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‘Andes-1’ is an early clingstone peach [Prunus persica (L.) Batsch] (21 d before ‘Carson’) with yellow flesh, constant productivity, and high fruit quality both for canning and for fresh consumption (Fig. 1). The fruit shows an attractive red covering color, reaching 60% of the skin surface with no red coloration in the flesh which could affect the quality of the canned product.
Citation: HortScience horts 46, 3; 10.21273/HORTSCI.46.3.499
‘Andes-1’ resulted from a cross made in 1998 at Santiago, Chile, between the Californian clingstone peach ‘Andross’ (University of California, Davis, 1964) and the selection A1-5A-85 from the Australis® breeding program (a cooperative peach breeding program between the University of Chile and Andes Nursery Association). The main objective of Australis® for peaches and nectarines is the development of high-quality-yielding early- or late-maturing cultivars, which could be stored for at least 35 d in cold storage keeping a high flavor quality. Genotypes are intended to be grown in the central zone of Chile and other areas with a Mediterranean climate with medium chill requirements accumulation from 1 May to 15 Aug., ≈1000 chilling units according to the Utah model (Richardson et al., 1974).
‘Andes-1’ was selected after 4 years of field evaluation in the progeny plot and later tested on small plots of 15 trees budded on ‘Nemaguard’ rootstock. The experimental plots were established in Paine (long. 33°48′14.85″ S, lat. 70°40′6.54″ W) and El Tambo (long. 34°28′21.77″ S, lat. 70°59′21.22″ W), two representative environments of the Chilean stone fruit production area. Data were collected from the experimental plots for additional 5 years.
‘Andes-1’ is a medium-sized tree of low vigor, medium-sized leaves with a short petiole and e-glandular, showing no susceptibility to mildew in the local conditions, and average cultivation management. The flower is a non-showy type, and the flower density is rather low, which permits quick thinning labor.
‘Andes-1’ under local experimental conditions blooms in the same period as ‘Andross’.
A trial for determining the effect of crop load on yield and fruit quality of ‘Andes-1’ was performed on 4-year-old trees planted at a spacing of 5 × 3 m and trained as Ypsilon. Six fruit-load levels were established by hand thinning to an average spacing of 5, 10, 15, 20, 25, and 30 cm between fruit before pit hardening. To standardize tree size, the fraction of the intercepted photosynthetically active radiation (PAR f), which corresponds to the fraction of the whole radiation that is effectively intercepted by the canopy, was determined at harvest by three measures during a whole solar day (Reginato et al., 2007). The standardized production efficiency can be expressed as kilograms of fruit per square centimeter of trunk branch cross-sectional area (Robinson et al., 1991). This index permits to compare on the same base, different canopy's shapes or orchard densities. The PAR f varied between 0.63 and 0.73 among trees. The fruit load varied from 12.0 fruits per intercepted square meter for the heaviest thinned tree to 29.5 fruits per intercepted square meter for the least thinned tree, respectively. A linear relationship (R2 = 0.95) between yield efficiency, expressed as kg/intercepted m2, and the fruit load was found. From these values, and projecting an orchard with 80% interception of solar radiation coverage, the expected average fruit size and yield are 100.2 g and 23 t·ha−1, respectively, for the less thinned trees.
Because thinning increases size and weight fruit but diminishes total production (Crisosto et al., 1997; Link, 2000), a balance between production and fruit size is necessary (Day et al., 1993). When the average separation of fruit was 5 to 10 cm along the bearing shoot, the fruit weight reached average values of 100 g, whereas when the separation averaged between 25 and 30, the weight was close to 150 g (Table 1). For the canning industry, fruit of 100 g meet the minimum size standards. An average fruit weight of 110.4 g was obtained when yield efficiency is 2.6 kg/intercepted m2.
At harvest performed when the ground color changed from green to yellow–green, similar hue values were obtained for all thinning intensities, confirming the similar coloration among all the harvested fruit (Table 1). The flesh firmness ranged between 29.0 and 45.6 N, which was within the range suggested by the canning industry; however, higher firmness was observed in fruit harvested from low-load trees (i.e., 5 and 10 cm between fruit). Thinning intensity has an effect mainly on fruit size and harvest maturity, which among other factors are associated to the determination of flesh firmness at harvest (Link, 2000). The soluble solids concentration (SSC) varied between 10.6% and 12.5%, which is considered adequate for peaches for fresh consumption (Crisosto et al., 2006). SSC is a parameter probably not related to fruit load (Table 1), as described by Link (2000). The same situation was observed in titratable acidity in which values ranged between 0.30% and 0.65%. These values are considered low compared with traditional peach cultivars (Crisosto and Crisosto, 2005). The variation of acidity within the same cultivar was almost imperceptible to consumers, although they were able to discriminate among different cultivars according to acidity (Crisosto et al., 1997). A consumer preference test conducted after 3 d of ripening at 20 °C indicated that the fruit is appreciated by consumers with 80% of the ratings being “I like it somewhat” to “I like it very much.” Furthermore, no symptoms of chilling injury were observed (Crisosto et al., 1999), reaching after 22 d at 0 °C plus 3 d at 20 °C, 17.8 N flesh firmness and 10.7 °Brix, and after 30 d at 0 °C plus 3 d at 20 °C, 14.2 N flesh firmness and 12.5 °Brix.
Molecular characterization was done using microsatellites [simple sequence repeat (SSR)], following Narváez et al. (2000) methodology. The following 12 highly informative SSR markers were used, as described by Rojas et al. (2008) for peach fingerprinting: CPPCT 022, BPPCT 001, CPPCT 029, CPPCT 030, BPPCT 008, PMS67, BPPCT 007, BPPCT 038, BPPCT 026, BPPCT 034, BPPCT 039, and UDP 96-005. It was observed that for all the markers evaluated, ‘Andes-1’ carried one allele from each parent (Table 2) with likelihood for this coincidence of 1.49 × 10−5, confirming ‘Andross’, and ‘A1-5A-85’ as parents of ‘Andes-1’. This allelic pattern study constitutes a nice tool for differentiate new genotypes with a very low probability of confusion.
For budwood availability, please contact Mrs. Karin Sonneborn from Andes Nursery Association (ksonneborn@anachile.cl).
Contributor Notes
We thank Pedro Martínez-Gómez for his help in the redaction of this paper.
To whom reprint requests should be addressed; e-mail rinfante@uchile.cl.
