1. Seminar on Genetic variability and adptive potential of temperate and boreal forest tree species 23 – 25 February 2010 Bucharest - Romania “Extreme events in southern European temperate areas: an important role of collections for monitoring the variation of species” Many new problems for phenologists...... Fulvio Ducci & Anna De Rogatis CRA SEL IT – P 12

2. Stone fruit trees such as wild cherry develop their vegetative and fruiting buds in summer and, as winter approaches, shorter day lengthscooler temperatures the already developed buds go dormant in response to both shorter day lengths and cooler temperatures. will not grow in response to mid-winter warm spells Once buds have entered dormancy, they will be tolerant to temperatures much below freezing and will not grow in response to mid-winter warm spells. remain dormant until they have accumulated sufficient chilling units (CU) of cold weather These buds remain dormant until they have accumulated sufficient chilling units (CU) of cold weather. As long as there have been enough CUs the flower and leaf buds are ready to develop normally. If the buds do not receive sufficient chilling temperatures during winter to completely release dormancy, trees will develop one or more of the physiological symptoms associated with insufficient chilling: 1) delayed foliation, 2) reduced fruit set and increased buttoning and, 3) reduced fruit quality.

3. A Southern Apennines clone (MR03) A Dolomites clone (PVN03) A central Apennines clone (VM03)

4. A Chilling Unit: is the amount of hour passed under a certain Temperature level Phenology of domestic cherry in Europe

5. The climate in the Mediterranean Region Average late frost date (24 April) Average early frost date (9 November) 250 m 8050 mm/year 11,5° mean T

6. Phenophases used: 1.Flower Bud scales open 2.Petiole elonged, flowers closed 3.Anthesis 1/3 of flowers 4.Anthesis ½ of flowers 5.1/1 flowers open 6.1/3 flowers released petals 7.½ flowers released petals 8.1/1 small cherries

7. What happen in early autumn 2009? Early frost average date Average date of early frosts CU counting started

8. You passed from temperatures like summer conditions, therefore no dormancy induction messages, to the direct counting of CU. The earliest clones registered that as winter and following eating 10 days as a spring. Another problem is that also BEES recorded that. Rainfalls have facilitated the false message

9. Chilling Units needed? 67 mm precipitations the week before the lower temperatures

10. Late Earlier Spring phenology: according to latitude and mainly altitude Neutral markers 89% of total variation is common to pupolations High individual variation component

11. Clones induced to flower by the false winter/spring short period are the same of previuos surveys and come from: Southern Apennines Areas (usually very cold and snowy, >1500 m Central Apennines, 700 – 1000 m Very low elevations, 20 – 70 m in the middle of PO valley (but with very long winters and and frequent temperature inversion); From the southern slope of Alps, very wide daily temperature range and snowy, 700 – 1000 m

12. Hypotheses Interactions Drought/Rainfalls in autumn?Interactions Drought/Rainfalls in autumn? Interactions Drought/rainfalls-in-autumn/early lower temperatures?Interactions Drought/rainfalls-in-autumn/early lower temperatures? Bud Dormancy not induced by decreasing temperatures?Bud Dormancy not induced by decreasing temperatures? Introgression of ancient early fruit varieties?Introgression of ancient early fruit varieties? Would it be possible characterising clones for a really reduced CU need?Would it be possible characterising clones for a really reduced CU need? Possible uses for genetics?Possible uses for genetics? Why they are more concentrated in some areas at higher altitude and southern aspects?Why they are more concentrated in some areas at higher altitude and southern aspects? More uses of this information?More uses of this information?