1. WP2 G&H April 20021 Garlic life cycle and flowering physiology Rina Kamenetsky The Volcani Center ISRAEL Haim D. Rabinowitch The Hebrew University ISRAEL

2. WP2 G&H April 20022 - Flowering as the first stage in sexual reproduction of garlic - Flowering is a complex phenomenon that depends on developmental stage, temperature, daylength, genetic factors, nutrients - Extensive research has been performed on flowering physiology of onion, while very little is known about garlic and other Allium crops

3. WP2 G&H April 20023 Inflorescence of garlic Topsets Floral buds Garlic (Allium sativum) is a completely sterile plant, propagated only vegetatively Increase of genetic variation occurs only via random or induced mutations, new cultivars are bred by clonal selection

4. WP2 G&H April 20024 Garlic clones are classified according to their ability to bolt: 1. Complete bolting: long stalk with many flowers and topsets 2. Incomplete bolting: thin short stalk with a few large topsets 3. Nonbolting plants: producing only cloves inside incomplete scape (Takagi, 1990)

5. WP2 G&H April 20025 -2 0 C 20C20C40C40C90C90C20 0 C Floral scape Bulb Low storage temperatures promote leaf elongation after planting Scape elongation and bulbing were significantly faster after storage at lower temperatures

6. WP2 G&H April 20026 17/9 0 C SD - LD 17/9-20/12-23/15 0 C SD - LD- LD 20/12-23/15 0 C SD-LD 17/9-20/12-23/15 0 C SD In bolting type, daylength plays a dominant role in promotion of scape elongation Interactions between growth temperatures and daylength

7. WP2 G&H April 20027 2001 - 2002 Experimental design 20/12 0 C or 20/12 0 C - 23/15 0 C SD 1 week LD SD SD 2 weeks LD SD 20/12 0 C or 20/12 0 C - 23/15 0 C SD 3 weeks LD SD 20/12 0 C or 20/12 0 C - 23/15 0 C SD 4 weeks LD SD 20/12 0 C or 20/12 0 C - 23/15 0 C

8. WP2 G&H April 20028 Control treatments: 20/12 0 C 20/12 0 C - 23/15 0 C 20/12 0 C 20/12 0 C - 23/15 0 C SD LD SD LD

9. WP2 G&H April 20029 Floral initiation, differentiation and development were examined by light and scanning electron microscopy Flower primordia Developing topsets

10. WP2 G&H April 200210 Plants exposed to SD never bolted and produced many axillary leaves

11. WP2 G&H April 200211 A B 20/12 - 23/15 0 C, LD 20/12 - 23/15 0 C, SD - 2 weeks LD - SD 1 cm

12. WP2 G&H April 200212 TreatmentLeaf number prior to floral initiation Maximal scape length Sprouted cloves Non-sprouted cloves SD - LD1054.310 SD 13010 LD757.410 SD - 1 w LD - SD1031.510 SD - 2 w LD - SD1354.79 SD - 3 w LD - SD1260.59 SD - 4 w LD - SD1356.09 Growth temperatures 20/12 – 23/15 0 C

13. WP2 G&H April 200213 SD - 2 or 3 weeks LD - SD 1 cm SD - 4 weeks LD - SD SD - LD (after 10 weeks) 1 cm SD - 1 week LD - SD 1 cm