Tropic Beauty Research Articles

Cultivares e novas seleções IAC de pêssego para regiões de inverno ameno

Abstract Traditional peach production regions provide adequate chill for satisfactorily bud’s flower break dormancy, in cultivars there developed. However, considering the expansion of the orchards in mild winter areas and the expected global trends to warmer conditions, the local development of cultivars became relevant. Based on this background, this study proposed to evaluate the performance of 33 peach and nectarine cultivars and selections in mild winter climate. Features associated to the vegetative development, phenology, productivity and fruit characteristics were measured in nine seasons, and the data analyzed by multivariate analysis of variance. Significant correlations between features were remarked. The Pillai and F tests presented significant results, highlighting significant differences among cultivars for almost all features. Peach and nectarine genotypes showed genetic diversity that may be accessed for use as cultivars, or parental for crosses. ‘IAC Aurora 1’, ‘IAC Aurora 2’, ‘IAC Centenário’, ‘IAC Douradão’, ‘IAC Jóia4’, ‘IAC Ouromel 3’, ‘IAC Régis’, ‘Diamante’, ‘Eldorado’, ‘FlordaPrince’, ‘Premier’ and ‘Tropic Beauty’ were the cultivars with the best results. A large number of selections showed promising results, emphasizing, the ‘IAC 680-177’, ‘IAC 1085-27’, ‘IAC 785-9’, ‘IAC 2982-31’, ‘IAC 4682-45’and ‘IAC 6882-84’.

The Fruiting Wall: An Alternative Training System for Peach Orchards in Southeast Brazil

The choice of the training system is a key step to the establishment of new orchards since it affects yield and fruit quality. In this context, the aim of this study was to evaluate the performance of the scion cv. Tropic Beauty in the Fruiting Wall training system compared with the Y-Shaped. The two training systems showed no statistical differences among the years regarding the length of phenological cycles (approximately 140 days). The Fruiting Wall showed higher values for yield per tree (from 80.2 to 112.9%), fruit weight (from 7.6 to 10.3%) and fruit pulp from 9.4 to 12.6%) than Y-Shaped. The mean values for flesh firmness and fruit chemical characteristics ranged over the years for both training systems. Despite the lack of significant differences for fruit chemical characteristics, the observed values were compatible with those expected for the cultivar. Data collected from the Fruiting Wall showed lower variance than those collected from Y-shape. This suggests that the Fruiting Wall leads to a higher uniformity of production and fruit quality than the Y-Shaped. Based on these results, we concluded that the Fruiting Wall improves the peach cv. Tropic Beauty production, particularly for yield by tree and fruit mass.

Phenological growth stages and growing degree days of peach [Prunus persica (L.) Batsch] in sub‐temperate climatic zone of North‐Western Himalayan region using BBCH scale

AbstractIn this study, the phenological stages of peach have been described for the first time according to the BBCH scale (Biologische Bundesanstalt, Bundessortenamt and Chemische Industrie) and Baggiolini codes for five cultivars (Pratap, Tropic Snow, Tropic Beauty, Redhaven and July Elberta) in sub‐temperate region of India, which markedly differentiates vegetative and reproductive stages occurring in peach. The growing degree days (GDD) are the best indicators for monitoring the different phenological growth stages and were determined from dormancy breaking to fruit harvest when the cultivars reached maturity. Pratap, Tropic Snow and Tropic Beauty were identified as early‐season maturing with 814 ± 5.10, 996 ± 8.13 and 1004 ± 8.72 GDD, respectively. While, Redhaven was mid‐season cultivar with 1502 ± 16.17 GDD, and July Elberta was the late‐season cultivar with 1894 ± 6.00 GDD. Mid‐season cultivar Redhaven performed better in India's sub‐temperate region, accounting for higher yield (54.87 kg per tree), fruit length: diameter (1.11), TSS (12.26%) and total sugars content (10.26%). The description presented in the paper will act as a tool to provide a consensual unified approach for standardisation of phenological stages in peach and also for various cultural inputs and timely planning of harvesting. Moreover, the BBCH scale will act as a tool to assess the impact of climate change on crop phenology and to evaluate the adaptation of particular peach cultivars to different conditions.

Artificial neural network as an alternative for peach fruit mass prediction by non-destructive method

The mass and diameter traits of peach fruits are important parameters to define fruit quality, harvest planning, and management of peach production through the estimation of fresh mass. However, currently, fruit mass estimation methods are based on conventional destructive analyzes which, as they are invasive measurements, can take considerable time, in addition to being costly. Thus, this work aimed to use Artificial Neural Networks in the prediction of the fresh mass of peach fruits as an alternative to the destructive method. Fruits of the peach cultivars, 'Tropic Beauty' (G1), 'BRS Kampai' (G2), and 'BRS Rubimel' (G3) were used in the 2017 and 2018 harvests, and the cultivars (G1) and (G2) were used in the 2019 harvest. Fruits were individually measured for fresh mass (FM) (dependent variable), and suture diameter (SD), equatorial diameter (ED), fruit height (FH) (independent variables). Multiple linear regression analysis (R-MLM) and multilayer perceptron artificial neural network (ANN-MLP) were performed, involving the set of dependent variables SD, ED, and FH, all expressed as a function of the independent variable FM. In all scenarios, we observed that ANN_MLP was more effective than R-MLM in predicting FM. The best ANN-MLP was used to predict the mean peach fruit yield of the genotypes and also for their combinations in the 2018 and 2019 harvests. The presence of high values of R2 in the validation sample indicates that the trained network is efficient and has generalization power to predict FM in all situations evaluated. The use of neural networks to predict the fresh mass (FM) of the peach fruit is an alternative to conventional destructive analyzes and the chance to use the same neural network topology in consecutive harvests will allow the collection of data directly in the field, reducing the analysis time and costs.

Aquariums and Human–Animal Relations at the Great Barrier Reef


 
 In the early twentieth century, great delight in the unique tropical beauty of the Great Barrier Reef, coupled with an opportunistic spirit for commercial development, inspired the commission of eye-catching posters and advertisements by Australian tourist organisations. The aim of this article is to discuss a pictorial device that developed alongside the rise of modern tourist advertising images of Great Barrier Reef – a split-level viewpoint that approximates the effect of looking at the Reef through the glass sides of an aquarium. Building on my earlier research published in 2019 on wildlife photography and the construction of the Great Barrier Reef as a modern visual spectacle, and combining art history with environmental history, this article also turns to coloured advertising lithographs. It argues that split-level visualisations separate human from non-human and elevate the idea of human superiority. With the Great Barrier Reef facing unprecedented ecological pressures, the historical images at the centre of this article are instructive for understanding the deleterious effects of anthropogenic impact, as well as early twentieth-century attitudes towards human–non-human relations.
 

Effect of different modified atmosphere packaging and storage time on bioactive compounds in fresh-cut Tropic Beauty peaches

Modified atmosphere packaging (MAP) was evaluated for respiration rate, color, total phenolic content (TPC), antioxidant activity DPPH, flavonoids and pigments of fresh-cut Tropic Beauty peach. Modified atmospheres (21% O2 [Control], 5% CO2 [MAP1], 8% CO2 [MAP2] and 0% O2 [MAP3]) were evaluated for storing fresh-cut peaches for up to 10 days in temperatures of 5ºC. MAP significantly (p<0.05) affected the proprieties investigated as compared to control. Peaches with MAP3 have higher respiration(p<0.05) respiration rate than the peaches with the other treatments. Fresh-cut peaches in MAP2 showed more stable (p<0.05) carotenoid and anthocyanin contents, better attributes in the bioactive compounds. MAP1 and MAP2 exhibited better antioxidant proprieties at low storage temperature (5ºC) for up to 10 days storage and similar result was verified by principal component analysis used where modified atmosphere was observed as major factor.

Evaluation of phenotypic and biochemical diversity in peach (Prunus persica (L.) Batsch) and nectarine (Prunus persica (L) var nucipersica) cultivars in the subtropical region of Punjab

The experiment was conducted to find out phenotypic variability in cultural and biochemical fruit quality traits in peach [Prunus persica (L.) Batsch] and nectarine [Prunus persica (L.) var. nucipersica] during 2017 and 2018. The fruit length, fruit breadth and fruit weight; and fruit quality parameters, viz. flesh firmness, TSS, TA and ripening index were determined. Biochemical fruit quality traits such as ascorbic acid, total phenols, anthocyanins and relative antioxidant capacity were evaluated. Maximum fruit length (50.68 mm), total phenols (30.17 mg/100g FW) and relative antioxidant capacity (83.28%) was noted in Flordaglo, whereas, Tropic Beauty recorded maximum fruit breadth (55.17 mm), fruit weight (85.04 g), flesh firmness (14.74 lbf), ripening index (15.92) and ascorbic acid content (5.15 mg/100g FW). Maximum TSS (12.57° Brix) was noted in Florda Grand, while, minimum TA (0.78%) was recorded in Punjab nectarine. Cultivar Punjab Nectarine and Suncoast nectarine have maximum anthocyanin content (10.57 mg/100g FW). The cultivars exhibited wide phenotypic variation in cultural as well as biochemical traits. Such findings would be helpful in the future breeding programs for selecting cultivars having more health enhancing properties and good postharvest efficiency.

Response of peach tree leaf area to seasonal variation in tropical climate

Here, we describe differences in the establishment of the leaf limb area and morphology of peach tree attributed to different seasonal conditions at a high-altitude tropical climate. The cultivars ‘Tropic Beauty’, ‘BRS Kampai’ and ‘BRS Rubimel’ were cultivated in a production area located in Ervália – MG, Brazil. A series of experiments is being carried out in this area since 2016, and the data collection for the present report was carried out in the 2018 productive cycle, when the plants were 4 years old. Fully expanded leaves were collected from ‘brindilla’ type (with same flushes vegetative growth) branches according to the period of the year. Leaves were collected for two seasons in year, August (first flushes) and December (second flushes) 2018. Three hundred leaves from each cultivar at each season were collected randomly as representative of the canopy in its middle portion. They were separated into ten replicates and evaluated individually for length, width and leaf area. All cultivars exhibited cyclic and significant differences in length, width and leaf area attributed to the environmental conditions, where and when they were developed. Further investigation is needed regarding this differential leaf growth and its impact on the production of peach trees grown in tropical highland regions.

Y-shaped and fruiting wall peach orchard training system in subtropical Brazil

ASBTRACT Peach as commercial crop in Brazil is usually grown in open vase training system. However, in the 1970s large orchards changed to the Y-shaped system and higher density of plants. This system is the most used in Sao Paulo state because it allows orchard densification. However, the longevity of the trees is reduced from 15 to 8 years being the excessive exposure of internal branches to solar radiation the main reason for the reduction. Aiming to offer new alternatives of training system for peach, an experiment was carried out to evaluate the fruiting wall in comparison to Y-shaped, using the cultivar Tropic Beauty budded onto cultivar Okinawa. Ten plants by treatment were used as repetition and microclimatic equipment was installed inside the plant to measure temperature and solar radiation. Values of soluble solids (°Brix) were 9.64 to fruiting wall and 9.59 to Y-shaped, not statistically different. However most of fruit physicochemical characteristics were favorable to the fruiting wall system: fruit weight (g) – 97.56 and 90.44; pulp yield (g) – 92.42 and 85.70; pulp firmness (Kg∙cm–2) – 4.27 and 3.50; titratable acidity (g citric ac.∙100 ml–1) – 0.76 and 0.71; and ratio – 12.79 and 13.58, respectively to fruiting wall and Y-shaped. Solar radiation transmission and maximum daily temperature values for the Y-shaped were higher when compared to fruiting wall at harvest. The obtained data show that the fruiting wall training system could be an alternative to Brazilian’s growers for producing superior fruit quality without yield reduction.

Effect of Climate Change on Apple Productivity

India with its unique agro climate conditions favours cultivation of number of fruits. For decades together typical temperate fruits like apple, pear, stone and nut fruits were grown with adequate production and productivity. However, during the past 10-15 years on account of global warming many of the sites which were potential hub for temperate fruit cultivation have been rendering unfit for their cultivation. The productivity of temperate fruits especially apple in Himachal Pradesh is declining at a faster rate. Average yield of apple in India has been estimated at about 7.0 t/ha which is far below the level of 30 t/ha in most of advanced countries. The productivity has also not kept pace with the expansion in area under temperate fruits due to various biotic and abiotic problems faced by the farmers in the Himalayas. This has caused a serious concern not only to the hill farmer community but also to researchers, development agencies and policy planners. With the global warming, the decline in productivity is being mainly attributed to changing climatic scenario. It is clearly reflected that standard apple cultivar 'Starking Delicious' and 'Red Delicious' would not flower and fruit when chilling units are not adequately fulfil. Hence there is an urgent need to select appropriate low chill cultivars for plantation at low elevation location so that consistent yields are obtained and crop failures avoided. Results obtained revealed that cultivar 'Tropical Beauty' was the best genotype for the characters like plant height (6.60m), plant spread (5.67m), trunk girth (64.50cm), tree volume (111.20m3), leaf area (60.67cm2), number of fruit set per unit shoot length (15.25%), yield per plant (15.82Kg), fruit weight (129.80g), total sugar (8.48%) and non-reducing sugar (1.92%). Cultivar 'Parlin's Beauty' was the best genotype for characters like fruit breadth, reducing sugar and was recorded as promising next to 'Tropical Beauty' for many desirable traits. Cultivar 'Chahla' was superior for high number of flowers per unit shoot length, shoot length, fruit length and long duration of flowering. Earliest flowering was observed in cultivars 'Anna'. Maximum phenotypic coefficient of variability was observed for fruit yield per plant. High heritability and high genetic advance indicated presence of additive gene action for these traits. To meet the bulk requirements of the processing units and horticultural diversification, apple cultivation can be extended to mid hills by planting suitable low chilling cultivars. The low productivity of apple has become a serious concern for the farmers, research workers and development agencies at national and state level for the last two decades. Several factors can be attributed to the declining trend in productivity like expansion of apple cultivation to marginal areas, monoculture of Delicious varieties, declining standards of orchard management, improper chilling requirements and the fluctuating abnormal climatic conditions.

AVALIAÇÃO FÍSICA E QUÍMICA DE FRUTOS DE CULTIVARES DE PESSEGUEIRO

A avaliação da qualidade física e química de frutos de pessegueiro destinados ao consumo in natura varia entre safras. Essa variação depende, dentre outros fatores, das condições do local de cultivo. O objetivo deste trabalho foi avaliar a qualidade física e química de frutos de dezesseis cultivares de pessegueiro durante três safras em Viçosa-MG. As cultivares Aurora 2, Baronesa, Biuti, Colibri, Coral, Cristal, Delicioso Precoce, Flor da Prince, Joia 4, Lake City, Marli, Pérola de Iataquera, Rubimel, Talismã, Tropical e Tropic Beauty foram enxertadas sobre o porta-enxerto Okinawa no pomar experimental da Universidade Federal de Viçosa, em Viçosa-MG, no ano de 2008, e avaliadas quanto às características cor da casca (b* e h°), cor da polpa (b* e h°), massa do fruto (g), diâmetro polar (mm), diâmetro equatorial (mm), diâmetro sutural (mm), frmeza da polpa (N), teor de sólidos solúveis (oBrix), vitamina C (mg/100g), acidez titulável (% de ácido málico), carotenoides (mg/100g) e ratio (relação teor de sólidos solúveis e acidez titulável) durante as safras de 2011, 2012 e 2013. O experimento foi conduzido em delineamento inteiramente causalizado, com dezesseis tratamentos, três repetições e 10 frutos por parcela. Houve diferenças entre as características avaliadas nas três safras, sendo que a cultivar Floridaprince apresentou coloração mais intensa da epiderme bem como maiores teores de vitamina C.

Summer stratification and germination: A viable option for recovery of hybrid seedlings in low chill peach and nectarines

In-vitro embryo rescue; and summer stratification and germination under controlled conditions was tested for recovering hybrid seedlings in crosses involving low chilling peach and nectarines. The embryos from all the cross combinations showed very high in vitro embryo germination (>85%) on basal MS medium, which can be effectively performed at hard mature or full ripe stage. The stratification period of the hybrid seed varied from 36.3 days in Shan-i-Punjab × Florda Prince to 44.7 days in Tropic Beauty × Florda Grand. At the end of four weeks of transfering the cultures to culture room, maximum plant height (33.7 mm) was recorded in Shan-i-Punjab × Tropic Beauty, which did not differ significantly from the cross Florda Crest × Tropic Beauty. The fruit development period of the seed parent varied from 78.3 days in Shan-i-Punjab × Tropic Beauty and Shan-i-Punjab × Florda Prince to 104.7 days in Tropic Beauty × Florda Grand. Stratification media of cocopeat + vermiculite + perlite (2:1:1) resulted in the highest seed germination but, the actual germination percentage varied with cross combinations. Highest germination (81.5%) was recorded in the cross FlordaGlo × Tropic Sweet, which did not differ significantly from Tropic Beauty × Florda Grand. It was followed by seed germination (68.0%) in Florda Grand × Tropic Beauty. Under high density nursery system, the hybrid seedlings of FlordaGlo × Tropic Sweet showed highest growth (160 cm) and branches (13). The germination of hybrid seeds was positively correlated (0.86) with fruit development period of the seed parent (FDP) and negatively correlated (−0.85) with chilling requirement of seed parent. The proportion of rosseted seedlings was negatively correlated with FDP (−0.61) and positively correlated (0.39) with chilling requirement of the seed parent. The cross combinations with higher FDP of seed parent resulted in higher seed germination of hybrid seed. Hence, controlled climate stratification and germination after harvest can be a viable option for recovery of hybrid seedlings and reducing the breeding cycle in crosses involving seed parents with higher FDP.

Qualidade pós-colheita de oito variedades de pêssego

The fruit physical and chemical characteristics can vary during the maturation period and this variation depends, among other factors, on the weather conditions during fruit development. This study aimed to evaluate the changes in physical and chemical characteristics of eight peach cultivars during two seasons. The cultivars Campinas 1, Coral, Maciel, Marli, Premier, Regis, Rei da Conserva and Tropic Beauty were planted on Okinawa rootstock at the experimental orchard of the Federal University of Viçosa (UFV), Viçosa-MG, Brazil, in 2008 and the following characteristics were evaluated: fruit weight, skin color, firmness, soluble solids, titratable acidity, ascorbic acid and total carotenoids. The experiment was conducted during 2011 and 2012 growing seasons in a completely randomized design with eight treatments (cultivars), three repetitions and 10 fruits per plot. There were differences between the variables for the two seasons, with the largest variations observed for firmness, ascorbic acid and total carotenoids. Cultivars Maciel and Marli produced fruit with higher mass, Tropic Beauty with greater firmness and Rei da Conserva, Coral and Marli with higher soluble solids contents. The cultivar Rei da Conserva presented higher values for most of the evaluated variables in both seasons. The yellow color, evaluated by the hue angle, is associated with total carotenoids content in peaches.

Base temperature as a function of genotype: a foundation for modeling phenology of temperate fruit species

To complete each phase of the growing season, plants must accumulate thermal time at lower base temperature (Tb). Little information exists on Tb variation between either fruit species or cultivars of the same species. We therefore aimed to determine the lower base temperature for contrasting genotypes in precocity of peach, plum, grape, pear, and kiwi. Twigs 25-35 cm long for the following cultivars: peach, Tropic Beauty (TB) and Eragil (ER); plum, Gulf Blaze (GB) and Letícia (LE); grape, Chardonnay (CH) and Cabernet Sauvignon (CS); pear, Smith (SM) and Packham’s (PA); and kiwi, Golden King (GK) and Hayward (HA) were collected in orchards in Veranópolis, RS Estate, on 06/13/2014, with 0 h at temperatures ? 7.2°C (chilling hours; HC) in the field. Intact twigs packed in black plastic film were subjected to 1,008 HC at 0°C in incubators to overcome dormancy and then transferred to temperatures of 2, 4, 6, 8, 10, and 12°C on single-node cuttings planted in phenolic foam to define effective heat temperature for the genotypes. Over 110 d, budburst of the buds was evaluated in 2-3-d intervals in the green-tip stage. The resulting inverse data of number of days to budburst (1/days to budburst) was inserted into regression curves to estimate Tb for each genotype. Historical phonological series comprised of 10 years for the analyzed cultivars and meteorological data of the cultivation sites were used to determine thermal time (degree-days) for the fruit trees during the growing season, considering different phenological phases. Temperate fruit species exhibited different Tb behaviors: Tb was lower for early cultivars (TB and GB = 2.2°C; CH = 2.1°C; SM = 4.4°C; GK = 4.3°C) and higher for late cultivars (ER = 6.3°C; LE = 6.2°C; CS = 4.3°C; HA and PA = 8.2°C) for all cultures. The Tb f fruit cultivars related directly with genotype chilling requirements: the higher the chilling requirement, the higher the Tb of the cultivar. Cultivars of the same fruit species yielded a sum of degree-days almost equal to finalize the growing season, regardless of the degree of precocity (TB = 1720; ER = 1801; GB = 1680; LE = 1718; CH = 2310; CS = 2369; SM = 2096; PA = 2003 GD; GK = 2775; HA = 2691). Regarding phenological phases, 82% of the assessed cases responded more to thermal time (degree-days) than to chronological time (d) to complete phenological steps. Differences in Tb between genotypes are a relevant factor for improving the accuracy and applicability of phenology models in agriculture.

Variation in Tree, Foliage, Phenological and Pollen Characters of Low Chill Peach Germplasm Accessions under Mid-hills of Himachal Pradesh

The present investigation was carried out in the department of Fruit Science, Dr Y S Parmar University of Horticulture and Forestry, Nauni, Solan, HP, India. Ten peach genotypes namely Tropic Sweet, Saharanpur Prabhat, Earli Grande, Flordaprince, Tropic Snow, Flordaglo, Valle Grande, Tropic Beauty, Pratap and Florda Grande were evaluated for their tree, foliage, floral and pollen characteristics. Valle Grande recorded maximum tree height (2.73 m) whereas, minimum tree height (1.83 m) was recorded in Flordaprince. Shedding of leaf started from 29th October (Tropic Sweet) and extended till 20th November (Tropic Beauty). Time of full bloom extended from 24th January in Saharanpur Prabhat and Pratap to 2nd February in Tropic Snow and Flordaglo. The longest duration (39 days) of flowering was recorded in Pratap and shortest (28 days) in Tropic Sweet and Earli Grande. Pollen viability ranged from 93.82% to 98.93% when tested by 1.0% acetocarmine and 84.19 to 97.70% by 0.1% erythrosin B. In vitro pollen germination varied from 62.26% to 90.39%.

Adaptability and stability of fruit set and production of peach trees in a subtropical climate

Brazilian peach breeding programs have been established to improve peach [Prunus persica (L.) Batsch] production, yield consistency, quality, and disease resistance. Every year several genotypes are selected and their traits must be assessed. This study aimed to evaluate adaptability and stability of fruit set and production of peach genotypes in a subtropical climate, using the GGE biplot methodology. The experimental design was completely randomized with three replicates (trees) in a factorial arrangement of 29 × 3 for genotype and growing season, respectively. The genotypes 'Conserva 1129', 'Rubimel', 'Kampai', 'Tropic Beauty', and 'Cascata 967' had the greatest adaptability and stability for fruit set. The genotypes 'Conserva 681', 'Santa Aurea', 'Atenas', 'Kampai', 'Cascata 962', 'Tropic Beauty' and 'Cascata 967' had the greatest production adaptability and stability. The GGE-biplot methodology classified the peach tree genotypes with regard to adaptability and stability of fruit set and production.

Caracterização de frutos de cultivares de pessegueiro na Zona da Mata Mineira

This study aimed to evaluate physical and chemical characteristics of fruits of 14 peach cultivars with yellow flesh named Aurora 1, Aurora 2, Biuti, Capdeboscq, Campinas 1, Diamante, Douradão, Dourado 1, Lake City, Maciel, Rei da Conserva, Régis and Tropic Beauty. They were introduced in the experimental orchard of the Federal University of Viçosa (UFV), Viçosa-MG. The experiment was conducted during the 2011 season, in a completely randomized design with 14 treatments (cultivars), three replications and 10 fruits per plot. Fruit with more intense yellow skin coloration were found in cultivars Lake City and Régis and the cultivars Aurora 1, Aurora 2, Capdeboscq, Diamante, Douradão, Dourado 1, Maciel, Régis and Tropic Beauty had yellow flesh color more intense. The fruits of cultivars Capdeboscq, Maciel and Rei da Conserva had, in general, higher fruit weight and diameter. The fruits of cultivars Douradão and Dourado 1 had a better balance between acidity and soluble solids and higher content of vitamin C. Higher levels of carotenoids were found in cultivars Capdeboscq, Campinas 1, Régis and Rei da Conserva.

Produção e qualidade dos frutos de cultivares e seleções de pessegueiro na Serra da Mantiqueira

Objetivou-se avaliar a produção e atributos de qualidade de cultivares e seleções de pessegueiro nas condições da Serra da Mantiqueira. Um ensaio de competição foi implantado no município de Maria da Fé (MG), com 17 cultivares e seleções ('BRS Libra', 'Bolinha', 'Fla 88-13', 'Ouromel-2', 'Aurora-1', 'Jade', 'Aztec Gold', 'Tropical Beauty', 'Sensação', 'Chimarrita', 'Diamante', 'Maciel', Conserva 1122, Cascata 1015, Conserva 1050, Conserva 693 e Cascata 1056). O experimento foi implantado em 2006, no espaçamento de 6,0x4,0 m, com mudas enxertadas no porta-enxerto 'Okinawa'. As avaliações foram realizadas em três ciclos produtivos (2009, 2010 e 2011), analisando-se os aspectos fenológicos, produtivos e atributos de qualidade do fruto. Para 'Bolinha', Cascata 1015, 'Ouromel-2', Conserva 1050 e 'Tropical Beauty' não se observou alternância de produção. 'Ouromel-2', Conserva 1050 e 'Tropical Beauty' tiveram maior produção de frutos, com colheitas concentrando entre 13 de outubro e 16 de novembro. A cultivar Ouromel-2 teve atributos de qualidade mais adequados para o consumo ao natural, com menor acidez, boa firmeza de polpa e sólidos solúveis mais elevados. Conserva 1050 é boa opção para a indústria e 'Tropical Beauty' para dupla finalidade.

BREEDING LOW-CHILL PEACHES IN SUBTROPICAL QUEENSLAND

The low-chill peach (Prunus persica (L.) Batsch) breeding program at Maroochy Research Station, Nambour, Queensland was initiated in 1996 in response to industry requests for new peach and nectarine cultivars adapted to subtropical Australia. The program aims to develop a range of high quality peach and nectarine cultivars with both melting and non-melting flesh, with chilling requirements of 100 to 400 chill units (CU) but an emphasis on 150 CU or less. The program's breeding strategies have included collection and evaluation of germplasm from Australia, Europe, America and Asia, hybridisation with the industry standard 'Tropic Beauty' peach, inter-crossing of subtropical and temperate parents and incorporation of non melting flesh. Fruit characteristics being selected are large size, high flavour, firm flesh and early ripening. Important tree characteristics being selected are low chilling requirement, moderate crop load and compact tree habit. Over 20,000 seedlings have been produced and 53 selections propagated for second stage evaluation. Three peach and two nectarine selections have been released for large scale evaluation from 2006 to 2009.

Basal temperature and thermal sum in phenological phases of nectarine and peach cultivars

The objective of this work was to evaluate basal temperature, thermal sum at different phenological stages, phenological phase duration, yield and seasonality of one nectarine and 14 peach cultivars, between 2006 and 2009. The considered phenological phases were: pruning-sprouting; sprouting-flowering, from swollen bud to open flower; flowering-fruiting, from petal fall to medium-sized fruit; and ripening. Minimum basal temperatures (Tb) obtained were: pruning-sprouting, 8°C, irrespective of the cultivars; sprouting-flowering, 10°C, except for 'Cascata 968', which required 8°C Tb; flowering-fruiting, 12°C, except for 'Oro Azteca', which required 14°C Tb; ripening, 14°C, except for 'Sunblaze', 'Diamante Mejorado' and 'Precocinho' with 12°C Tb. For most cultivars, the maximum basal temperatures were 30, 34, 34 and 28ºC for phases pruning-sprouting, sprouting-flowering, flowering-fruiting and ripening, respectively. 'Turmalina', 'Marli' and 'Tropic Beauty' showed average yields of 3,945.0, 3,969.3 and 3,954.0 kg ha-1, respectively, in 2009, while the nectarine 'Sunblaze' showed around 3,900 kg ha-1 in 2008 and 2009. The cultivars differed for their total cycle and for the accumulated thermal sums which varied, respectively, from 245 days and 1,881.4 degree-days for 'Oro Azteca', to144 days and 1,455.7 degree-days for 'Precocinho'.