Flowering and Fruiting of "Burlat" Sweet Cherry on Size-Controlling Rootstock
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HORTSCIENCE 29(6):611–612. 1994. chart uses eight color chips to assess fruit color: 1 = light red to 8 = very dark, mahogany red. At the end of the growing season, all Flowering and Fruiting of ‘Burlat’ current-season’s shoot growth, >2.5 cm, was measured on each branch unit. Sweet Cherry on Size-controlling We analyzed the data as a factorial, ar- ranged in a completely randomized design, Rootstock with rootstock and age of branch portions as main effects. The least significant difference Frank Kappel was used for mean separation of main effects. Agriculture Canada, Research Station, Summerland, B.C. VOH IZO, Canada Results Jean Lichou The sample branches had similar BCSA, Ctifl, Centre de Balandran, BP 32, 30127 Bellegarde, France with the mean ranging from 3 to 3.7 cm2 for the Additional index words. Prunus avium, Prunus cerasus, Prunus mahaleb, fruit size, fruit branch units of the trees on the three root- stock. The mean for the branch units’ total numbers, dwarfing, Edabriz, Maxma 14, F12/1 shoot length ranged from 339 to 392 cm. Abstract. The effect of rootstock on the flowering and fruiting response of sweet cherries ‘Burlat’ branches on Edabriz had more (Prunus avium L.) was investigated using 4-year-old branch units. The cherry rootstock flowers than ‘Burlat’ branches on F1 2/1 or Edabriz (Prunus cerasus L.) affected the flowering and fruiting response of ‘Burlat’ sweet Maxma 14 when expressed as either total cherry compared to Maxma 14 and F12/1. Branches of trees on Edabriz had more flowers, number of flowers or number standardized by more flowers per spur, more spurs, more fruit, higher yields, smaller fruit, and a reduced shoot length (Table 1). There were more than fruit set compared to the standard rootstock, F12/1. One-year-old branch sections had double the number of flowers for ‘Burlat’ on more flowers and fruit, higher fruit weight, and heavier fruit size compared to older Edabriz than for trees on F1 2/1 (either total branch portions. number or number per unit shoot length). ‘Burlat’ branches on Maxma 14 had »30% Size-controlling or dwarfing rootstock for Balandran, near Nîmes in southern France. more flowers total than branches of trees on sweet cherries that are precocious and produc- Rootstock were Edabriz, Maxma 14, and F1 2/1. Flowers per shoot length did not differ tive could allow developing more productive F12/1 (control). The trees were spaced 6 m between Maxma 14 and F12/1. orchard systems. These orchards would be between rows and 4 m within rows. Trees were Across rootstock, the l-year-old wood more labor efficient because most of the prun- allowed to develop naturally with little train- had more flowers (expressed as total number ing and harvesting could be done from the ing or pruning over the years. Some smaller or per unit shoot length) than the older portions ground. Edabriz and Maxma 14 are among the lateral branches were removed in 1991, and in of the branches. The 3- and 4-year-old por- rootstock that have been selected for dwarf- Spring 1992, one or two major branches were tions had about half the number of total flow- ing potential. Edabriz is from Prunus cerasus, removed from each tree. ers of the 1-year-old wood. which is size-controlling and precocious in its In Spring 1992, three 4-year-old branch There was, however, a significant interac- effect on sweet cherry scions (Edin et al, units of similar vigor were chosen in each tree; tion between rootstock and age of wood, with 1989). Maxma 14’ is believed to be derived these branches had not been pruned in 1991. thedifferent-aged portions of ‘Burlat’ branches from across between mazzard (Prunus avium) There were four trees of each rootstock. The on Edabriz having more flowers than the other and Prunus mahaleb L. (Perry, 1987). Trials in branch cross-sectional area (BCSA) of each two rootstock. The branches of ‘Burlat’ on France demonstrated that Maxma 14 was branch unit was measured at the base of the Edabriz had at least one flower per cm on all semi-dwarfing and improved the precocity of 4-year-old portion (just distal to the ring of bud four ages of wood, whereas for the other two the scion cultivar (Edin et al., 1989). German scale scars). The total length of each branch rootstock, only the 1-year-old wood had at researchers showed that rootstock can affect portion of similar age was measured. During least one flower per cm. the fruiting characteristics of cherry trees. the bloom period, the number of flowers and Branches of trees on Maxma 14 had sig- Clonally propagated hybrid rootstocks affected spurs were counted (a shoot <2.5 cm was nificantly more spurs than those on F1 2/1 the growing and fruiting characteristics of considered a spur). After June drop, the num- (Table 1). Edabriz was intermediate between cherry trees compared to trees on F12/1 ber of fruit remaining was counted. At com- Maxma 14 and F12/1. However, when spur (Franken-Bembenek and Gruppe, 1985; mercial harvest, the fruit from each section of counts were standardized (by shoot length), Schaumberg and Gruppe, 1985). Understand- similar-aged wood were counted and weighed. branches of trees on Edabriz carried more ing the flowering and fruiting response of trees The color of each fruit was rated using the Ctifl spurs per unit shoot length than the other two on new rootstock compared to F 12/1, a stan- cherry color chart, and a mean color score was rootstock. Two-year-old wood had signifi- dard-sized rootstock, is necessary to design determined for each fruit sample. The Ctifl cantly more spurs than either 3- or 4-year-old new pruning and training systems. Our objec- tive was to measure the effect of two potential size-controlling rootstock compared to F12/ 1, a standard-sized rootstock, on the flow- ering and fruiting response of sweet cherry. Materials and Methods The ‘Burlat’ trees used for this study were planted in 1983 at the Ctifl station, Centre de Received for publication 2 Aug. 1993. Accepted for publication 8 Nov. 1993. Summerland Research Station contribution no. 845. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact. HORTSCIENCE, VOL. 29(6), JUNE 1994 611 even with a lower rate of fruit set (87% of the fruit set of F1 2/1), Edabriz still produced more fruit than F12/1. Schaumberg and Gruppe (1985) showed that fruiting of some of the ‘Hedelfingen’ trees on clonal hybrid root- stock was higher than for trees on F1 2/1. Perry (1987) suggested that fruit size gen- erally is not affected by rootstock; instead, it tends to be a result of crop load. Proebsting (1990) reported that ‘Bing’ cherry fruit size is negatively related to yield if leaf area is rela- tively constant. In our study, mean fruit weight was higher on trees on F1 2/1 than on the others; when we analyzed fruit weight using an index for crop load (number of fruit per shoot length) as a covariate, it did not change wood, but when standardized for shoot length, teraction between rootstock and branch age. the results. Thus, fruit from trees on F1 2/1 there was no effect due to wood age. Fruit from trees on FI 2/1 were 26% heavier remained significantly heavier. Fruit weight Branches of trees on Edabriz had almost (mean fruit weight) than fruit from trees on could also be related to cropping history. Yield twice as many flowers per spur than trees on Edabriz or Maxma 14 (Table 3). The fruit from efficiency of trees on Edabriz was five to six the other two rootstock (Table 1). The num- l-year-old wood was significantly heavier than times the yield efficiency of trees on F12/1 the ber of flowers per spur remained constant fruit from any of the other branch portions. previous 2 years ( 1990 and 1991). Fruit weight regardless of the age of the wood. There was no significant interaction between did appear to be related to the amount of Branches of ‘Burlat’ on Edabriz had >20% rootstock and age of wood. current-season’s shoot growth, and current- and >75 % more fruit per branch in absolute When the relationship between mean fruit season’s shoot growth can be used as an indi- terms than similar branches on trees on Maxma weight and current-season’s shoot growth was cation of leaf area. This relationship was stron- 14 and F12/1, respectively (Table 2). When examined, the strength of the relationship de- ger for fruit from trees on Edabriz than for fruit fruit counts were expressed as number per pended on the rootstock. The strongest rela- from trees on F12/1 or Maxma 14. This result centimeter of shoot length, this increase was tionships existed for branches of trees on suggests that mean fruit weight for fruit from 36% and 79%, respectively. One-year-old Edabriz, where average fruit weight was sig- trees on Edabriz could be increased by in- branch sections had the most fruit in either nificantly related to total shoot length (r2 = creasing shoot growth (increasing leaf area) in absolute terms or when standardized to shoot 0.699), number of shoots (r2= 0.502), and the current season. This increase in shoot length. There was a significant rootstock x age mean shoot length (r2= 0.8 18).