Deacclimation rates to quantify dormancy transitions in several grapevine species
Description
Data from the paper: Kovaleski AP, Reisch BI, Londo JP. (in press) Deacclimation kinetics as a quantitative phenotype for delineating the dormancy transition and thermal efficiency for budbreak in Vitis species. AoB PLANTS. Buds of four different species were collected at up to 9 levels of chill accumulation during the dormant seasons of 2014/15, 2015/16, and 2016/17 (see Supplementary Table S1 for details on collections). V. vinifera L. ‘Cabernet Franc’, ‘Cabernet Sauvignon’, ‘Riesling’, and ‘Sauvignon blanc’ were collected from local vineyards (42.705N, 76.973W; and 42.845N, 77.004W), while V. aestivalis Michx. (two clones: PI483138, PI483143), V. amurensis Rupr. (three clones: PI588632, PI588635, PI588641), and V. riparia Michx. (four clones: PI588275, PI588562, PI588653, PI588711) were collected from the USDA Plant Genetic Resources Unit in Geneva, New York. Upon collection, canes were cut into single- or two-node cuttings, randomized to prevent bias associated with node selection, and placed submerging the basipetal cut surface in cups of water. The cups were placed into growth chambers at 2, 4, 7, 8, 10, 11, 22, or 30 °C. Not every genotype or temperature was used at all collection points. Differential thermal analysis was used to estimate the cold hardiness of individual buds as represented by their low temperature exotherm [LTE; see Mills et al. (2006) for details], the standard measure for grapevine. Briefly, buds are excised from the cane and placed on thermoelectric modules in plates. The plates are placed in a programmable freezer and subjected to a cooling rate of −4 °C hour−1. Changes in voltage due to heat release in the freezing of water are measured by the thermoelectric module and recorded using a Keithley data logger (Tektronix, Beaverton, OR) attached to a computer. Between 4 and 8 buds were sampled at any time point per treatment to determine mean LTE, and the intervals between measurement days varied between chill accumulation level and temperature treatment. An experiment was also designed to compare temperature effects on budbreak of buds collected from grapevines that were considered to be fully chilled (1440 chill accumulation). Buds held at constant temperatures (2, 4, 7, 11, 22 °C) had their budbreak recorded following the modified E-L scale (Coombe and Iland, 2005) for all V. vinifera and V. riparia. Five buds were randomly selected and E-L number recorded in the same sampling interval as for LTE until buds were past stage 3 or bud material was exhausted.