In the Back Cross Orchard, every year the survival and data about height and diameter at breast height or DBH (at 4.5 ft by convention) are recorded. Thus over time, growth rates can be calculated. In addition, certain aspects of form and timing of events (phenology) are important. One of the characteristics that reflects Chinese inheritance in the American-Chinese hybrids is the timing of bud break, and identifying trees with early bud break is important.
Below is a “pivot table” from an Excel File for the Meades Landing Orchard. Pivot tables provide handy summaries of data collected, and this one shows cumulative mortality and growth information.
The Slide show of Bud Break pictures (taken by Kendra Gurney, Northeast Science Coordinator) and the attached PDF file make it look easy to rank trees, but the tree has a wide variety of expression in its many buds at any given time, so working out a consistent strategy for ranking can be a challenge. Chinese traits, like early leafing out, are traits that should be selected against for breeding purposes. A single collage showing all stages is helpful for field work to match with the tree being ranked.
Meades Landing (KYML08) Pivot table through Oct 2011
|Cross_Code||Number Planted||Cumulative Count of Dead||Average Growth Rate 10 to 11||Average Change in DBH 10 to 11||Average Growth Rate per yr||Mortality|
|GL239 x KYFLEM1-A||55||9||3.45||0.46||2.87|
|JB216 x KYHart1||100||17||4.31||0.60||3.10||16.4%|
|KYNELS1-C x KYBATH1-A||1||3.83||0.52||3.17||17.0%|
|KYNELS1-C x KYHART1-A||6||1||4.01||0.58||3.79|
|KYNELS1-C x KYLEWI1-A||3||2.24||0.42||3.20||16.7%|