get PDFThe genetic control of maize kernel weight (KW) determination could be studied through its physiological and/ or compositional determinants. Our objective was to dissect the genetic control of maize KW by analyzing its physiological (KGR: kernel growth rate; KFD: kernel filling duration) and compositional (protein, oil, starch) determinants in a dent×flint Caribbean RIL population, which combines a broad genetic background with grains of high added value for industry. An additional objective was to determine the stability of the genetic control under contrasting growing conditions, for which soil nitrogen offer was modified across experiments. Heritability (H2) values were high for KW (H2 = 0.74) and intermediate for the other traits (from 0.62 to 0.42). Kernel weight had a strong correlation with KFD (r = 0.69), KGR (r = 0.60) and protein concentration (r = 0.56). Ten joint QTL with inconsistent effects across years and seven epistatic interactions were detected. Despite changes in effect size, most QTL were significant under both environments. Nine QTL were associated with variations in potential KW (KW ), mean KW, KGR and oil concentration, eight with variations in protein and starch concentration and seven with KFD. Epistatic interactions were related to regions with significant main effects. The most important finding was the existence of a common QTL for KW , KGR and KFD on chromosome 5, for which there was no previous report. Results increased our knowledge on the genetic control of KW through its phenotypic and genetic correlation with KFD, confirming the need to explore different physiological strategies in different genetic backgrounds
Marginal/peripheral populations of forest tree species and their conservation status: report for Continental region
Get PDFThe report describes the geographical and ecological characteristics of the European continental region, which is the area that covers most of Central and Eastern Europe. Forest ecosystems and vegetational aspects, with particular emphasis to forest species growing at the edge of their distribution range, are also considered
Evaluation of biophysical, anatomical and biochemical traits of resistance to Sitophilus oryzae L (Coleoptera: Curculionidae) in stored maize
Get PDFSitophilus oryzae L is the most destructive insect pest of stored maize and is widely distributed in tropical regions. In the present study, eighteen maize genotypes were screened for several susceptibility parameters against S. oryzae by using «No Choice method». Biophysical traits (test weight, thousand kernel weight, kernel hardness), anatomical fractions (tip cap, germ, pericarp, endosperm), biochemical variants (starch, protein, oil, sugar) were correlated with insect susceptibility parameters. There is significant relationship among test weight, kernel hard- ness, and insect susceptibility parameters. Pericarp was positively correlated while endosperm, starch content were negatively correlated with median development period but were non-significant. Majority of the maize geno- types containing harder kernels and thick pericarp showed less susceptibility to S. oryzae. The results indicated that the biophysical, anatomical and biochemical traits are responsible for varying levels of resistance to S. oryzae
Estimation of genetic diversity of germplasm used to develop insect-pest resistant maize
Get PDFGenetic diversity is important in ensuring viability of germplasm for a breeding program. The objective of this
study was to determine the genetic diversity of 130 S
families from two populations; stemborers’ resistant and
storage pests’ resistant populations, each with 65 lines; using 30 simple sequence repeats (SNP) molecular markers. The markers were found to be polymorphic with 0.46 - 0.48 polymorphism for both populations, except locus umc1367, which was monomorphic for storage pests’ resistant population. A total of 109 alleles were recorded from stemborers’ resistant population. Allele’s scores ranged from 2 to 6 alleles per locus, with a mean of 3.6, and product length ranging from 47 bp to 362 bp. The storage pests’ resistant population had a total of 103 alleles, with scores of 1 to 6 per locus, and a mean of 3.4 alleles; and product length of 47 - 320 bp. Observed gene diversity was 0.27, with expected gene diversity of 0.45 for stem borers’ resistant population and 0.48 storage pests’ resistant population. Mean polymorphism information content values ranged from 0.46 to 0.48, while unbiased expected heterozygosity ranged from 0.4 to 0.45 for both populations. Cluster analysis revealed three major clusters in each population; with cluster 1 comprising 34 - 40% of the genotypes in both populations. Cluster 2 had
55% for stem borers’ resistant genotypes, and 53% of storage pests’ resistant genotypes. The study indicates that there is ample genetic diversity in both populations which can be exploited in extracting new inbred lines for use in breeding insect resistant maize hybrids
Effect of the few-branched-1 (Fbr1) tassel mutation on performance of maize inbred lines and hybrids evaluated under stress and optimum environments
No full textYield can be increased under stress conditions by manipulating the traits that limit yield under these conditions. Tassel size is one such trait. A few branched-1 mutation (Fbr1) was introduced into the maize breeding programme of CIMMYT as a strategy to improve drought tolerance. The aim of this study was to evaluate yield performance of Fbr1 maize lines and hybrids under optimum and stress environments, and to determine associations between tassel size and grain yield under stress and optimum environments. Genotype effects were highly significant for all traits and genotype by environment (GxE) interaction effects were significant for all traits except for kernel row number and anthesis silking interval. Generally Fbr1 x Fbr1 hybrids had lower grain and pollen yields, and were less adapted to abiotic stress conditions. Positive relationships between grain yield components and pollen yield components were found except for association of prolificacy with tassel branch number and total tassel length under drought stress and optimum conditions. We were expecting that the Fbr1 genotypes could potentially in- crease grain yield under drought stress. It seems that grain yield improvement and stress tolerance is determined by multiple factors, which, when put together can additively contribute to increased yield performance. Although reduction in tassel size could be one of these many factors that contribute to improved grain yield under stress conditions, the factor cannot bring significant improvement on its own. Our results show that the Fbr1 trait reduce pollen production in genotypes with few tassel branches resulting in reduced kernel set and the problem worsens under drought and low N stress. We recommend selection for shorter and lighter tassels to improve grain yield without compromising on tassel size to ensure sufficient pollen availability, especially under stress environments
Biopesticide treated double layered bags: novel method of application of botanicals for Sitophilus oryzae L. management in stored maize
Get PDFThis study was conducted in order to evaluate the efficacy of the novel method of application of leaf powder of Tinospora cordifolia as water-based paste between the layers of double layered storage bags and acetonic leaf extracts on single layered bags against Sitophilus oryzae to protect stored maize for a period of five months. Untre-ated double and single layered bags were set as controls. After 5 months of storage, the weevil population builds up, percent grain damage, and percent weight loss was significanly lower in T. cordifolia treated double layered bags @ 2.0% w/w. However, untreated single layered bags recorded high population build up and maximum percent grain weight loss. The present work suggests that T. cordifolia treated double bags provide better protection to maize from S. oryzae infestation up to five months and can be readily used as an alternative to synthetic pestici-des at the farm level
Bio-methane Production from Sorghum Elite Lines under the Climatic Conditions of Pakistan
Get PDFFossil foils are depleting dramatically to meet the ever blooming energy demands. Plant biomass is a best source
of renewable energy which can be used for bio-fuel production in order to meet the energy demands. Therefore,
this study was conducted for two consecutive years 2016 and 2017 to screen out best lines of sorghum for biomass
yield, chemical composition and bio-methane yield. The results revealed that tested lines had differential responses
for biomass yield, biomass quality and methane yield. Line 5018, performed remarkably and produced maximum
leaf area index (LAI), leaf area duration (LAD) and crop growth rate (CGR) followed by L-6024 whereas the minimum
LAI, LAD and CGR were recorded for L-5025. Maximum plant height, leaves per plant and dry matter yield ha-1 was
observed in L-5018, whereas the minimum plant height leaves per plant and dry matter yield ha-1 was recorded in
L-5025. Likewise, L-5018 also had maximum protein content, acid detergent fiber, neutral detergent fiber, lignin
content and ash content whereas the L-1914 had the minimum values for these parameters amongst the tested li-
nes. In addition, L-1914 produced maximum specific yield, however, L-5018 produced maximum methane yield ha-1
owing to higher dry matter yield ha-1. The results of this study suggested that L-5018 can be used to develop high
biomass cultivars with good methane yield potential
The role of dominant tree cover and silvicultural practices on the postfire recovery of Mediterranean afforestations
Get PDFFire is one of the major disturbance factors in Mediterranean-type ecosystems, where since long time man has deeply modified the natural fire regime. To know how woody species recover after fire is of prominent importance for understanding vegetation dynamics, as well as for the management of Mediterranean plantations, especially where broadleaved and coniferous trees coexist.Our research was carried out at Monte Petroso (Sicily), within an historical afforestation intervention in the Mediterranean basin. We assessed the post-fire response of mixed oaks and oak-pine afforestations within six experimental plots (two plots per homogeneous sector) differing in dominant tree species (Quercus ilex or Pinus pinea), time since last wildfire (1954 or 1982), and post-fire management (understory cleaning and removal of dead biomass or no management). Dendrometric surveys and phytosociological relevés were carried out to characterize the tree layers, the regeneration by woody species plus Ampelodesmos mauritanicus, as well as plant species richness. Our field surveys have confirmed a notably high resilience to fire by Mediterranean woody species, regardless of post-fire management practices. The dominant tree species played a significant role as Quercus ilex seems to foster stand development and the regeneration dynamics in the understory, especially that of Quercus pubescens. By contrast, Pinus pinea seems to slow down the regeneration by woody species, especially at higher stand density. Post-fire management practices seemed to favor mantle shrubs (Prunetalia spinosae) and grassland species (Hyparrhenietalia hirtae), while negatively affecting shrub species (Cisto-Ericetalia multiflorae). In presence of sufficient propagules of native woody species, the option of no management after fire has to be considered. The results of our research may be useful to improve the management of fire-prone Mediterranean plantations, taking into account the differences in plant strategies to cope with fire, as well as the dominant canopy
Use of Sentinel-2 for forest classification in Mediterranean environments
Get PDFSpatially-explicit information on forest composition provides valuable information to fulfil scientific, ecological and management objectives and to monitor multiple changes in forest ecosystems. The recently developed Sentinel-2 (S2) satellite imagery holds great potential for improving the classification of forest types at medium-large scales due to the concurrent availability of multispectral bands with high spatial resolution and quick revisit time. In this study, we tested the ability of S2 for forest type mapping in a Mediterranean environment. Three operational S2 images covering different phenological periods (winter, spring, summer) were processed and analyzed. Ten 10 m and 20 m bands available from S2 and four vegetation indices (VIs) were used to evaluate the ability of S2 to discriminate forest categories (conifer, broadleaved and mixed forests) and four forest types (beech forests; mixed spruce-fir forests; chestnut forests; mixed oak forests). We found that a single S2 image acquired in summer cannot discriminate neither the considered forest categories nor the forest types and therefore multitemporal images collected at different phenological periods are required. The best configuration yielded an accuracy > 83% in all considered forest types. We conclude that S2 can represent an effective option for repeated forest monitoring and mapping