1,721,101 research outputs found
Relationships between spur- and orchard-level fruit bearing in almond (Prunus dulcis)
No full textAlmond is often considered to be a moderately alternate-bearing species but historical yield data typically do not exhibit clear patterns of alternate bearing at the orchard level, while research has indicated that spurs (the main fruit bearing unit in almond trees) rarely produce fruit in two subsequent years. The objective of the present work was to analyze the bearing behavior of almond trees at both the orchard level and the individual spur level over multiple years to explain this apparent paradox. The 10-year yield patterns of three almond cultivars grown at three different sites within California were analyzed for tendencies of alternate bearing at the orchard level. At the individual spur level, data on spur viability, and number of flowers and fruits per spur were collected on 2400 individually tagged spurs that were observed over 6 years to characterize bearing at that level. At the orchard level one cultivar (Nonpareil) did exhibit a tendency for alternate bearing at one site (Kern) but other cultivars and sites did not. The orchard and the individual trees in which the spur population study was conducted showed tendencies for alternate bearing but the spur population did not. Only a relatively small percentage of the total tagged spur population bore fruit in any given year and therefore while individual fruiting spurs exhibited a high level of non-bearing after fruiting the previous year the spurs that did produce fruit in any year generally did not constitute enough of the total spur population to exhibit alternate bearing at the whole population level. Our results suggest that annual bearing fluctuations in almond are probably mainly due to year-to-year variations of parameters affecting fruit set and that high rates of fruit set in a given year may involve a larger-than-normal percentage of a spur population in fruit bearing. This would limit the size of the spur population available for flowering in the subsequent year and could cause alternate year bearing. However, from historical records, this would appear to be the exception rather than a normal circumstance. Therefore, almond should not be considered to be a strictly alternate-bearing species
Relationships between flower density and shoot length in hazelnut (Corylus avellana L.)
No full textHigh flower density is a prerequisite to obtain high yield. Considering that flower induction occurs simultaneously with shoot growth, shoot length could influence shoot flower abundance. Previous studies reported that nuts were borne in the apical part of the canopy on long shoots. But no data have been reported about possible relationship between flower density and shoot length. The aim of the present work was to assess whether flower density is related to shoot length in Corylus avellana L. Shoot morphological characteristics, flower number and flower sex was studied in two of the main cultivars of C. avellana. Female flowers were generally borne in apical long shoots. Shoot length was negatively correlated with flower density even though different behavior was observed between cultivars. Maximum estimated probabilities of shoot flowering varied between cultivars. These results suggest that flower density can be influenced by shoot length. Genotype can also affect such relationship. Flower density appeared to decrease in longest shoots in hazelnut. The effect of genotype on flower density may explain variation of productivity between cultivars
Trunk constriction effects on vegetative vigour and yield efficiency in olive tree (Olea europaea L.)
No full textTree vigour is one of the most important issues in super-high density olive orchards (~1,600 tree ha-1). Tree vigour could be limited by horticultural practices such as pruning and fertilization but such practices have a limited effect and increase growing costs. The aim of this work was to test a new technique based on the application of a constriction to the trunk in order to obstruct the flow of sap in xylem and phloem. To this end, on 5 cultivars trained in a super-high density olive orchard in Central Italy, constrictions were applied by a plastic strap in 2009 and 2010, and were removed at the end of the following year. At the end of the experiment, constricted trees had smaller vegetative growth than the control trees. During the first experiment (2009), in the constriction year, yield efficiency was higher in constricted trees. In the second year, low vigour cultivars (‘Arbequina’, ‘Maurino’ and ‘Moraiolo’) had a consistent reduction of yield, while vigorous cultivars (‘Leccino’ and ‘Frantoio’) had similar yield but a slightly increased yield efficiency. No effect was detected in fruit characteristics, but the oil phenol content was higher in the constricted trees. In the second year experiment (2010), similar results were obtained, but yield efficiency increase and vegetative growth reduction were lighter because the trees were one year older than those of 2009 experiment. Trunk constriction was a successful technique for reducing tree vigour and enhancing tree yield efficiency, especially in vigorous cultivars
Evaluation of canopy elasticity, light penetration and reciprocal shading for optimal canopy management in high density hedgerow olive orchards
No full textCanopy management is one of the most important factors influencing yield and economic life of high density hedgerow olive orchards. Currently, the canopy volume is set mainly on the basis of size of over-head harvesting machines; this is a limit for natural growth of trees which have to be pruned hard once the allotted canopy size is reached. Thus, in these sorts of orchards, growers have to find the optimal canopy management in order to control canopy growth and keep the canopy productive (high-yield efficiency). Three main factors have to be considered in canopy management: adaptation of canopy to over-head harvesting machines, light penetration and reciprocal shading. Over-head harvesting machines require elastic canopy in the part exceeding the projection of conveyor frames. Pruning operations have to be set in order to eliminate branches which are not elastic enough to bend down. Elasticity requirements were calculated in 'Arbequina' and 'Maurino' and branch sizes in relation to their branching position are discussed. Light penetration influences the light environment experienced by each shoot. Light environment influences flowering potential of bearing shoots. Effects of selective pruning and topping on light penetration in the canopy of 'Arbequina' and 'Maurino' are compared. Canopy size effect on shading of nearby row was then studied and compared between rows pruned by topping cuts and selective side pruning. In conclusion, tree canopy size can be increased but pruning should keep canopy elastic and enough porous in order to allow light penetration and flowering in the whole canopy volume. Increasing canopy size does not increase significantly reciprocal shading between rows but at the same time it may allow to keep fruit yield steady once tree canopy fills the allotted space
Performance and oil quality of 'Arbequina' and four Italian olive cultivars under super high density hedgerow planting system cultivated in central Italy
No full textSuper high density (SHD) olive has been introduced in Italy, mainly in the southern regions (flat areas of Apulia and Sicily), in the middle of 2000s, using only three cultivars of low vigour: 'Arbequina', 'Arbosana' and 'Koroneiki'. Since the limited cultivar choice is still considered one of the main issue for SHD in central Italy, a comparative trial was set up in 2006 to evaluate the suitability of 4 Italian olive cultivars to a planting density of 1667treesha-1. Vegetative vigour, productivity and oil quality were evaluated for four local cultivars ('Frantoio', 'Leccino', 'Maurino' and 'Moraiolo') in comparison with the standard 'Arbequina'in a SHD orchard. 'Frantoio' and 'Leccino' were more vigorous than 'Arbequina' and 'Maurino'; the most precocious were 'Arbequina' and 'Maurino', and the most delayed 'Frantoio'. After 8 years form plantation, 'Arbequina' and 'Maurino' provided significantly higher accumulated yield when compared to 'Leccino'.Considering all the vegetative tree characteristics (canopy volume, trunk section area and removed wood by pruning) the most vigorous cultivars were 'Frantoio' and 'Leccino'. The crop efficiency of 'Maurino' was similar to that of 'Arbequina' and higher than those of the other 3 Italian cultivars. Concerning the oil quality, the highest phenols content was recorded in 'Frantoio' and 'Leccino' oil; the lowest in 'Arbequina' oil. On the contrary 'Frantoio', 'Leccino' and 'Moraiolo' had the highest oleic acid contents while 'Arbequina' and 'Maurino' had similar values. Polyunsaturated fatty acid content was significantly higher in olive oil from 'Maurino'. To conclude we can say that 'Maurino', showing low vegetative vigour and compact growth, early and high yield, adaptation to mechanization, good oil quality and shelf life, resulted to be the most suitable cultivar for SHD system in this trial
Efficienza di raccolta e trasmissione della vibrazione in oliveto superintensivo raccolto con macchina scavallatrice
No full textNegli oliveti superintensivi la raccolta meccanica viene effettuata con macchine scavallatrici derivate dalle vendemmiatrici. Queste applicano la vibrazione direttamente sulla parte di chioma esterna da cui viene trasmessa al resto della pianta. Lo scopo del lavoro era quello di studiare la trasmissione delle vibrazioni all'interno della chioma e di verificare se differenti frequenze e volumi potessero influenzare negativamente l'efficace trasmissione della vibrazione. Confrontando diverse tesi, i risultati hanno mostrato che volumi di chioma maggiori possono essere raccolti efficacemente dalle macchine a tutt'oggi disponibili, anche se i risultati acquisiti indicano che l'invecchiamento delle piante e il progressivo irrigidimento potrebbero causare la riduzione dell'efficienza di raccolta soprattutto nelle porzioni di chioma più basse e interne
Relationship among shoot productivity, light penetration in the canopy and tree light interception in super – high intensive orchards.
No full textAPPLICAZIONE DELLA PIEGATURA NELLA POTATURA DI OLIVETI SUPERINTENSIVI
No full textNel 2010-2011, in Centro Italia è stata valutata l‟influenza di due tecniche di potatura sulcontrollo dell‟attività vegetativa, sul mantenimento di un‟elevata superficie fogliare e sull‟efficienza della raccolta in continuo degli oliveti superintensivi su duevarietà, Arbequina e Moraiolo, differenti per portamento.Una tecnica, indicata con il termine “potatura”, consisteva in operazioni di taglio mediante forbici, volta ad eliminare branchette mal posizionate, succhioni, rami eccessivamente verticali, rami posti al di sotto di 50 cm; l‟altra, “piegatura”, consistevanell‟applicazione di una minima potatura e nella inclinazione e piegatura dei rami verso l‟interno del filare, usando come sostegno i fili della struttura. La tecnica di potatura ha significativamente influenzato la vigoria delle piante; infatti, dopo unanno dall‟intervento, sono stati asportati circa 1,8 kg di materiale vegetale dalle piante sottoposte a potatura con tagli cesori rispetto ai 0,6 kg dalle piante piegate. La tecnica di potatura non ha influenzato i volumi delle chiome, ma ha condizionato la produzione di olive per pianta. Le piante “piegate” hanno prodotto 4,7 kg di olive contro i 4,2 kg delle piante “potate”. Questo comportamento si può spiegare con il maggiore equilibrio vegeto -produttivo riscontrabile negli olivi “piegati”, che, infatti, tendono a produrre meno materiale vegetativo.La velocità di raccolta con scavallatrice è risultata pari a 2,1 km /h, con valori leggermente minori nelle piante sottoposte a piegatura rispetto a quelle potate. I danni alle piante sono risultati contenuti, rispetto a quanto osservato in altri impianti, senza differenze tra le tecniche di potatura e tra le cultivar. In aprile 2011, le piante delle due tesi in ambedue le varietà hanno mostrato un‟elevata fioritura.I risultati hanno indicato che la piegatura permette un migliore controllovegetativo eun aumento della produttività degli oliveti superintensivi, grazie al raggiungimento e/o al mantenimento di un maggiore equilibrio vegeto –produttivo
PRIMI STUDI SULL‟AUTOCOMPATIBILITA‟ ED INTERCOMPATIBILITA‟ DELLE CULTIVAR RUSTICA E GENTILE DELL‟AQUILA COLTIVATE IN ABRUZZO
No full textIn Abruzzo, in provinciadi L‟Aquila, in un‟area a ridosso del Monte Morrone, in Valle Peligna, nel 2011 è stata condotta un‟indagine per studiare il grado di compatibilità delle due cultivar di olivo maggiormente diffuse nella zona in esame: la „Rustica‟ e la „Gentile dell‟Aquila‟. Obiettivo del lavoro è di verificare il grado di autocompatibilità e di intercompatibilità delle due cultivar al fine di migliorare la produttività olivicola del territorio. Per la realizzazione della prova, prima della fioritura, si è proceduto all‟isolamento di branchette fiorifere, opportunamente scelte, tramite sacchetti di carta. Al raggiungimento di circa il 70% di fioritura dell‟intero oliveto, su alcune branchette è stato effettuato lo scambio dei sacchetti per controllare l‟impollinazione incrociata tra le cultivar in studio e verificarne la compatibilità; su altre branchette non è stato effettuato lo scambio per rilevare l‟autoimpollinazione delle singole cultivar e verificarne quindi il grado di autocompatibilità. Nella prova il controllo era rappresentato da branchette fiorifere lasciate alla libera impollinazione. Per le singole cultivar ogni tesi è stata ripetuta 6 volte. Ad allegagione avvenuta ed ad intervalli di tempo di circa 20 giorni è stato effettuato il conto dei frutti. In attesa diulteriori conferme, da questi primi rilievi emerge che le cv Rustica e Gentile sono compatibili tra loro. La cv Rustica risulta essere autoincompatibile mentre la cv Gentile dell‟Aquila ha mostrato in alcune ripetizioni una parziale autocompatibilità. Ulteriori indagini sono quindi necessarie per definire se la cv Gentile dell‟Aquila possa essere autocompatibile o meno e se l‟utilizzo nelle coltivazioni di altre varietà possa incrementare l‟allegagione di queste due cultivar autoctone
Pruning technique in young high density hedgerow olive orchards
No full textIn young high density hedgerow olive orchards tree canopies do not suffer of reciprocal shading and lack of light penetration. When canopies are small and trees are fast growing, high yield efficiency can be obtained. On the other hand, considering that canopy volume at maturity is constrained by the harvesting machine size and canopy shading, some growers try to slow down vegetative growth in order to delay problems due to excessive canopy growth. The aim of the present work was to determine if and, eventually, what kind of pruning has to be applied in young high density hedgerow orchards. In an 'Arbequina' high density hedgerow olive orchard planted in 2006, two different pruning techniques (removal of basal canopy (T1) and removal of basal canopy+hedging (T2)) were compared with non-pruning in 2009. Unpruned trees resulted more productive than T1 and T2 trees because of the removal of bearing shoots in T2 and T1. T2 increased shoot growth and stimulated vegetative growth. Canopy efficiency was larger in non-pruned trees, but harvesting efficiency resulted larger in pruned trees because of the removal of bearing shoots in portions of the canopy which were not harvested by the over-head harvester. Minimal pruning operations have to be applied in young high density hedgerow olive orchards. At this stage, pruning operations have to be limited to the removal of canopy portions not harvested by over-head harvester
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