Miglioramento genetico per la produzione di seme in <i>Lolium perenne</i> L.

Attraverso due cicli di selezione fenotipica, condotti a piante spaziate, sono state ottenute, dalla varietà di Lolium perenne L. 'Vejo' due popolazioni migliorate per produzione di seme e peso di 1.000 semi. Scopo della ricerca è stato quello di valutare, in condizioni agronomiche appropriate, le popolazioni migliorate. La valutazione del materiale sperimentale ha interessato due distinte prove adiacenti: una a file è servita per valutare la produzione di seme, una a spaglio per valutare la produzione di foraggio. I risultati hanno dimostrato che il lavoro di selezione è risultato efficace soltanto per l'incremento del peso di 1.000 semi (+23%) mentre nessun guadagno è stato osservato nella popolazione selezionata per la produzione di seme. Two cycles of phenotypic selection of L. perenne cv. 'Vejo' were applied to improve seed prodution in one population and 1,000 seed weight in another. Selection was made on a spaced plants trial. The aim of the present research has been to evaluate the selected populations under appropriate agronomic conditions. Evaluation of both populations has been carried out in a specialized crop for seed prodution and in a sward for forage production. Results showed that seleetion was affective with respect to increase in 1,000 seed weight (+23%), while no results were achieved in selecting for high seed yield

Genetic Control of Parthenogenesis in Kentucky Bluegrass: Results from a Sexual x Apomictic Cross

Apomixis, as it exists in Poa pratensis L., permits to combine genotype fixation with propagation by seed. The process of apomictic seed production involves the formation of embryo sacs without meiotic reduction (apospory) and embryos without egg cell fertilization (parthenogenesis). Further information on the genetic control of apomixis was obtained by analyzing aposporous parthenogenesis and the segregation of molecular markers in a progeny resulting from a “sexual” (S) x “apomictic”(A) cross. Data from the 35 F1 plants examined so far have shown that parthenogenesis segregated 1:1, confirming control by a dominant gene, simplex in the parthenogenetic parent. Analysis of variance and regression were used to find single markers from the A and S parents affecting the trait in the 15 parthenogenetic progenies. A minimum of 4 genes from the sexual parent and 1 from the apomictic parent influencing the expression of parthenogenesis appeared to segregate in this cross

Molecular Characterization of Jatropha curcas Resources and Identification of Population-Specific Markers

Jatropha curcas L. is cited as one of the best candidates for future oil and biodiesel production. It is widespread in many tropical and subtropical countries but has not yet received much genetic improvement. The objective of this study was to collect Jatropha germplasm and characterize it with molecular markers. A total of 64 genotypes, collected from seven geographic locations on two continents, were analyzed with 32 simple sequence repeat and two candidate gene-specific primers (ISPJ-1 gene and Curcin-P2 gene promoter). In general, markers were found to be highly conserved, and many (40%) were monomorphic in the studied populations. Polymorphic primers, which amplified population-specific fragments, were identified. The polymorphic information content of the polymorphic markers ranged from 0.03 to 0.47. Genetic similarity analysis identified two distinct groups at 0.73 DICE similarity coefficient. Group I included germplasm collected from the islands of Cuba and Cape Verde, and group II consisted of Brazil, Mozambique, and Senegal populations. Island genotypes were found to be very distinct compared to their mainland counterparts. Sequencing of monomorphic fragments identified single nucleotide polymorphism (SNP) between these two groups. High-resolution melting analysis of the SNP in the Jcps9 locus further confirmed the two gene pools. Sequencing of polymorphic fragments of the Jc03 locus identified a deletion in a (GT)4 repeat motif in the genotypes in group II. Several population-specific microsatellites and SNP markers have been recognized. The distinct Jatropha genotypes and the population-specific molecular markers identified in this study will be valuable resources in breeding programs

Criteria for the Registration of \u3cem\u3eMedicago polymorpha\u3c/em\u3e L. and \u3cem\u3eLolium rigidum\u3c/em\u3e Gaud. Varieties in a Voluntary Register in Italy

Extensive and semi-extensive livestock systems in Southern Europe rely largely on permanent pastures, the productivity of which could be improved by sowing adapted species. Native forage species are a valuable tool for Mediterranean livestock production, owing to their specific adaptation to the harsh environment (featuring prolonged and severe spring-summer drought) and their generally good tolerance to grazing. Annual, self-reseeding species are able to cope with the prevailing drought stress by terminating the vegetative phase and setting seed before the onset of the stressful period, and enhance the durability of the sward by their self-reseeding capacity and subsequent seedling regeneration. Subterranean clover (Trifolium subterraneum L.) and medics (annual Medicago spp.) among the legumes, and annual ryegrass (Lolium rigidum Gaud.) among the grasses, are the most exploited self-reseeding species for pasture establishment

The Italian Catalogue of Herbage Varieties

With 3.4 million hectares, permanent grassland covers 25.8% of Italian U.A.A. (Usable Agricultural Area). Most of this is located in hilly and mountainous areas and is important for the stability of the soil even if their productivity is low. Alfalfa and annual forages cover 1.8 million hectares (C.R.P.A. 2010). Italy’s large longitudinal extension (between latitudes 35° and 47° N), delivers a great variety of climates (Fig. 1). The northern regions bordering the rest of Europe differ greatly from the southern regions surrounded by the Mediterranean Sea

COX, Harvey, Turning East : The Promise and Peril of the New Orientalism

Excessive soil salinity is a major ecological and agronomical problem, the adverse effects of which are becoming a serious issue in regions where saline water is used for irrigation. Plants can employ regulatory strategies, such as DNA methylation, to enable relatively rapid adaptation to new conditions. In this regard, cytosine methylation might play an integral role in the regulation of gene expression at both the transcriptional and post-transcriptional levels. Rapeseed, which is the most important oilseed crop in Europe, is classified as being tolerant of salinity, although cultivars can vary substantially in their levels of tolerance. In this study, the Methylation Sensitive Amplified Polymorphism (MSAP) approach was used to assess the extent of cytosine methylation under salinity stress in salinity-tolerant (Exagone) and salinity-sensitive (Toccata) rapeseed cultivars. Our data show that salinity affected the level of DNA methylation. In particular methylation decreased in Exagone and increased in Toccata. Nineteen DNA fragments showing polymorphisms related to differences in methylation were sequenced. In particular, two of these were highly similar to genes involved in stress responses (Lacerata and trehalose-6-phosphatase synthase S4) and were chosen to further characterization. Bisulfite sequencing and quantitative RT-PCR analysis of selected MSAP loci showed that cytosine methylation changes under salinity as well as gene expression varied. In particular, our data show that salinity stress influences the expression of the two stress-related genes. Moreover, we quantified the level of trehalose in Exagone shoots and found that it was correlated to TPS4 expression and, therefore, to DNA methylation. In conclusion, we found that salinity could induce genome-wide changes in DNA methylation status, and that these changes, when averaged across different genotypes and developmental stages, accounted for 16.8% of the total site-specific methylation differences in the rapeseed genome, as detected by MSAP analysis

Prime osservazioni su specie perenni ed annue autoriseminanti in vista della organizzazione di catene di foraggiamento in ambienti mediterranei

Nel corso del periodo 1987-89 sono state valutate le potenzialità produttive e la distribuzione della produzione di 32 tra ecotipi e varietà di graminacee e leguminose foraggere annue e perenni provenienti prevalentemente dall'Italia centrale. La prova è stata condotta contemporaneamente in tre ambienti appartenenti a diverse zone bioclimatiche dell'area mediterranea (Perugia, Grosseto e Sassari) utilizzando uno schema sperimentale a blocchi randomizzati con quattro ripetizioni. I rilievi effettuati hanno riguardato il ricopri mento specifico e la produzione di sostanza secca determinata con criteri differenti: mensilmente per le leguminose annue; al 50% della fioritura e quindi mensilmente per le leguminose perenni; all'inizio della spigatura e quindi mensilmente per le graminacee. Per le specie annuali oltre alla sostanza secca è stata determinata la produzione di seme. L'obiettivo è stato quello di caratterizzare materiali che possano essere impiegati scalarmente per dilatare il periodo di utilizzazione diretta al pascolo. Dai risultati è stato possibile individuare, a seconda delle località, alcune popolazione di Medicago polymorpha L., Trifolium subterraneum L. e Lotus sp. pl. che hanno permesso di anticipare il periodo di utilizzazione primaverile e prolungare quello autunnale. Su questa base sono stati ipotizzati esempi di catene di foraggiamento semplificate (a tre anelli). Per quanto concerne le specie annue autoriseminanti, esse sembrano poter svolgere un importante ruolo nella regolazione della distribuzione stagionale della produzione foraggera nelle due località caratterizzate da un clima più tipicamente mediterraneo (Grosseto e Sassari) mentre la produzione di seme è risultata più che soddisfacente per assicurare l'autorisemina in tutte e tre le località. During the period 1987-1989, the yield and the distribution of forage production of 32 ecotypes and varieties of annual and perennial forage Iegumes and grasses were evaluated. The origin of plant materials was CentraI Italy. The trial was carried out in three environments characterized by different Mediterranean subclimates (Perugia, Grosseto and Sassari). The experimental design was a randomized complete block with four replicates. Specific ground cover was assessed in fall 1987, 1988 and 1989. Dry matter yield was assessed: monthly for annual legumes; at 50% of flowering and then monthly for perennial legumes; at early heading and then monthly for grasses. Seed yield of annual species was also recorded. Aim of the trial was to characterize plant materials that could be utilized subsequently in order to extend the period of direct utilization of herbage by grazing animals. It was possible depending on localities, to identify some populations of Medicago polymorpha L., Trifolium subterraneum L. and Lotus sp. pl.. that allowed to bring forward the spring utilization and to extend the autumn utilization. On the basis of the resu1ts obtained, it was possible to set up some simplified forage chains. Annual self reseeding species seemed to be more important to improve seasonal distribution of herbages in the typical Mediterranean locations (Sassari and Grosseto). Seed production was more than appreciable in order to allow self reseeding at the three locations

Growing lettuce under multispectral light-emitting diodes lamps with adjustable light intensity

Light-Emitting Diodes (LEDs) technology offers vast possibilities in plant lighting due to its ability to mix different light frequencies, high energy use efficiency and low heat production combined to long lifespan. In particular, the combined effect of the Blue:Red (B:R) ratio and other frequencies in the central part of the PAR spectrum (CGA, i.e. cyan, green and amber) may be very important, though literature information is scarce. In this paper, the effects of six light spectra from LED technology were tested, i.e.: (i) B:R=0.82 (i.e. similar to sunlight) with CGA (treatment T0), (ii) B:R=0.82 without CGA (T1), (iii) red prevalence (B:R=0.25) without CGA (T2), (iv) blue prevalence (B:R=4) without CGA (T3), (v) red prevalence with CGA (T4) and (vi) blue prevalence with CGA (T5). The experiment was carried out in a walk-in climatic chamber with controlled temperature and relative humidity and an incident PAR photon flux density (PFD) of 300 μmol m–2 s–1 (14/10 light/dark photoperiod), generated by multispectral LED lamps with adjustable light intensity. Smooth leaved lettuce (Lactuca sativa L. cv Gentilina) was used as the test plant and biomass yield (DW, g m–2), LAI, soil coverage proportion (SC%), energy-biomass conversion efficiency (E-BCE, kWh g–1) and Radiation Use Efficiency (RUE, g mol–1 photons) were determined. Treatments with red predominance (T2 and T4) showed the highest SC% rates, while those with blue predominance (T3 and T5) showed the lowest. Light spectrum also affected leaf size (i.e. mean leaf area). The highest DW and RUE were observed in T2 and T4, followed by T0, while biomass in T3 and T5 was significantly lower (similar to T1). LAI values were generally high, but treatments with blue predominance showed the lowest LAI values (both with or without CGA). The introduction of intermediate wavelengths (green, cyan and amber) did not bring about significant improvement in DW or RUE, but resulted in reduced energy-biomass conversion efficiency, mainly due to lower architectural efficiency of the CGA LEDs. Future research should clarify how to optimise the light spectra according to the crop growth phases. The adoption of spectra promoting fast growth is fundamental in the early growth, while the use of spectra maximising yield quality may be more important later on

Produzione di seme di leguminose foraggere annuali in tre ambienti italiani

The seed production of 18 natural populations and varieties of annual forage legumes mainly collected in CentraI Italy have been evaluated in three Italian sites with contrasting climate and soil types. AlI species belonged to the genus Medicago and Trifolium. The experiments were carried out in Perugia, Grosseto and Sassari that belong to different bioclimatic zones of the Mediterranean area. The folIowing measurements were taken: seedlings establishment, monthly covering rate, seed yield and its components, percentage of hard seeds. The medics seed yields were not uniform between years particular1y in Perugia where the highest average yield was reached (800 kg ha-1) while the lowest one was recorded in Sassari (300 kg ha-1). A subclover seed yield of about 1600 kg ha-1 was recorded in Perugia in the first year. The persian clover was the highest yielding among the clovers with small seed size (1000-1600 kg ha-1). The seed yield components showed that the seed yield and the number of legumes per square meter were not always correlated. Seed hardiness increased going from humid to semiarid environments. The results show a good potential for annual legume seed yield in the Mediterranean environment. This is important either for the persistency by self reseeding of species to be included permanently in pasturelands and also for the seed production at a commercial level. Moreover, results point out that by exploring Italian genetic resources it is possible to find interesting genotypes to be inc1uded in a wide range of agricultural environments. In tre ambienti italiani con caratteristiche pedo-climatiche differenti sono state valutate le potenzialità produttive di seme di 18 popolazioni e varietà di leguminose foraggere annuali, appartenenti ai generi Medicago e Trifolium, provenienti in prevalenza dal Centro-Italia. La prova è stata condotta-contemporaneamente in tre località corrispondenti ad altrettante zone bioclimatiche dell'area mediterranea (Perugia, Grosseto e Sassari). I rilievi effettuati hanno riguardato l'insediamento, il ricoprimento specifico mensile, la produzione di seme e le sue componenti e la percentuale di semi duri. Le produzioni di seme delle mediche sono risultate oscillanti negli anni, avendo raggiunto al primo e al terzo anno valori più elevati che al secondo, in particolar modo a Perugia dove sono state ottenute le produzioni medie più elevate (800 kg ha-1) mentre le più basse sono state registrate a Sassari (300 kg ha-1). La produzione di seme di trifoglio sotterraneo ha raggiunto valori considerevoli a Perugia al primo anno (circa 1600 kg ha-1). Per quanto riguarda i trifogli a seme minuto, il trifoglio persiano ha manifestato un elevato potenziale produttivo al primo anno nei tre ambienti di prova (1000-1600 kg ha-1). Riguardo le componenti della produzione i risultati ottenuti hanno mostrato che non sempre esiste uno stretto legame fra produzione di seme e numero di infruttescenze per unità di superficie. La durezza dei semi è risultata via via crescente dall'ambiente umido a quello semi-arido e mediamente inferiore nel trifoglio sotterraneo rispetto alle mediche ed ai trifogli a seme minuto. I risultati ottenuti hanno evidenziato in generale buone potenzialità per la produzione di seme di leguminose annuali in ambiente mediterraneo. Questo aspetto riveste un'importanza duplice: per la persistenza per autorisemina di specie da inserire permanentemente nella flora dei pascoli, e per la produzione di seme su scala commerciale. Inoltre, i risultati indicano che dall'esplorazione delle risorse genetiche italiane è possibile individuare genotipi particolarmente interessanti per l'inserimento in un'ampia gamma di realtà agricole e ambientali