The growth of sweet cherry cultivars Regina, Skeena and Sweetheart was evaluated when grafted onto the Edabriz rootstock and at four planting densities. The trial was set on March 2003 at four locations in the North and Centre of Portugal, with two replications in Caria, Vila Real and Alcongosta and three in Carrazedo de Montenegro. Within row spacing is approximately 5,0 m and plant spacing along the row is 0.7, 1.4, 2.1 and 2.8 m, corresponding to densities of 2600, 1300, 860 and 650 trees/ha, respectively. The trunk diameter of every plant was measured each year and trunk cross sectional area (TCSA) was calculated. At the end of the second leaf stage, significant differences in growth were already observable, concerning both trial location and plant density. The sweet cherry trees of the C. Montenegro trial grew 76, 36 and 9% more than those of Alcongosta, Vila Real and Caria, respectively, thus trial location accounted for 25% of the expected total variance. Plant density corresponded to 3% of the total variance, and the trees at 0.7 m grew 22% less than those the furthest apart. Results show that cultivars grew poorly when grafted onto this rootstock in Alcongosta and Vila Real. Therefore, in analogous situations, it is important to adjust water and nutrient supply to the specific requirements of the rootstock, so as to better manage vegetative growth and to prepare the trees for their major role: fruit yielding.

Budding height effect on sweet cherry (Prunus avium L.) growth was investigated using several rootstocks. In 1997, a nursery trial was set up that included 'Burlat', 'Summit' and 'Van' sweet cherries budded onto 'Edabriz', 'Gisela 5' and 'Maxma 14' rootstocks at 10, 20 and 30 cm above soil level and onto 'Cab 11E' and 'Mazzard' (P. avium) seedlings at 10, 30 and 60 cm above soil level. With those trees, an orchard trial was established in 1999 in three locations of northeastern Portugal. Trunk diameter was recorded at the 6(th) leaf (2003), and trunk cross-sectional area (TCSA) was calculated. Cherry tree growth varied with rootstock and budding level, but no significant differences were observed between cultivars. TCSA reduction on 'Edabriz', 'Gisela 51 and 'Maxma 14' was 28, 25 and 19%, respectively, when comparing budding at 10 and 30 cm. There was a reduction of 22% in the trees on 'Cab 11E', but only 5% on 'Mazzard', when comparing budding at 10 and 60 cm. Thus, by the 6(th) year, higher budding height decreased tree vigour in all locations and rootstocks, except 'Cab 11E', for which budding at 30 cm rather than 60 cm had a greater TCSA reduction (26%). Thus, budding height can contribute to control of tree cherry growth, helping to manage canopy size and crop accessibility.

In March 2003, a trial was established at four sites in the main Portuguese sweet cherry (Prunus avium L.) producing areas to monitor 'Sweetheart' and 'Skeena' tree growth on three rootstocks (Edabriz, Gisela 5 [Gi.5] and 'MaxMa 14') and four in-row plant spacing. The between-row distance was 5.5 m and in-row distances were 70, 140, 210 and 280 cm, corresponding to approximate densities of 2600, 1300, 860 and 650 trees/ha. Trunk diameter was measured at the end of the 2(nd) leaf, and ANOVAs were conducted on the values for trunk cross-sectional area (TCSA). Significant growth differences were detected for rootstock, location and plant spacing. The rootstock was the factor that influenced plant growth the most in all locations; the trees on 'MaxMa 14' had a TCSA of 21 CM, whereas those on 'Edabriz' and Gi.5 were only 59 and 45%, respectively, of the MaxMa value. The trees at Caria grew 7, 31 and 43% more than those at C. Montenegro, Vila Real and Alcongosta, respectively. 'Edabriz' reduced TCSA between 35% in Carrazedo de Montenegro and 46% in Caria, while Gi.5 reduced growth to 52% in Alcongosta and 60% in Caria. Trees at the highest density (2600/ha) had the greatest TCSA reduction (17%). Overall, TCSA consistently decreased with closer in-row tree spacing; the decrease was 24, 21 and 16% on 'MaxMa 141, Gi.5 and 'Edabriz', respectively. In summary, density affected growth reduction the most in trees planted at 70 cm because of the greater competition, mainly on the semi-dwarfing rootstock.

The sweet cherry (Prunus avium) cultivar 'Summit' still fits the standard of excellence for its typical characteristics, including large fruit size and cordate shape. This study was undertaken in Vila Real, northern Portugal, with 'Summit' scions raised in a nursery on five rootstocks. The orchard trials were set up in 1999, and tree growth, yield, and fruit size were monitored up to the 6th leaf. At this phase, the rootstock trunk cross-sectional areas (TCSAs) for Maxma 14, Cab 11E, Edabriz, and Gisela 5 were 79.7%, 60.2%, 37.9%. and 29.3% of that of Mazzard, respectively. Cumulative yield was higher on Gisela 5, but it did not differ significantly from Cab 11E. Maxma 14, Edabriz, and P. avium attained only 56%, 50%, and 36% of Gisela 5 cumulative yield per tree, respectively. This latter rootstock also induced higher cumulative yield efficiency when compared with the other rootstocks. Average fruit weight varied significantly according to year, rootstock, and year x rootstock interaction, which accounted for 62.6%, 13.2%, and 19.1% of the total variation, respectively. In 2002, it was Gisela 5 that permitted the cultivar to bear the best-sized fruits (9.8g), but in 2003 (6th leaf) this rootstock produced the lowest sized fruits (10.2g). Conversely, on Edabriz, Cab 11E, and P. avium average fruit weight increased 29%, 26%, and 24%, respectively. Trees on Gisela 5 had 5.6 leaves (190 cm(2)) per fruit, whereas on Edabriz, Cab 11E, and R avium they had 1.6, 2.3, and 6.4 times that value, respectively. Gisela 5 and Edabriz were very efficient in controlling vigour, having induced precocity and high cumulative yield efficiency. Leaf area/fruit ratio, however, limited fruit growth on Gisela 5, where initial high productivities demand appropriate tree nutrition to allow complete fruit, leaf, and limb growth and development on the current and subsequent season. Cab HE was not so precocious, but proved to be productive and induced the best fruit growth. Suitable cultural practices must be adopted to fit rootstock requirements to optimise the balance between yield, fruit size, and economic value, especially for the most dwarfing.

In the Trás-os-Montes region, almond orchards are usually planted in the dry soils on the upper valley of the Douro river and are typically cultivated under non-irrigated conditions, leading to low yields. This study aimed to compare the physiological responses of five almond varieties (Francoli, Ferragnès, Glorieta, Lauranne and Masbovera) growing under non-irrigated and irrigated conditions. In irrigated conditions, all cultivars had higher photosynthetic rates, with maximum rates in a range of 10–12μmol CO2 m−2 s−1. Study of daily photosynthesis (June–August) indicates that, irrigated plants showed maximal values at 11h (32°C), while in water stressed ones highest values were found at 9h (28°C). The irrigation induced an increase in photosynthesis of around 173% in Lauranne, 187% in Francoli, 204% in Glorieta, 266% in Masbovera and 331% in Ferragnès. In relation to values of water potential that allow half-rate of photosynthesis (ψw50), they were calculated as −2.95, −2.50, −3.10, −3.20 and −3.30MPa for Ferragnès, Glorieta, Masbovera, Francoli and Lauranne, respectively.

SUMMARY - This three-year study compared the use of ELISA and RT-PCR for identifying Prunus necrotic ringspot virus (PNRSV) and prune dwarf virus (PDV) on 175 leaf samples taken from trees maintained as a budwood repository for almond growers. The primers used for RT-PCR were based on DNA sequences that code for coat protein, and both viruses could be detected in the same reaction. For PNRSV, both ELISA and RT-PCR produced similar results, although RT-PCR was more consistent, and had the added advantage that plant material could be tested at any time throughout the growing season. For PDV, virus particles were not detected by ELISA, but were detected in low titre using a nested PCR technique. RT-PCR is used routinely now to index progeny developed each year by the Australian almond improvement program in place of both graft incompatibility using woody indicator species and ELISA.

To study the effects of rootstock and budding height on tree growth, 4 cherry cultivars ('Burlat', 'Van', 'Summit', and 'Saco')were chip-budded in August 1997 at 10, 20, and 30 cm above ground level on Tabel Edabriz, Gisela 5, and MaxMa 14, and at 10, 30, and 60 cm on CAB 11E and mazzard. After taking initial data on nursery performance, an orchard trial was set up at three distinct climatic sites similar to 50 kin apart in north-central Portugal: Braganca, Mirandela and Vila Real. Preliminary data at the end of the second year revealed treatment differences with regard to trunk girth, total stem length and number of shoots per plant, with similar effects at all three sites. Trunk girths on Tabel Edabriz, Gisela 5, MaxMa 14, and CAB HE were, respectively, 60, 58, 85, and 78% of that on mazzard. Tree vigor varied with budding height; in general, relative trunk diameter growth was inverse to tree budding height both in the nursery and the orchard. Relative tree height tended to increase with budding height of the vigorous rootstocks, but not the dwarfing rootstocks. Of the 4 cultivars, 'Saco' was significantly less vigorous than the others on all of the rootstocks, which probably was due to infection with viruses. This trial will continue to evaluate treatment differences as the trees mature and cropping begins.

Almond (Prunus dulcis Mill.) is one of the most widely planted tree crops in Trdsos-Montes. The production in this region represents 60% of the Portuguese almond production. In 1999 and 2000, a study was carried out aiming to characterize the production practices and culture in this region. The cultivars. grown in traditional farms are generally unique in Tras-os-Montes, and bitter almond seedlings have been traditionally used. Almonds are frequently grown side by side with olives and vines. Production practices are restricted to soil management, harvesting and pruning. In the last few years in Tras-os-Montes, large investments in more promising, modem planting areas have been made, taking the same care and preparation as for other fruit orchards. GF 677 is the most widely used rootstock and 'Ferragnes', 'Ferrastar', 'Ferraduel' and 'Guara', are the most representative cultivars. The results of this work reveal the importance of almond in the Tras-os-Montes region and support the potential for new areas of plantation in the future.

In Portugal, almond (Prunus dulcis Mill.) is a traditional crop with good possibilities in terms of production and fruit quality, especially in the Southern (Algarve and Baixo Alentejo) and Northern (Tras-os-Montes) regions. A study of the variability and relationship among our cultivars is important for the development of a breeding program and for the organisation and conservation of the collections maintained in Portugal. The genetic relatedness among 35 almond cultivars from Portugal, France and Spain, and 5 putative wild almond plants was estimated using RAPD, msp-PCR and AFLP markers. The analysis of the data obtained was performed using Dice coefficient and UPGMA clustering. Three different molecular techniques revealed high levels of polymorphism and were capable of resolving intervarietal differences. In the case of almond, msp-PCR seems to be a good option for varietal discrimination, due to its low costs, simplicity and reliability.

Diurnal courses in net photosynthetic rate (PN), stomatal conductance (gs), leaf water potential (ψ), internal CO2 concentration (ci), and water use efficiency (WUE) were studied as season progressed, in relation to environmental factors in field grown Prunus amygdalus. In sun leaves PN reached maximum between 09:00 to 11:00 h and subsequently declined when high temperature and low humidity occurred. An increase was observed late in the afternoon. A decrease in gs and ψ was found as season progressed in both years of measurements. In periods of high evaporative demand, ψ was very low, however, it did not explain the reductions of PN in all the three periods (spring, early and late summer). Midday depression of PN and gs seemed to be related with leaf temperature (Tl) and high irradiance. Increase in ci and F0 and decrease in Fv/Fm found between 12:00 and 14:00 h corresponded to the decrease in PN. Therefore, a transient modification of photosynthetic machinery might be considered. WUE was negatively correlated with vapour pressure difference of leaf to air, that decreased during the day. The September values, higher than in the previous months, were due to the lower seasonal decreases in PN than in gs.

Five cultivars of Prunus amygdalus Batsch (Ferragnes, Ferrastar, Marcona, Garrigues, and Non Pareil) grafted on two different rootstocks (Garrigues and GF677), and two cultivars (Ferraduel and Casa Nova) grafted on GF677, were grown for three years under rainfed conditions in an orchard in northeast Portugal. Net photosynthetic rate (PN), leaf conductance for water vapour (gs), leaf water potential (Ψ), instantaneous water use efficiency (WUE), and internal CO2 concentration (Ci) were measured at three periods of the growing season: spring, summer (June or July) and late summer (September) over two years. Ferraduel, Ferrastar, and Marcona presented the best performance in the periods when environmental conditions were not very hard (May or September). Casa Nova and Non Pareil were well adapted to high air evaporative demand, preventing the increase of leaf temperature (T1). Ferrastar, although having a good performance in May and September, did well adapt to hard climatic conditions in June 1994. In the following year, although it presented the highest T1, the values were not limiting (30.6 ± 2.1 °C), and PN was only decreased from May to July. Marcona was highly dependent on T1, but prevented its increasing. Garrigues showed lower PN in most measurement periods. GF677 frequently induced the highest PN, WUE, and Ψ. PN was mainly dependent on T1, radiation, Ci, month, and year. WUE depended on the same factors. Ψ depended mainly on gs, air temperature, month, and year.

SUMMARY - Daily and seasonal gas exchange of fourteen rainfed almond tree varieties grafted in GF677, six years old, was monitored in the field. Pre-dawn leaf water potential (ψ0) changed from about -0.5 MPa in May to ca. -1.2 MPa in October which shows a reduction in soil water availability despite some precipitation in the first days of October. As a consequence, net photosynthesis (Pn) and stomatal conductance (Gs) decreased in the same period for most varieties, although it did not in 'José Dias' and 'Duro d'Estrada'. Decreases in Pn and Gs were observed from morning to afternoon in both periods. Pn maintained reasonably high values after harvest (≥ ≥ ≥ ≥10 µmol/m 2 .s) in all varieties which can be ascribed to increases or maintenance of pressure potential in some varieties. Although low, the precipitation in the first days of autumn and the increases in soluble sugars and /or proline could have contributed to maintain plant water status and photosynthetic activity. Increases of WUEi were observed in 'Duro d' Estrada', 'Duro Italiano', 'José Dias' and 'Verdeal'. Overall, the Portuguese variety 'José Dias' showed the best photosynthetic performance.

SUMMARY - In Trás-os-Montes Region, almond orchards are usually planted in the dry soils of Upper Douro River Valley. Even so, they are traditionally cultivated under non-irrigated conditions, resulting in low and non- competitive production. This study aims to compare the physiological responses of five almond varieties ('Francolí', 'Ferragnès', 'Glorieta', 'Lauranne' and 'Masbovera') growing under non-irrigated and irrigated conditions and to find the specific leaf water potential value that maximizes the photosynthetic productivity. Under irrigated conditions, all the studied cultivars showed high photosynthetic potentials, with average daily rates in a range of 6.8 to 7.7 µmolCO2/m 2 /s. Under non-irrigation, plants showed a strong photosynthesis reduction of 32, 42, 47, 51 and 58% in 'Glorieta', 'Lauranne', 'Francolí', 'Masbovera' and 'Ferragnès'. This general reduction suggests the benefits of an adequate irrigation programme leaded by leaf water potential.

SUMMARY - In the nineties some new almond cultivars were introduced in Portugal but their characteristics were only described in the literature. In 1998 a field trial was established at "Centro Experimental da Terra Quente" (Quinta do Valongo, Trás-os-Montes) using some of the introduced cultivars: 'Francolí', 'Masbovera', 'Glorieta', 'Lauranne' and 'Ferragnès', grafted on GF-677 rootstock. The goals of this work were: (i) to evaluate the behaviour of foreign cultivars in comparison with 'Ferragnès', currently growing in Trás-os-Montes region; (ii) to determine the relative bloom and harvest dates; and (iii) to evaluate the kernel characteristics of the new cultivars. The results obtained from data collected in 2002 indicated that 'Lauranne' was the most productive with 5 kg/plant of nuts. Regarding vigour, recorded by measuring trunk diameter 20 cm above ground level, 'Francolí' was the most vigorous, with 81 mm. No differences were found for the blooming time among cultivars, except for 'Lauranne' that flowers 4 days after the others.