Fruit set is a key component of essential oil yield from fennel (Foeniculum vulgare Mill.) under Tasmanian conditions. Fruit set in commercial crops is often low, possibly due to incomplete pollination. Fennel flowers are strongly protandrous and a series of flowers must be produced to ensure pollination. The hypothesis tested was that decreasing stand density increases the number of lateral branches, thereby increasing the number of higher order umbels and thus increasing the overlap between the periods of pollen production and stigma receptivity. A field trial was used to examine the number of umbels of each order produced under stand densities of 4, 12, 25, 50 and 100 plants/m 2. Stand density influenced the ratio of pollen producing to pollen receptive umbels and stand densities of 50 and 100 plants/m2 showed a distinct imbalance between pollen production and stigma receptivity. The data collected supported the hypothesis and it is probable that, in commercial crops, fruit set is being reduced by a lack of synchrony between pollen production and stigma receptivity. The highest stand density tested reduced total oil production. We therefore recommend the inclusion of low stand-density strips within standard-density commercial crops.

Item Type:	Refereed Article
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Crop and pasture production
Research Field:	Crop and pasture protection (incl. pests, diseases and weeds)
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Environmentally sustainable plant production
Objective Field:	Environmentally sustainable plant production not elsewhere classified
UTAS Author:	Falzari, L (Dr Linda Falzari)
UTAS Author:	Menary, RC (Professor Robert Menary)
UTAS Author:	Dragar, VA (Dr Valerie Dragar)
ID Code:	29299
Year Published:	2005
Web of Science® Times Cited:	5
Deposited By:	Agricultural Science
Deposited On:	2005-08-01
Last Modified:	2006-05-03
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