THE BEHAVIOUR OF CERTAIN PEACH TREE CULTIVARS TOWARDS THE ATTACK OF THE MAIN PATHOGEN AGENTS

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1 Scientific Papers. Series B, Horticulture. Vol. LVIII, 2014 Print ISSN , CD-ROM ISSN , Online ISSN , ISSN-L THE BEHAVIOUR OF CERTAIN PEACH TREE CULTIVARS TOWARDS THE ATTACK OF THE MAIN PATHOGEN AGENTS Cristina MOALE 1, Corina GAV 1, Leinar SEPTAR 1, Ligia ION 2 1 Research Station for Fruit Growing Constanta, 1 Pepinierei, , Commune Valu lui Traian, District Constanta, Romania, Phone /Fax , moalecristina@yahoo.com 2 University of Agronomic Sciences and Veterinary Medicine of Bucharest, 59 M r ti, District 1, Bucharest, Romania, Phone: /232, Fax: , ionnagyligia@yahoo.fr Abstract Corresponding author moalecristina@yahoo.com The purpose of this paper is to highlight cultivars which are most resistant to disease and pests and which have adapted most efficiently to pedo-climatic conditions of Dobrogea. The research took place during period at RSFG Constanta in a peach tree culture planted in 1991 and it involved following cultivars: 'Springold', 'Springcrest', 'Cardinal', 'Collins', 'Redhaven', 'Jerseyland' and 'Southland'. Observations were recorded concerning attack of several fungi (Taphrina deformans, Cytospora cincta, Monilinia laxa and Monilinia fructigena) following application of phyto-sanitary treatments with insecticides and fungicides administered at right moment and in optimum quantities. Among studied pathogens, blistering of leaves caused by Taphrina deformans Berk et Tull. fungus is by far most damaging foliar pathogen agent. Its attack has serious consequences both upon fruit production as well as upon physiological balance of trees, resulting in ir degradation. Within pedo-climatic conditions of south-eastern part of country, this disease is quite frequent in cultures which causes severe damage. The majority of studied cultivars manifested and elevated resistance towards attack of Taphrina deformans pathogen. In, 'Springold' and 'Springcrest' cultivars were sensitive towards this pathogen agent. As far as latter is concerned, we must mention fact that sensitivity of cultivar is also influenced by environmental conditions specific to each studied year. The most resistant cultivar (basically, without attack) towards Cytosphora Cincta is 'Redhaven', while most sensitive was 'Collins'. As far as Monilinia laxa and Monilinia fructigena fungi are concerned, all studied cultivars proved to be tolerant. Following this study, most valuable genotypes can be extended in demonstrative allotments and commercial plantations. Key words: resistance, blistering, natural infection, Prunus persica INTRODUCTION In our country, Dobrogea is region that offers most favourable conditions for peach tree culture. Unfortunately, however, this area is also favourable for development of certain extremely harmful pathogen agents, such as: Taphrina deformans, Cytospora cincta, Monilinia laxa and Monilinia fructigena. The diseases caused by attack of pathogens are frequent when spring is cold and humid and cloudy for long periods of time. Under se conditions attack is strong and quality of production diminishes considerably. The peach tree is third most import fruitgrowing species in our country, after apple tree and plum tree and is cultivated in warmer areas, with an average annual temperature of C. The soil needs to be deep, aerated, with a ph varying between and 7.5; also, content of active limestone must not surpass 7% when using franc parent stock and 15% when parent stock is an almond tree (St nic and Brani te, ). The peach tree is widely spread, in Europe (43% of annual production, 18,000,853 t in 2008), Asia (23%), Central and North America (17%), South America, Africa, Oceania. 4,203,800 t were produced in Europe in 2008, most productive country being Italy (1,720,000 t), followed by Spain (1,149,000 t), Greece (700,000 t), France (401,000 t), etc. Romania produced 16,400 t in 2008 (St nic and Brani te, ). Both in our country as well as worldwide aim is to obtain fruits of a superior quality, with an increased and constant productivity of trees which should be resistant and/or tolerant to main diseases specific to species. The importance of knowing pathogen agents and pests which could attack peach tree is correlated

2 with practical necessities which occur in orchard and storage period, taking into account fact that quality standards of material for cultivation whose purpose is creation of new plantations, as well as quality standards of fruits can be achieved only if pathogens and pests are known so that ir attacks can be controlled. Trandafirescu (1998, 2007) has studied resistance to Taphrina deformans within peach tree and nectarine tree species, detailing research for each cultivar from national peach tree collection planted in The purpose is to highlight cultivars which are most resistant to diseases and pests in order to be extended in demonstrative allotments and commercial plantations, thus occupying a good place in structure of peach tree assortment from South-Eastern region of Romania. MATERIAL AND METHOD The research took place in period at R.S.F.G. Constan a, in Valu lui Traian, Constan a district, in a peach tree plantation planted in 1991, planting distance is 4/4m (625 trees/ha) and shape of trees is a free flat palmette. The studied cultivars have different ripening periods and are following: 'Springold', 'Springcrest', 'Cardinal', 'Collins', 'Redhaven', 'Jerseyland' and 'Southland'. Given fact that region is semi-arid, peach tree culture developed under an irrigated regime. The soil is a calcareous chernozem (CZka), with a claylike texture, a low alkaline ph (8.2) in its entire profile. The behaviour of peach tree cultivars towards attack of pathogens (Taphrina deformans, Cytospora cincta, Monilinia laxa and Monilinia fructigena) was observed under conditions of natural infection. From a technological point of view, 6-8 insecticide and pesticide treatments were applied against main disease and pests. The system concerning maintenance of soil was black ground between rows and herbicided on rows of trees (a strip of 50 cm). Observations were carried out concerning behaviour of certain peach tree cultivars towards attack of main pathogen agents, as well as observations regarding 60 phenology of studied cultivars ( swelling of flowering buds period and ripening time). Observations were also carried out concerning evolution of disease on leaves, fruit and sprouts following applying of phyto-sanitary treatments with insecticides and fungicides, treatments administered at optimal moment and dosage. The research was carried out under conditions of natural infection, according to test created by Crossa (1968). The evaluation technique consisted in assessing frequency of attacked organs and intensity with which symptoms manifested mselves, se being aspects according to which behaviour was assessed. The observations were performed by ranking intensity of attack on a scale of 0-4, as follows: W.A.= cultivars without attack (F%=0 and I=0) T=tolerant cultivars (F%=0.1-5% and I=0 + +) We.A.=weakly attacked cultivars (F%=5.1% - 10% and I=+) M.A.=moderately resistant cultivars (F%=10.1%-25% and I=+) S=sensitive cultivars (F%= % and I=+ 2 4) V.S.=very sensitive cultivars (F%=50.1%- 100%, I=+ 4 4) In order to determine development of main vegetative stages under conditions of R.S.F.G. Constanta, phonological observations were carried out concerning trees both in resting period, as well as during vegetative phase. Fructification phenophases As far as genesis of flowers is concerned, start of vegetation in spring represents continuation of process of flower creation which has been interrupted by biological resting period. The swelling of flowering buds; The beginning of blossoming. Similar to or vegetative stages, blossoming of trees is influenced by evolution of climatic conditions. The beginning of blossoming in period was recorded for all studied cultivars. Intensity The intensity of blossoming is appreciated on a scale of 0 to 5, specific moment of

3 appreciation being mass blossoming stage. The grade 0 is considered when cultivar has no blossoms whatsoever, while grade 5 is when cultivar displays a large amount of blossoms. The ending of blossoming; The blossoming can last a longer or shorter period of time depending on maximum temperatures during day and intensity of wind, correlated with degree of differentiation between trees (meaning quantity of blossoms per tree). The hardening of core; The hardening of core is determined by piercing fruit with a needle at regular intervals, usually of two days. When needle has difficulty piercing fruit it is considered that hardening of core has begun. The operation was performed in a progressive manner, according to calendar, in same day for all studied cultivars. The ripening of fruits; The ripening of fruits is highly influenced by a series of climatic and agro-technical factors, such as temperature, drought, quantity of fruit per tree, shape of crown, density of trees, etc. Taking calendar into account, each ripening period has large variation limits from one year to anor, depending on how climatic factors influence vegetation to be early, late or extra-late. RESULTS In period 2008-, phenophase of flowering buds swelling at peach trees (Table 1) underwent between following limits: Between and at 'Springold' Between and at 'Springcrest' Between and at 'Collins' Between and at 'Cardinal' Between and at 'Redhaven' Between and at 'Southland' Between and at 'Jerseyland' Basically, swelling of flowering buds occurred between and (one month). The beginning of blossoming Similar to or vegetative stages, blossoming of trees is influenced by evolution of climatic conditions. For all studied cultivars beginning of blossoming in period was recorded, differences between cultivars being very small (a few days), meaning that mutual pollination was ensured. Thus, limits for this stage were and The duration of blossoming depends on maximum temperatures during day and intensity of wind, correlated with degree of differentiation between trees (meaning quantity of blossoms per tree). The scaling was carried out when petals of last blossoms fell from trees. The duration of blossoming (average for four studied years, 2008-) expressed in number of days (Table 1) varied between 8 days ('Springold', 'Redhaven' and 'Southland' cultivars) and 22 days ('Springcrest', 'Collins' and 'Southland' cultivars in ). The intensity of blossoming In a weak intensity was recorded by 'Springold' and 'Springcrest' cultivars (2 and 3, respectively, upon blossoming). The 'Collins', 'Cardinal', 'Redhaven', 'Southland' and 'Jerseyland' cultivars displayed a significant intensity upon blossoming, of 4 and 5. The hardening of core This phenophase occurred in first ten days of June ( ). The harvesting maturity Its variation limits were June 21 st ('Springold') and August 10 th ('Southland'), this phenophase being genetically influenced. At Valu lui Traian pathogens of economic importance for this specie under conditions of studied period were following mycoses: Taphrina deformans Berk et Tull (blistering of leaves), Cytospora cincta Sacc (perennial cancer of sprouts), Monilinia laxa and Monilinia fructigena Aderh Ruhl Honey (rotting and mummification of fruit). 61

4 Table 1. The development of main fructification phenophases at peach tree in period No. CULTIVAR Year Swelling of flowering buds 1 SPRINGOLD 2 SPRINGCREST 3 COLLINS 4 CARDINAL 5 REDHAVEN 6 SOUTHLAND 7 JERSEYLAND Blossoming Intensity Hardening Beginning Ending Duration of core (days) Harvesting maturity Limits Limits Limits Limits Limits Limits Limits The resistance to diseases is one of most important problems of peach tree culture. Research have shown that, 20 years after planting, certain cultivars display a resistance towards attack of pathogen agents (Table 2). The analysis of data in table reveals fact that most of studied cultivars manifested an increased resistance towards attack of harmful pathogen Taphrina deformans, exception being 'Springold' and 'Springcrest' cultivars in years and (Figure 1), years in which y proved to be sensitive. In case of this pathogen we must mention fact that sensitivity of cultivar is 62

5 also influenced by environment tal conditions of each studied year. Among pathogens which constituted object of this paper, blistering of leaves caused by Taphrina deformans Berk ett Tull. fungus is undoubtedly most harmful foliar pathogen agent. Its attack has serious consequences both upon fruit production as well as upon physiological balance of trees, causing ir debilitation. The perennial cancer off peach tree caused by Cytospora cincta Sacc fungus is, toger with blistering caused by Taphrina deformans, most importantt pathogen which diminishes fruit production. Figure 1. The 'Springold' cultivar attacked by Taphrina deformans in May According to intensity (I) off attack studies cultivars were classified as follows (Table 2): Taphrina deformans - 6 resistance classes - Cultivars without attack (W.A.) two cultivars, intensity (I) of attack being zero: 'Redhaven' and 'Cardinal' (in studied years 2008,, ). - Tolerant cultivars (T) 'Collins', 'Jerseyland', 'Southland'; - Weakly attacked (We.A) no cultivars; - Sensitivee (S): 'Springold' and 'Springcrest'; None of studied cultivars entered moderately attacked and very sensitive classes. As far as attack of Cytospora cincta Sacc is concerned, observations revealed fact that sensitivity and resistance of cultivars towards it depend exclusivelyy on soil. The studied cultivars were classifiedd as follows: - Cultivars without attack (W.A.) only 'Redhaven'; - Tolerant cultivars (T 'Cardinal' (2008,, ) and 'Springold'; - Weakly attacked (We.A) 'Southland' (,, ), 'Springcrest' t' (2008,, ) and 'Jerseyland'; - Sensitive (S) 'Collins'.. None of studied cultivars entered moderately attacked and very sensitive classes. As far as attack of Monilinia laxa and Monilinia fructigena Aderh et Ruhl Honey fungi is concerned, all studied cultivars proved to be tolerant (T), both frequency (F%) as well as intensity off attack (I) being graded with zero. The introduction within cultures of peach treee cultivars with an increased resistance towards attack of most harmful pathogen agents has numerouss economic advantages, such as, among whichh diminishing of production losses and e reduction of expenses regardingg pesticides andd fuels. These are correlated with protection of environment reduction of battering of soil due to fact thatt tractor rarely crosses orchard, reconstructionn of soil s structure, reduction of pollution of both environment and fruit, as well as protection of consumers health. 63

6 Table 2. The behaviour of peach tree cultivars towards attack of main pathogen agents in period No. Cultivar Year Taphrina deformans Cytospora cincta Monilinia Resistance class Resistance class laxa fr. Intensity of attack (grades*) Intensity of attack (grades*) Intensity of attack (grades*) WA T We A S MA VS W A T We A S MA VS T T Cultivars planted in SPRINGOLD SPRINGCREST CARDINAL COLLINS REDHAVEN JERSEYLAND SOUTHLAND 2008 * Grade Intensity of attack CONCLUSIONS Most of studied cultivars manifested an increased resistance towards attack of harmful pathogen agent Taphrina deformans, being eir without attack (W.A.) or tolerant (T). The 'Springold' and 'Springcrest' cultivars proved to be more sensitive. As far as attack of Cytosphora cincta fungus is concerned, sensitivity and resistance depend exclusively on soil. The 'Collins' cultivar proved to be sensitive, whereas 'Redhaven' cultivar proved to be resistant. As far as attack of Monilinia laxa and Monilinia fructigena fungi is concerned, all studied cultivars proved to be tolerant (T). The cultivars from Valu lui Traian which manifested an increased resistance towards attack of pathogens of economic importance will be recommended for usage in works of improvement, as well as for extension in production. These cultivars which are resistant to Taphrina deformans will simplify peach tree s crop technology for small areas and will ensure a biological production towards which all cultivators aim. 64

7 REFERENCES Crossa Raynaud P.H., Evaluating Resistance to Monilinia laxa (Aderh&Ruhl) Honey of varieties and Hybrids of Apricots and Almonds using Mean Growth Rate of Cankers on Young Branches as Criterion of Susceptibility. J. Amer. Soc. Hort. Sci. 94, p Genard M, Reich M, Lobit and Besset J, Corelatin between sugar and acid contend and peach growth. J.Hort. Sci. Biot 74(6), p St nic F., Braniste N.,. Ghid pentru pomicultori, Editura Ceres, Bucuresti, ISBN , p Suta V., Trandafirescu M., Planul tratamentelor fitosanitare la piersic si nectarine in plantatiile intensive. Tehnologia combaterii bolilor si daunatorilor, arbustilor fructiferi si a capsunului, p Trandafirescu M., Sensibilitatea unor soiuri si hibrizi de piersic fata de atacul ciupercii Cytospora cincta Sacc. Lucrari stiintifice, ICPP, vol.xv. Trandafirescu M, The sensitivity of some peach tree varieties and hybrids to attack of fungus Taphrina deformans (Berk.)Tul., Acta Horticulturae et regiotecture, Nitra September, p Trandafirescu M., Topor E. and Teodorescu G, Rezistance to Taphrina deformans (Berk.) Tul. in Peaches and Nectarines in Souastern Romania, Acta Horticulturae 760, July 2007, Seoul, Korea, p