1,721,135 research outputs found
Innovation in pear management techniques
No full textWhile most temperate fruit crops appear to undergo very dynamic changes in cultivars, rootstocks, yields, etc., pear seems to be the slow and least changing one. Opposite to other crops, whose yields have been steadily increasing over the last 50 years, pear shows very little variation in productivity over this timespan. Pear breeding has specific challenges, which are reflected in the comparatively low number of new cultivars released over the years. Pear genetics being more “static” than other species, in most pear growing areas a leading cultivar, or just a handful are grown and, in several cases, this number has decreased, such as in Italy, where about 70% of pear orchards are now represented by ‘Abbè Fetel’ alone. Case in point, their average yields are the same as those reported in the late 1940s for this cultivar, although rootstocks, training systems and densities may be quite different. To top it off, novel diseases and disorders have arisen, that also compound the problematic situation. However, this needs changing, if growers' bottom line is to be preserved. Pear lends well to training according to novel 2-D orchard designs, is amenable to mechanical pruning, and could benefit from other innovative orchard management techniques that are applied to apple and/or peach, in the context of Precision Orchard Management. These include autonomous vehicles, fixed point spraying systems, IoT configuration of irrigation/fertigation systems, stronger and wider connections between pre- and postharvest, including the use of Artificial Intelligence applications
The effect of defruiting at different stages of fruit development on leaf photosynthesis of 'Golden Delicious' apple
No full textNet photosynthetic rates (A) of leaves on 11-year-old, field-grown apple trees (Malus domestica Borkh. cv. Golden Delicious) were measured after removal of fruits at four different stages of development. Defruiting decreased A by 21, 42, 27 and 7% when fruits were growing at 311, 293, 229 and 113 mg(DW) day(-1), respectively. Photosynthesis was inhibited more in the afternoon than in the morning, but it was not affected during the first 8 h after fruit removal. Inhibition of A was positively correlated with crop sink strength, but it was not correlated with fruit relative growth rate or crop load. Defruiting decreased A at saturating irradiances (PPFD > 1000 mu mol m(-2) s(-1)), but did not modify the apparent quantum yield of single leaves. These results suggest that the overall effect of defruiting on carbon fixation is negligible in dense canopies, but it may be significant in sparse canopies and in single shoots
Tree architecture, flowering and fruiting - Thoughts on training, pruning and ecophysiology
No full textTraining and pruning protocols are developed to improve orchard profitability, especially yield quantity and quality, and regular bearing. This paper gathers two sets of results in the apple. At the whole-tree scale, we showed that the training system efficiently affects fruit quality in a given year, but its effect on regular bearing depends on cultivar. These results together with a common expertise developed in past experiments and in private orchards suggest that there are 'plastic' cultivars for which usual pruning and training protocols are able to improve regular bearing, and 'nonplastic' cultivars for which alternate bearing is less influenced by pruning and training. At the shoot scale, the relationships between the length of a shoot and the frequency of terminal flowering and fruiting strongly suggest that all relations between vegetative and reproductive growth should clearly distinguish flowering and fruiting. Indeed, flowering appears more genotype-dependent than fruiting. These findings have consequences on the way we prioritize research on tree structure and function. Most ecophysiological studies of sink-source relationships in fruit-trees are strongly influenced by models developed in annuals. They implicitly assume a competitive balance between vegetative growth and fruiting, and strive to achieve high partitioning of carbon to the fruit. In fruit-trees with complex architectures such as the apple, and especially for cultivars with an alternate-bearing pattern, vegetative growth can be completely decoupled from fruit production in the off-year. Our objective would rather be to take into account the uniqueness of the fruit-tree, emphasizing the need for collaborative works between morphologists and ecophysiologists on the one hand, and geneticists and breeders on the other hand, with research focused on allocation to bud organogenesis and return-bloom which is a prerequisite for fruit production
Particle film technology: Approach for a biorational control of Cacopsylla pyri (Rhynchota Psyllidae) in Northern Italy
No full textTwo trials were carried out to investigate the efficacy of a kaolin-based product (Surround WP) a white non-abrasive, finegrained alluminum-silicate mineral in controlling pear psylla Cacopsylla pyri (L.) oviposition. The trial was carried out in Italy's Emilia-Romagna Region on cv. Abbé Fétel during late winter in 2001-2002 year; the reference product was mineral oil. The timing of product application was before or at the onset of egg laying during overwintering. The results show a very good efficacy of kaolin in comparison to the mineral oil and untreated control. No eggs were found on the treated plants and no phytotoxic effects were observed. No nymphs were observed inside the flowers in the kaolin-treated plots
Single leaf and whole canopy gas exchange of pear as affected by graft incompatibility
No full textLeaf and whole-canopy gas exchange of Beurré Hardy and Beurré Bosc trees, either selfrooted or grafted on clonal quince rootstocks (BA29 and MC), and a common seedling were measured to study the effect of varying degrees of graft incompatibility on tree gas exchange. Whole-canopy gas exchange was expressed in terms of the energy absorbed by the canopy, which was measured at hour intervals using a custom-built sensor. Leaf transpiration, stomatal conductance and net photosynthesis were not affected by cultivar, but they were reduced by the dwarfing quince rootstock, MC. Similar results were obtained for daily patterns of whole-canopy photosynthesis, measured in early July and August. The ratio of leaf net photosynthesis to light intercepted per tree followed the same pattern as whole-canopy photosynthesis
WHOLE CANOPY GAS EXCHANGES AND LIGHT INTERCEPTION OF THREE PEACH TRAINING SYSTEMS
No full textCanopy photosynthesis (A(c)), transpiration (E-c) and light interception of three peach training systems, delayed vasette (DV), palmette (P), and Y-trellis (Y), were measured by a whole-canopy gas exchange open system, and a custom-built all-wave scanner-recorder, Whole-canopy assimilation rates peaked before midday in both DV and P, then A, started to decrease in the afternoon, even if light was not a limiting factor. Both canopies reached similar maximum E-c rates in late afternoon. On the contrary, A(c) of the east and west sides of the Y was nearly constant between 10:00 and 15:00 hours.In DV and P, the assimilation-transpiration ratio (ATR) decreased from early morning hours to a minimum in early afternoon, increasing thereafter. In the Y, ATR values were higher than in DV and P and, after the initial morning decrease, they remained stable until the end of the day. On a hectare base, light interception in DV and P was similar, while Y showed higher interception throughout the day. Whole-canopy photosynthesis was linearly related to the amount of light intercepted by the tree
Shoot type and light exposure influence carbon partitioning in peach cv. elegant lady
No full textCarbon partitioning and translocation in one year old fruiting limbs of 'Elegant Lady' peach (Prunus persica L. (Batsch)) was studied, as affected by source (leaves on actively growing extension shoots (EXT), leaves on lateral shoots at nodes carrying (F) or not carrying (NF) fruit), and by light regime (full sun or 5 d 70% shade conditioning), five times during the season (2, 4, 7, 11, 17 weeks after full bloom (WAFB)). Growing shoot apices were the strongest sinks early in the season (2 WAFB), with the EXT apices capable of attracting more carbon (C) and over longer distances, than the NF or F ones. The major source of newly synthesized carbohydrates for fruit growth 2 WAFB was the F lateral shoot, i.e. the most important C contributor for fruit growth well into stage II (11 WAFB in this study). EXT shoots began contributing to fruit growth before the NF shoots: 4 WAFB on, they exported to the fruits in amounts similar to the F shoots. This contribution was even larger 17 WAFB, when the F shoots retained more C than the other two shoot types. The NF shoots exported to growing apices 2 WAFB, but export decreased 4, 7, and 11 WAFB, compared with the other treatments. NF shoots contributed to fruit growth in the same amounts as the EXT shoots 17 WAFB, and more than the F shoots. Shade did not consistently affect patterns of carbon partitioning within limb components, except for the F treatment, where it diminished C export to the fruit in the first four treatment dates. Partitioning within fruit components (mesocarp, endocarp and seed) followed the fruit growth curve, with more C allocated to endocarp tissues at 11 WAFB (stage II). Results are in agreement with, and substantiate, earlier findings concerning the effects of fruit position on the limb, and competition for carbon with active vegetative sinks on fruit development
The palmette training system
No full textThe palmette system became successful because it improved orchard productivity by inducing earlier bearing and enabling higher planting densities than other contemporary systems, and also because it allowed the use of harvesting platforms, which reduced costs by greatly facilitating pruning and picking in comparison to open-centre trees.The palmette is best suited to medium-high planting densities (700-1,100 trees/ha in peach, and 1,500-2,000 in standard apple cvs.), with tree heights ranging from 2.5 m (apples on weak rooststocks) to over 4 m (peach in fertile soils). Because the Palmette system "squeezes" trees along the row, this system is not suitable for very high planting densities. When trees are planted too close, they lose production on the lower tier of branches to self-shading. Wherever a vigor-controlling factor is available (e.g. growth habit, rootstock, growth retardants, low-vigour environment, or combinations of them), the palmette may be less suitable than the slender spindle, low vase or even Y-trellis. By the same token, however, it is still widely used in deep, fertile soils for those species whose vigor is more difficult to control (e.g. peach, plum, apricot, pear on seedling). The modern palmette is a far cry from the original concept. Because of cost considerations it is currently developed as freely as possible (minimizing pruning, and thus improving early yield) in the first 3-4 years, given the constraint that a hedgerow must be formed. It is more labor-intensive to establish than other systems land requires trellising) but it is less expensive to maintain once the tree is formed
Red and blue netting alters leaf morphological and physiological characteristics in apple trees
Full text linkThere is little information about the role of red and blue light on leaf morphology and physiology in fruit trees, and more studies have been developed in herbaceous plants grown under controlled light conditions. The objective of this research was to evaluate the effect of red and blue screens on morpho-anatomy and gas exchange in apple leaves grown under ambient sunlight conditions. Apple trees cv. Fuji were covered by 40% red and blue nets, leaving trees with 20% white net as control. Light relations (photosynthetic photon flux density, PPFD; red to far-red light ratio, R/FR and blue to red light ratio, B/R), morpho-anatomical features of the leaf (palisade to spongy mesophyll ratio, P/S, and stomata density, SD) and leaf gas exchange (net photosynthesis rate, An; stomatal conductance, gs; transpiration rate, E; and intrinsic water use efficiency, IWUE) were evaluated. Red and blue nets reduced 27% PPFD, reducing by 20% SD and 25% P/S compared to control, but without negative effects on An and gs . Blue net increased gs 21%, leading to the highest E and lowest IWUE by increment of B/R light proportion. These findings demonstrate the potential use of red and blue nets for differential modulation of apple leaf gas exchange through sunlight management under field conditions
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