Performance of the pear (Pyrus communis) cultivar William s Bon Chretien grafted on seven rootstocks

Transcription

1 CSIRO PUBLISHING Australian Journal of Experimental Agriculture, 2006, 46, Performance of the pear (Pyrus communis) cultivar William s Bon Chretien grafted on seven rootstocks NAGREF, Pomology Institute, PO Box 122, Naoussa, Greece. thosotir@alfanet.gr Abstract. The performance of the pear (Pyrus communis L.) cv. William s Bon Chretien (William s BC) grafted on 7 rootstocks was evaluated over a period of 8 years. The scions of the cultivar William s BC were grafted on the following 7 rootstocks: (i) P. communis seedlings, (ii) quince BA 29, (iii) quince A, (iv) Pomology Institute (PI) 1, (v) PI 5, (vi) PI 27, and (vii) quince Komotinis (iv vii are Greek local quince seedlings). Compatibility of William s BC with P. communis, PI 1 and PI 27 was excellent and no tree losses occurred. The highest yield per tree was recorded when William s BC was grafted on PI 5 rootstock, although it was not significantly different from P. communis. The lowest yield was recorded when the cultivar was grafted on BA 29 rootstock. Production efficiency of William s BC was highest when grafted on PI 27, intermediate on quince A, PI 1 and PI 5 and lowest on P. communis. Iron concentration of leaves of scions grafted on P. communis, BA 29, quince A and quince Komotinis were significantly lower than those grafted on PI 5. From the results it is concluded that the rootstocks PI 1 and PI 27 are suitable for the cv. William s BC under Greek or other similar climatic conditions. Introduction European pear cultivars are propagated mainly through budding or grafting onto rootstocks because they are not homozygous, ruling out the propagation on their own roots. The rootstocks used are common pear (Pyrus communis L.) or quince (Cydonia oblonga Mill.). The former is compatible with all scion cultivars, the latter only with a part of the pearcultivar assortment (Lombard and Westwood 1987). Common pear rootstocks are considered more cold hardy and less susceptible to lime-induced chlorosis, whereas quince rootstocks are less vigorous, more precocious, better in fruit size, and less susceptible to pear decline. However, such generalisations are of limited value because within both species variations in the characteristics occur (Wertheim 2002). The choice of a rootstock suitable to a given set of conditions is crucial, yet obviously no single best rootstock is found that is suitable to all conditions where pears are grown. Pear rootstocks in Europe have been principally domestic or wild pear seedlings (Pyrus communis) for the colder regions, and quince has been used in several Mediterranean regions. Rootstock usage and practices vary with country and latitude (Lombard and Westwood 1987). Pear rootstocks are propagated by means of seeds, hardwood cuttings or in vitro culture (Bell and Reed 2002; Wertheim 2002). When propagated by seeds of various pear species, plants are not genetically uniform. In contrast, by using propagation by hardwood cuttings and in vitro culture plants are genetically uniform. In vitro propagation of pear rootstocks (mainly quince) is used extensively in Greece followed by propagation with hardwood cuttings. Rootstock affects tree size and vigor (Marangoni and Mazzanti 1999), tree nutrition (Fallahi and Larsen 1984), precocity, productivity and yield efficiency (Sugar et al. 1999), fruit size (Jacob 1998), fruit quality (Garcin et al. 1994), compatibility (Ermel et al. 1997), cold hardiness (Palonen and Buszard 1997) and pear decline and fire blight sensitivity (Le Lezec et al. 1997; Lemoine et al. 1998). William s BC pear cultivar is of high significance for many countries since it is 1 of the main cultivars used by the canning industry. However, in the first years of its cultivation in Greece it was grafted on BA 29 rootstock which was suitable for that cultivar in the climatic conditions of northern France, but its expansion failed because of its incompatibility with that rootstock under Greek conditions. At present, in order to avoid breakage at the grafting point, interstocks of the cultivars Beurre Hardy or Decana del Comizio between the scion and the quince A rootstock are often utilised. However, research for finding a suitable rootstock for this cultivar is still very important. The aim of the present research was to study the performance of the cultivar William s BC grafted on 7 rootstocks in terms of fruit yield, fruit weight, production efficiency, fruit quality parameters, trunk growth, breakage at the grafting point and leaf mineral status of the trees. Materials and methods Rootstocks The trees of the pear (Pyrus communis L.) cultivar William s BC were grafted on the following 7 rootstocks: (i) Pyrus communis seedlings, (ii) quince BA 29, (iii) quince A, (iv) quince selections at the Pomology Institute (PI) 1, (v) PI 5, (vi) PI 27, and (vii) quince Komotinis. PI 1, PI 5, PI 27 and Komotinis are Greek local quince seedlings genetically different. CSIRO /EA /06/050701

2 702 Australian Journal of Experimental Agriculture Table 1. Seasonal temperature and rainfall patterns of the area of the experimental orchard Values presented are means of 8 years (from the establishment of the orchard to the 8th year of the trees) Month Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Mean temperature ( C) Rainfall (mm) Site characteristics The experimental trees were trained as a palmette. The within rows spacing of trees was 2 m and the between row spacing was 3.5 m. Trees were irrigated by means of microsprinklers. Fertilisation per hectare during the 4th year of the trees consisted of 300 kg N, 100 kg P, 170 kg K and 20 kg Sequestrene 138 (FeEDDHA, 6% Fe) as was indicated by leaf and soil analyses. Afterwards, from the 5th to the 8th year of the trees, nutrient input per year was limited to 110 kg N, 30 kg P, and 80 kg K as was suggested by leaf analyses (Shear and Faust 1980) and since fruits and shoots removed by pruning were recycled within the orchard. The seasonal temperature and rainfall patterns of the area of the experimental orchard over a period of 8 years are presented in Table 1. Soil description and analyses The soil was silty clay loam in texture and had an average ph of 7.1, and electrical conductivity of ms/cm. The free CaCO 3 and organic matter contents were 0.91 and 0.95%, respectively. The soil samples were air dried, crushed to pass a 2-mm screen and analysed for ph in a 1:1 soil to water ratio, electrical conductivity in a 1:5 soil to water extract, texture (hydrometer method), CaCO 3 with a volumetric calcimeter and organic matter content after wet oxidation (Page et al. 1982). Soil chemical analysis (mg nutrient/kg of air-dried soil) of the experimental orchard was P, 11; K, 113; Ca, 381; Mg, 126; Mn, 21; Zn, 0.92; Fe, 0.93; and 0.22 mg B/L of saturation extract of the soil. Phosphorus was determined by the Olsen procedure, K after extraction with ammonium acetate, Ca and Mg volumetrically with 0.1 mol/l EDTA, while Fe, Mn and Zn with atomic absorption spectrometry after extraction with DTPA (Page et al. 1982). Boron was determined by the azomethine-h method in the saturation extract of the soils (Wolf 1971). Plant chemical analysis Leaf samples were collected at 15 July (mid-summer) from the 4th to the 8th year ( ) after the establishment of the orchard and consisted of 50 leaves per sample. Leaves were collected from the middle of moderately vigorous shoots from each tree around the periphery, at shoulder height. Leaf samples were initially washed once with tap water and twice with distilled water. Then, they were dried in a forced draft oven at 68 C for 72 h and ground in a mill to pass a 30-mm mesh screen. Nitrogen was determined by the Kjeldahl procedure, B by the azomethine-h method (Wolf 1971), P by the ammonium phosphovanadomolybdate method (Jackson 1970) and K, Ca, Mg, Fe, Mn and Zn by atomic absorption spectrophotometry. Trunk circumference was measured at a point 30 cm above soil level every year, but the data presented are trunk circumference values at the end of the 8th year (2003). Yields were yearly recorded and data presented are the means of 4 years, from the 4th to the 8th year after the establishment of the orchard ( ). Mean fruit weight was estimated as the ratio of total yield per scion/rootstock combination to total number of fruits, from 2000 to Fruit samples (10 fruits per tree) were also collected at fruit ripening over a period of 4 years ( ). Flesh firmness was measured by an Effegi penetrometer (11 mm tip). Soluble solids analysis was also performed by an Atago PR-1 electronic refractometer. Percentage of grafts that showed breakage at the grafting point was calculated by the end of the 8th year. Production efficiency was determined as the ratio of yield (kg/tree at the 8th year) to trunk cross section (cm 2 ) at the 8th year. To establish the precocity induced by the different rootstocks, flower density was evaluated during bloom at the 8th year of the trees by counting corymb number on 2 branches of each tree. This parameter is expressed per linear meter of branch. Statistical analysis The experimental design was a randomised block with 4 replications of 7 treatments (rootstocks) and 4 trees per plot. Differences between means were evaluated by Duncan s multiple range test at P = Results and discussion Trunk circumference was highest when William s BC was grafted on P. communis rootstock and followed by PI 5, while the lowest was recorded on quince A and PI 27 (Table 2). Trunk circumference in comparison to P. communis diminished in the following order PI 5, quince Komotinis, PI 1, BA 29, quince A and PI 27. Pear trees can be kept small by using dwarfing rootstocks. However, vigour is also determined by soil, climate, and scion cultivar. Dwarfing rootstocks do exist within P. communis such as Pyrodwarf and Horner (Mielke and Smith 2002). Loreti et al. (2002) reported that cv. Conference grafted on BA 29 and Sydo quince rootstocks had higher trunk circumference in comparison to EM QA, EM QC, and Adams quince rootstocks. Trunk circumference was highest when Comice pear cultivar was grafted on BA 29 rootstock in comparison to QC quince rootstock (Palmer 2002). Castro and Rodriguez (2002) reported that trunk circumference of the cvv. Conference and Abbe Fetel grafted on BA 29, Provence, and MA quince rootstocks were not significantly different. Table 2. Trunk circumference, and percentage of grafts that showed breakage at the grafting point of the William s BC pear cultivar grafted on 7 rootstocks Measurements were performed at the 8th year of the trees. Means within columns followed by the same letter in the same column are not significantly different (Duncan s multiple range test P = 0.05) Rootstock Trunk Percentage of grafts circumference that showed breakage (cm) at the grafting point (%) P. communis 34.3a 0.0 BA d 29.2 Quince A 21.3e 17.3 PI c 0.0 PI b 17.1 PI e 0.0 Quince Komotinis 23.9c 15.4

3 Performance of pear grafted on different rootstocks Australian Journal of Experimental Agriculture 703 Table 3. Mean yield, mean fruit weight, soluble solids content and fruit firmness of the William s BC pear cultivar grafted on 7rootstocks over a period of 4 years (from the 4th to the 8th year after establishment of the orchard) Flowering density and production efficiency were estimated at the 8th year of the trees. Means within columns followed by the same letter in the same column are not significantly different (Duncan s multiple range test P = 0.05) Rootstock Mean yield Mean fruit Flowering density Production efficiency Soluble solids Fruit firmness (kg/ tree) weight (g) (number of [kg/tree.trunk (% Brix) (kg) corymbs/metre) cross section (cm 2 )] P. communis 24.2ab 228ab 18.7d 0.71e 12.7c 8.2a BA e 226ab 33.2a 0.83d 14.9a 7.4b Quince A 17.2d 200c 28.3b 1.20b 14.8a 8.0ab PI cd 220b 27.2bc 1.22b 13.8b 7.5b PI a 232a 26.8bc 1.12bc 13.4b 7.7b PI cd 217b 25.9c 1.35a 14.4ab 7.8b Quince Komotinis 19.4c 206c 26.8bc 1.10c 13.7b 7.6b Compatibility of William s BC with P. communis, PI 1 and PI 27 was excellent and no tree losses occurred. However, percentage of grafts that broke at the grafting point was highest for BA 29, followed by quince A, PI 5 and quince Komotinis (Table 2). The graft failure on the previous rootstocks could not be attributed to genetic variation in the rootstock population since they were propagated by hardwood cuttings. It is genotype dependent because not all pear scion cultivars are compatible with quince rootstocks (Lombard and Westwood 1987). With the exception of cultivars that are clearly compatible or incompatible, a number of cultivars are rated as having variable compatibility (Carrera 1994). Castro and Rodriguez (2002) reported that the cvv. Conference and Abbe Fetel should not be grafted directly on quince selections BA 29, Provence, and MA under the ecological conditions of Rio Negro Valley of Argentina because incompatibility problems were observed. Rootstocks had a significant effect on yield, causing major differences with the scion cultivar William s BC (Table 3). The highest yield per tree was recorded from trees on PI 5 rootstock, although it was not significantly different from P. communis. The lowest yield was recorded when the cultivar was grafted on BA 29 rootstock. In a previous study, Castro and Rodriguez (2002) also reported that yield of the cvv. Conference and Abbe Fetel grafted on pear seedling was higher than the quince selections Provence, BA 29, and MA. Mean yield per tree of the cv. Comice grafted on BA 29 rootstock was significantly higher in comparison to QC (Palmer 2002). Yield (kg/tree) of the cv. Cascade grafted on the quince rootstock CTS212 was higher in comparison to BA 29, Sydo and Adams (Musacchi et al. 2002). Production efficiency of William s BC was highest when grafted on PI 27, intermediate on quince A, PI 1 and PI 5, and lowest on P. communis (Table 3). Musacchi et al. (2002) reported that production efficiency of the cv. Cascade grafted on CTS212 quince rootstock was significantly higher in comparison to BA 29, Sydo and Adams. Rootstock had a significant effect on tree size, as reflected by trunk circumference measurements. Within a few years of planting trees on vigorous rootstocks may yield more than those on dwarfing ones because of their greater size. However, this superiority may not hold for yield efficiency (production per unit of growth). Yield efficiency does not seem to be clearly related to rootstock vigour (Sugar et al. 1999). Wertheim (2002) reported that MC and BA 29 rootstocks showed higher yield efficiency than OH (Old Home) 11, OH 20, OH 33 and OHxF (Old Home Farmingdale) 333 rootstocks. Table 4. Mineral concentration of leaves of the William s BC pear cultivar grafted on 7 rootstocks over a period of 4 years (from the 4th to the 8th year from the establishment of the orchard) Means within columns followed by the same letter in the same column are not significantly different (Duncan s multiple range test P = 0.05) Rootstock N P K Ca Mg Fe Mn Zn B (% DM) (% DM) (% DM) (% DM) (% DM) (µg/g DM) (µg/kg DM) (µg/kg DM) (µg/kg DM) P. communis 2.54a 0.24a 1.84a 2.23a 0.38a 195b 46ab 20ab 38a BA a 0.21a 1.52c 1.63d 0.32b 178d 42c 17b 32bc Quince A 2.48a 0.22a 1.69bc 1.80c 0.35b 189c 45b 18b 35ab PI a 0.24a 1.79ab 2.11b 0.37ab 205ab 47ab 21a 36ab PI a 0.22a 1.76ab 2.07b 0.35b 210a 48a 20ab 36ab PI a 0.24a 1.80ab 2.17ab 0.36ab 202ab 43bc 19ab 34b Quince Komotinis 2.41a 0.22a 1.71ab 1.79c 0.34b 188c 42c 18b 32bc

4 704 Australian Journal of Experimental Agriculture Rootstock significantly affected mean fruit weight (Table 3). The highest mean fruit weight was measured when William s BC was grafted on PI 5 but it was not significantly different from P. communis and BA 29. The lowest mean fruit weight recorded when William s BC was grafted on quince A and quince Komotinis rootstocks. Rootstock may have direct or indirect effect on pear fruit size and weight. A direct effect is shown by some Pyrus rootstocks (OH F 33, OH F 333), which induced smaller fruits than the quince rootstocks (BA 29, MC) with which they were compared in spite of lower fruit densities. Wertheim (2002) reported that quince rootstocks induce larger fruit than Pyrus rootstocks, but other data contradict this (Bassi et al. 1994; Sugar et al. 1999). Indirect rootstock effects on fruit size, related to fruit density (tree cropping efficiencies), seem to occur within quince rootstocks. The reported good fruit size of Conference on QR rootstock compared to MC may be related to its lower efficiency (Wertheim 2002). Nevertheless, with the cv. Clara Frijs, quince Adams gave larger fruit than MA independent of fruit density. Hence, within quince direct effects on fruit size may occur as well (Wertheim 2002). This is observed in our study as well for PI 5, PI 1, PI 27, quince Komotinis, and quince A rootstocks that induced different fruit weight of scions although flower density was not significantly different (Table 3). Soluble solids content of fruits from scions grafted on BA 29, and quince A were significantly higher in comparison to PI 1, PI 5, quince Komotinis and P. communis (Table 3). Furthermore, there were no significant differences in fruit firmness among the rootstocks (Table 3). In general, fruit quality parameters and storage behaviour seem to be little affected by rootstock (Wertheim 2002). Husain et al. (2003) studied the performance of the cv. Williams grafted on OHF 333, BA 29, BA 29 with interstock B. Hardy, Kirschensaller and the own rooted Williams. They concluded that there were no significant differences in fruit firmness and soluble solid contents among the rootstocks. With regard to leaf nutrient status, the most significant differences among rootstocks were observed for K, Ca and Fe (Table 4). Potassium concentration of leaves of the cultivar William s BC grafted on BA 29 and quince A were significantly lower in comparison with P. communis. Lombard and Westwood (1976) concluded that various pear cultivars had high levels of K on P. calleryana and P. betulaefolia rootstocks. Calcium concentrations of leaves were higher when scions were grafted on P. communis and followed by PI 27 and PI 1 rootstocks. Cork spot of Anjou pear (similar to bitter pit of apple) is reduced with rootstocks such as Old Home, which result in high levels of Ca in the scion cultivar (Lombard and Westwood 1987). Iron concentration of leaves of scions grafted on P. communis, BA 29, quince A and quince Komotinis were significantly lower in comparison to PI 5. Therefore, PI 5 rootstock is more suitable than the others for use on soils with high Ca content. Chaplin and Westwood (1980) reported that under western Oregon conditions the cv. Williams grafted on Cydonia oblonga has low uptake of Fe in comparison to P. amygdaliformis, P. syriaca and P. eleagrifolia. Fallahi and Larsen (1984) reported that leaves of the pear cultivar Bartlett were high in Fe on Bartlett seedlings, in Zn on P. ussuriensis and in B on seedlings of P. calleryana. Nitrogen, P, Mn, and B concentrations of leaves of scions grafted on all rootstocks were within ranges usually associated with high producing trees whereas Zn concentrations were lower (Shear and Faust 1980). As pear rootstocks are known to affect the concentration of mineral elements in scion leaves, it might be possible to take advantage of these effects in situations where specific elements are a problem (high or low according to the situation). References Bassi D, Tagliavini M, Marangoni B (1994) Selection of clonal rootstocks of Pyrus communis (L.). Acta Horticulturae 367, Bell RL, Reed BM (2002) In vitro tissue culture of pear: advances in techniques for micropropagation and germplasm preservation. Acta Horticulturae 596, Carrera M (1994) La dissafinita d innesto delle cultivar di pero su cotogno. Rivista Frutticolturae. 56, Castro HR, Rodriguez RO (2002) The behaviour of quince selections as pear rootstocks for Abbe Fetel and Conference pear cultivars in the Rio Negro Valley, Argentina. Acta Horticulturae 596, Chaplin MH, Westwood MN (1980) Effects of Pyrus species and related genera rootstocks on mineral uptake in Bartlett pear. Journal of Plant Nutrition 2, Ermel FF, Poessel JL, Faurobert M, Catesson AM (1997) Early scion/stock junction in compatible and incompatible pear/pear and pear/quince grafts: a histocytological study. Annals of Botany 79, doi: /anbo Fallahi E, Larsen F (1984) Rootstock influence on leaf and fruit mineral status of Bartlett and D Anjou pear. Scientia Horticulturae 23, doi: / (84) Garcin A, Edin M, Mathieu V, Hilaire C (1994) Poirier: maturité et qualité de William s en fonction du porte-greffe. Infos-Ctifl 103, Husain S, Urbina V, Dalmases J, Pascual M, Dalmau R (2003) Performance of Williams pear on five rootstocks. Journal of Horticultural Science and Biotechnology 78, Jackson ML (Ed.) (1970) Soil chemical analysis. (Prentice Hall Inc.: Madison) Jacob H (1998) Pyrodwarf: a new clonal rootstock for high density pear orchards. Acta Horticulturae 475, Le Lezec M, Lecomte P, Laurens F, Michelesi JC (1997) Sensibilité varietable au feu bactérien (1 re partie). L Arboriculture Fruiterie 44, Lemoine J, Simon M, Costard F, Bossu V, Pradier B (1998) Le dépérissement du Poirier ou pear decline. L Arboriculture Fruiterie 45, Lombard PB, Westwood MN (1976) Performance of six pear cultivars on clonal Old Home, double rooted and seedling rootstocks. Journal of the American Society for Horticultural Science 101, Lombard PB, Westwood MN (1987) Pear rootstocks. In Rootstocks for fruit crops. (Eds RC Rom, RF Carlson) pp (John Wiley and Sons: New York)

5 Performance of pear grafted on different rootstocks Australian Journal of Experimental Agriculture 705 Loreti F, Massai R, Fei C, Cinelli F (2002) Performance of Conference cultivar on several quince and pear rootstocks: preliminary results. Acta Horticulturae 596, Marangoni B, Mazzanti F (1999) I portinesti del pero. L Informatore Agrario 6, Mielke EA, Smith L (2002) Evaluation of the Horner rootstocks. Acta Horticulturae 596, Musacchi S, Ancarani V, Grandi M, Sansavini S (2002) Comparative field performance of cvs. Sensation Red Bartlett and Cascade grafted to six quince and pear clonal seedling rootstocks. Acta Horticulturae 596, Page AL, Miller RH, Keeney DR (1982) Chemical and microbiological properties. In Methods of soil analysis. (Eds AL Page, RH Miller, DR Keeney) pp (ASA-SSSA: Madison) Palmer JW (2002) Effect of spacing and rootstock on the performance of Comice pear in New Zealand. Acta Horticulturae 596, Palonen P, Buszard D (1997) Current state of cold hardiness research on fruit crops. Canadian Journal of Plant Science 77, Shear CB, Faust M (1980) Nutritional ranges in deciduous tree fruits and nuts. Horticultural Reviews 2, Sugar D, Powers KA, Basile S (1999) Effect of rootstock on fruit characteristics and tree productivity in seven red-fruited pear cultivars. Fruit Varieties Journal 53, Wertheim S (2002) Rootstocks for European pear: a review. Acta Horticulturae 596, Wolf B (1971) The determination of boron in soil extracts, plant materials, composts, manures, water and nutrient solutions. Communications in Soil Science and Plant Analysis 2, Received 13 July 2004, accepted 14 January