Studies on the expression of morphological characters of some Romanian peach varieties

 Corresponding author: Ligia ION Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Studies on the expression of morphological characters of some Romanian peach varieties Florentina Maria Dumitrescu 1, Dorel Hoza 1, Daniel Nagy 2, Claudia (Modoran) Bododel 1 and Ligia Ion 1, * 1 Faculty of Horticulture, University of Agronomic Sciences and Veterinary Medicine of Bucharest, 59 Marasti Blvd, District 1, Bucharest, Romania. 2 Faculty of Management and Rural Development, University of Agronomic Sciences and Veterinary Medicine of Bucharest, Romania. World Journal of Advanced Research and Reviews, 2025, 27(01), 2051-2058 Publication history: Received on 11 June 2025; revised on 20 July 2025; accepted on 22 July 2025 Article DOI: https://doi.org/10.30574/wjarr.2025.27.1.2713 Abstract In Europe, PPV (Plum pox virus) is by far the virus with the greatest impact on the Prunus genus and the most limiting factor in peach culture from economic point of view. The sharka virus is causing big damage and losses not only for apricot crops but as well for all other Prunus species. Varieties with genetic resistance to disease are a major pursuit in amelioration programs. Identifying new genotypes with natural resistance to PPV creates new premises and possibilities for obtaining varieties that better meet current and future market requirements. In this paper the peach varieties Alexia, Alex, Flacăra and Triumf, are initially evaluated for morphological characters, followed by the most important results to be proposed in spring in the new hybridization programs. Given the character's heredetry and the way parental forms behave throughout the selection process, the final objective (obtaining superior varieties) is based on the new characters' heredetry. Key words: Characters; Peach; Varieties; Amelioration; Virus; Resistance. 1. Introduction The sensibility of varieties to disease attacks and the need for costly phytosanitary treatments that at the same time, have major repercussions both on the environment and on human health are vital problems that must be the central aim of sustainable technologies [1]. Genetic amelioration is a means of conscious change of genotypes for the benefit of the cultivator and the consumer. The collection, preservation and rational use of the peach germ cell fund is a basic condition for the successful amelioration of the new varieties [2]. The identification, creation and introduction into culture of new genotypes with genetic resistance to diseases, but also of high biological and nutritional value is the main way of qualitative and quantitative amelioration of plants [3]. Resistance is an all-embracing term used when the plant undergoes the stress caused by the pathogen without being affected both qualitatively and quantitatively. This type of situation is encountered if the host plant contains a resistance gene and the pathogen that infects it contains the corresponding viral gene [4]. World Journal of Advanced Research and Reviews, 2025, 27(01), 2051-2058 2052 Establishing definitive parasitic relationships between the two partners (the virus and the host plant) implies the existence of certain properties [5], that each gives the ability to act and react as a prerequisite for establishing ecological balance, cohabitation in case of sensitive plants or blocking the activity of the pathogen in the case of resistant plants. The essential condition for a pathogen to parasite a plant, is the existence of a mutual affinity. If the pathogen permeates the plant and the infection occurs, the plant is susceptible to the pathogen. If the infection does not occur after the pathogen infects the plant then the plant is resistant to the pathogen [5]. In order to identify potential genitors, it is necessary to evaluate morphologically and phenotypically the existing germplasm fund as well as to study the variability of these characters and to establish the correlations between the main features and characters [7]. The negative effects of the use of pesticides, and in particular of environmental pollution and waste accumulation, as well as increasing practical difficulties in solving disease control problems, have been linked to the widespread and sometimes abusive use of pesticides, consequances that have strengthend research into the identification and selection of varieties resistant to diseases, pests and their use in breeding programs [8]. 2. Material and methods Observations, measurements and determinations were performed on each variety in 2018 on: phenology (bloom, harvest, maturation stage) and morphological characteristics. The varieties study was carried out according to the CPVO Testing Protocol (Comunity Plant Variety Office), TP / 053/2 Rev [8]. The method use to observe the characteres is the following: • MG – single measurement of a group of plants or parts of plants; • MS – measurement of a number of individual plants or parts of plants; • VG – visual assessment by a single observation of a group of plants or parts of plants; • VS - visual assessment by observation of individual plants or parts of plants. By type of expression the characteristics can be: • Qualitative characteristics, QL, are those characteristics expressed by discontinuous stages. These stages are self-explanatory and independently significant. All steps are required to describe the full level of character, and each form of expression can be described in a single step. These characters are not influenced by pedo-climatic conditions (for example, ovary pubescence: absent (1), present (9)); • Quantitative characteristics, QN, are those characteristics whose expression covers the entire range of variation from one extreme to the other. Expression can be recorded on a one-dimensional, continuous or discrete linear scale. The range of expression is divided into a number of stages for the purpose of describing (for example, the size of the fruit: very small (1), small (3), medium (5), large (7), very large (9)). The division aims to offer, as far as practicable, a uniform distribution across the scale. • Pseudo-qualitative characteristics, PQ. In the case of pseudo-qualitative characters, the expression range is at least partially continuous but varies in more than one dimension (for example, color of the fruit: not visible (1), green (2), cream green (3), greenish white (4), cream white (5), cream (6), pink white (7), greenish yellow (8), cream yellow (9), yellow (10), orange-yellow (11) , in which case it can only be properly described by defining two ends of the linear range. Each individual stage of the expression needs to be identified to describe the proper level of character. 3. Results and discussion Characteristics with an asterisk (marked with *) are characters of particular importance for the international harmonization of descriptions, being invariable, regardless of pedo-climatic conditions. Expression levels are indicated for each characteristics to facilitate the harmonization of descriptions. Each level of expression is assigned a numerical equivalent for ease of data recording (Table 1) World Journal of Advanced Research and Reviews, 2025, 27(01), 2051-2058 2053 Table 1 Results concerning the level of expression of characteristic on peach varieties CPVO No. Obs. Method Characteristic The level of expression of characteristic Note Alex Alexia Flacăra Triumf Alex Alexia Flacăra Triumf 1. G QL VG Tree: size medium medium large medium 5 5 7 5 2. QN VG Tree: vigour medium medium strong medium 5 5 7 5 3. QN VG Tree: habit upright to spreading upright to spreading upright to spreading upright to spreading 3 3 3 3 4. QN VG Flowering shoot: thickness medium thick medium medium 5 7 5 5 5. QN VG Flowering shoot: length of internodes medium medium medium short 5 5 5 3 6. QL VG Flowering shoot: presence of anthocyanin coloration present present present present 9 9 9 9 7. QN VG Flowering shoot: intensity of anthocyanin coloration weak medium medium medium 3 5 5 5 8. QN VG Flowering shoot: density of flower buds dense medium medium medium 7 5 5 5 9. G QL VG Flower: type rosette rosette campanulate campanulate 2 2 1 1 10. PQ VG Corolla: main colour (inner side) medium pink medium pink dark pink medium pink 4 4 5 4 11. PQ VG Petal: shape broad eliptic circular narrow elliptic narrow elliptic 2 3 1 1 12. QN VG/ MS Only variety with flower type campanulate. Petal: width - - narrow narrow - - 3 3 13. QN VG/ MS Only varieties with flower type: rosette. Petal: width broad broad - - 7 7 - - 14. QL VG Flower: number of petals five five five five 1 1 1 1 15. QN VG Stamen: position compared to below below below below 1 1 1 1 World Journal of Advanced Research and Reviews, 2025, 27(01), 2051-2058 2054 petals 16. QN VG Stigma: position compared to anthers same level same level above above 2 2 3 3 17. QL VG Anthers: pollen - present - present - 9 - 9 18. QL VG Ovary: pubescence absent present present present 1 9 9 9 19. QN VG/ MS Stipule: length medium long long medium 5 7 7 5 20. QN VG/ MS Leaf blade: length medium medium medium medium 5 5 5 5 21. QN VG/ MS Leaf blade: width medium medium medium medium 5 5 5 5 22. QN VG/ MS Leaf blade: ratio length/width medium high medium medium 5 7 5 5 23. QL VG Leaf blade: shape in cross section convex convex convex convex 3 3 3 3 24. PQ VG Leaf blade: margin crenate shallow serrate shallow serrate crenate 1 2 2 1 25. QN VG Leaf blade: angle at base acute acute acute acute 1 1 1 1 26. QN VG Leaf blade: angle at apex small small small medium 3 3 3 5 27. PQ VG Leaf blade: colour green green green green 2 2 2 2 28. QL VG Leaf blade: red mid-vein on the lower side absent absent absent absent 1 1 1 1 29. QN VG/ MS Petiole: length medium scurtă medium medium 5 3 5 5 30. QL VG Petiole: nectaries present present present present 9 9 9 9 31. QL VG Petiole: shape of nectaries reniform reniform reniform reniform 2 2 2 2 32. QN VG Fruit: size medium medium large large 5 5 7 7 33. PQ VG Fruit: shape (in ventral view) broad oblate circular ovate circular 1 3 4 3 34. VG Fruit: absent absent present present 1 1 9 1 World Journal of Advanced Research and Reviews, 2025, 27(01), 2051-2058 2055 QL mucron tip at pistil end 35. QN VG Fruit: shape of pistil end (without mucron tip) weakly pointed pointed pointed weakly pointed 4 5 2 1 36. QN VG Fruit: symmetry (viewed from pistil end) symmetric asymmetric asymmetric symmetric 2 1 1 2 37. QN VG Fruit: prominence Of suture medium medium medium medium 5 5 5 5 38. QN MS/ VG Fruit: depth of stalk cavity medium deep deep deep 5 7 7 7 39. QN MS/ VG Fruit: width of stalk cavity medium medium broad medium 5 5 7 5 40. PQ VG Fruit: ground colour of skin greenish white cream white yellow yellow 3 4 9 9 41. QN VG Fruit: relative area of over colour of skin medium large medium large 5 7 5 7 42. PQ VG Fruit: hue of over colour of skin light red medium red dark red medium red 4 5 6 5 43. PQ VG Fruit: pattern of over colour of skin striped mottled spots mottled 2 4 3 4 44. QL VG Fruit: pubescence of skin present present present present 9 9 9 9 45. QN VG Fruit: density of pubescence medium very sparse medium medium 5 1 5 5 46. QN VG Only varieties with fruit pubescence: absent: Fruit: glossiness - - - - - - - - 47. QN VG Only varieties with fruit pubescence: absent. Fruit: conspicuousness of lenticels - - - - - - - - 48. QN VG Fruit: thickness of skin medium medium thick medium 5 5 7 5 49. QN VG Fruit: adherence of skin to flesh absent or very weak medium medium medium 1 5 5 5 World Journal of Advanced Research and Reviews, 2025, 27(01), 2051-2058 2056 50. QN VG Fruit: firmness of flesh firm medium medium medium 7 5 5 5 51. PQ VG Fruit: antocyanin coloration of flesh absent or very weak absent or very weak weak weak 1 1 2 2 52. QL VG Fruit: anthocyanin coloration Of flesh next to skin absent absent present absent 1 1 9 1 53. QN VG Fruit: intensity of anthocyanin coloration of flesh next to skin - - - weak - - 1 - 54. QL VG Fruit: anthocyanin coloration of flesh in central part of flesh absent absent present absent 1 1 9 1 55. QN VG Fruit: intensity of anthocyanin coloration of flesh in central part of flesh - - weak - - - 3 - 56. QL VG Fruit: anthocyanin coloration of flesh around stone absent absent present present 1 1 9 9 57. QN VG Fruit: intensity of anthocyanin coloration of flesh around stone - - weak weak - - 1 1 58. QN VG Fruit: flesh fibre without fibres with fibres without fibres without fibres 1 2 1 1 59. QN MG Fruit: sweetness weak high medium medium 3 7 5 5 60. QN MG Fruit: acidity weak medium medium medium 2 3 3 3 61. QN VG Stone: size in relation to fruit small medium medium medium 3 5 5 5 62. PQ VG Stone: shape (in lateral view) oblate obovate obovate obovate 1 4 4 4 63. QN VG Stone: anthocyanin coloration absent or very weak absent or very weak weak weak 1 1 3 3 64. QN VG Stone: intensity of brown colour light medium medium dark light 3 5 7 3 65. PQ VG Stone: relief of surface small cavities grooves small cavities grooves 1 5 1 5 World Journal of Advanced Research and Reviews, 2025, 27(01), 2051-2058 2057 66. QL VG Stone: adherence to flesh present present absent absent 9 9 1 1 67. QN VG Stone: degree of adherence to flesh weak weak - - 3 3 - - 68. QN MG Time of beginning of leaf bud burst medium medium medium medium 5 5 5 5 69. QN MG Time of beginning of flowering medium medium medium medium 5 5 5 3 70. QN MG Time of maturity medium early late late 5 3 7 7 In the table 1 are shown the results concerning the level of expression of characteristic on some peach varieties Alex, Alexa, Flacara and Triumf. For each character was done the note from 0 to 10. Concerning the characteristic on tree size and the tree vigor the varieties Alex, Alexia and Flăcara was the medium values. Concerning the Flowering shoot: presence of anthocyanin coloration all the vaieties tahes teh 9 note. The variety Flacara and Triumf are the notre 3 on flower type campanulate. Concerning the characters of Fruit: flesh fibre the most value variey is Alexia with note 2. Concerning the Fruit: anthocyanin coloration of flesh in central part of flesh the variety Flacara are the note 9 with coloration. 4. Conclusions The evaluation and characterization of the four peach genotypes according to their phenotypic expression allows the highlighting of the amplitude of genetic variability, thus paving the way for a future genetic improvement program. From a phenotypic point of view, the following were noted (Table 1): • Blooming is a genetically determined feature and correlated with the fruit maturing period; • Harvest maturity is a characteristic to be taken into account in any breeding program, with a particular interest in the two extremes, obtaining genotypes with a very early and very late maturity (the genotype may be used as a source of genes : for early - alexia variety, for late - flacăra and triumph varieties; • The size of the fruit is one of the highlights of the commercial aspect, especially when the fruit is used fresh, for the breeding program, especially with the large and very large fruit genotypes. • There is a wide variability of characters, which allows multiple choices of genitors as potential sources of genes to achieve the objectives set in the amelioration program. • Studies on the available biological material have highlighted the existence of basic genitors with mutually complementary characteristics. The concern to enrich the germplasm fund and to find new sources of genes more valuable than existing ones remains a permanent goal for breeders. Compliance with ethical standards Disclosure of conflict of interest No conflict of interest to be disclosed. References [1] Bellini, E., Scaramuzzi, F. 1976: Monografia delle principali cultivar di pesco. Vol. II., C.N.R., Firenze, IT, 564 pp [2] Brozik, S., Termesztett gyumolcsfajtaink 2. Csonthejastermesuek. Oszibarack (Fruit varieties 2., stone fruits peach)," Mezogazdasagi Kiado, Budapest, HU, 64 pp. World Journal of Advanced Research and Reviews, 2025, 27(01), 2051-2058 2058 [3] Ivascu, Antonia, 2003: Peach varieties catalog (catalogul soiurilor de pierSic), ed. Medro Ro, 110 p. Leroy, A., 18 [4] Morettini, A., et al., 1967: Monografia delle principali cultivar di pesco. Consiglio nazionale delle Ricerche. Centro miglioramento piante da frutto e da orto, Firenze, IT, 633 pp. [5] Okayama-ken, 1978: The report on the characterization and classification of peach varieties. Okayama-ken (Byconsignment of the MAFF), JP, 267 pp. [6] Timon, B., 1976: Oszibarack (peach). Mezogazdasagi Kiado, Budapest, HU, 424 pp. [7] Takashi Haji, Hideaki Yaegaki, Masami Yamaguchi Department of Breeding, National Institute of Fruit Science: Inheritance and expression of fruit texture melting, non-melting and stony hard in peach. Scientia Horticulture 105 (2005) 241-248 [8] cpvo.europa.eu/sites/default/files/documents/TP/adopted/CPVO-TP_PRUNUS_PERSICA_053_2_Rev.pdf