By Golnaz Badr1
1Cornell Lake Erie Research and Extension Lab, CLEREL, Portland, NY 14769
The study of natural phenomena that recur in plants is known as phenology1. For Concord grapevine, phenology is the study of the annual sequence of its development. Phenology seeks the cause of variation in the timing of developmental stages by analyzing the correlation between weather and timing of growth events. Such a study aims at: 1) observing the timing (dates) of growth events; 2) calculate the intervals between the growth events; 3) keep a record of key phenology events for various locations; and eventually 4) understand how Concord reacts to various environments (meso-climate).
Key growth and development stages for Concord grapevines include budbreak, bloom, veraison. Having knowledge of phenology events at your vineyard will help you better design your vineyard, plan for labor and equipment requirements, and also improve your vineyard management by adjusting the timing of various cultural practices that you embark on during growing season.
Concord bud break is defined as the time when half or more of leaf edge is exposed (Figure 1). Bloom is defined as when 50% of florets are open (Figure 2), and veraison is defined as the time when 5% of berries have color and it is regarded as the onset of maturity for berries (Figure 3). This information has been collected at Cornell Lake Erie Research and Extension Lab (CLEREL) for more than 40 years. However, we highly encourage you to keep record of the key phenology events at your own vineyard as it might be slightly different from the records for CLEREL depending on your site geographical properties such as elevation, closeness to Lake Erie or other water bodies, the slope and direction of the slope (aspect) at your site, and also the soil type.
The average historical bud break date is May 5 for vineyards at CLEREL (Table 1), this year however, budbreak did not occur until May 9th. So, the take-home message here would be: if you are already recording the key phenology dates at your vineyard, good job, keep it up! If no, it would be a great idea to start recording this information. Consequently, in a couple of years down the road you would recognize how vital this information would be for your decision making and cultural practices. So why not start this 2018 growing season! Yes, you can do it!
1(Greek phainesthai= to appear, logos=knowledge, teaching)
Table 1: Key phenological events recorded at Lake Erie Research and Extension Lab.
|Bub-break to Full-bloom (days)||40||32||62||30|
|Bud-break to veraison (days)||110||98||128||30|
|Full-bloom to veraison (days)||69||63||79||16|