Page 124 - Breeding and regulatory opportunities, Renaud

Chapter 4

4.2 Material & methods

4.2.1 Plant Material

Twenty-three broccoli cultivars including open pollinated (OP) cultivars, inbred

lines, and Fhybrids were included in the ield trials Table 4.1). These cultivars
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were selected to encompass varietal diversity in the targeted trial regions by

organic and conventional growers as well as to represent diverse genotypes

and phenotypes that difered in their year of commercial introduction and the

commercial seed company of origin.

4.2.2 Field Trial Locations

The cultivars were grown paired organic and conventional ields at two

U.S. locations [Maine (ME)-Monmouth (Latitude 44.2386oN, Longitude

70.0356oW; elevation 61 masl); Oregon (OR)-Corvallis (Latitude 44.5647oN,

Longitude123.2608oW; elevation 76 masl)] in fall and spring during 2006-

07 and 2007-08 growing season. The paired organic and conventional ields

within each location had similar soil types (ME: Woodbridge Fine Sandy Loam;

OR organic: Malabon Silty Clay Loam, OR conventional: Chenalis Silt Loam)

and comparable climatic conditions (one degree day or less between sites and

negligible precipitation diferences). In ME both the conventional and organic

trials were at University of Maine Cooperative Extension, Highmoor Farms

Research Station and adjacent to one another. The OR conventional ield trials

were located at the Oregon State University Vegetable Research Station and at a

local organically managed commercial farm within 5 km and with a comparable

elevation (<50 foot) for the organic ield trials. Both organic trial sites had been

managed organically for over ive years and were mature organically managed

production systems at the onset of the study.

4.2.3 Field Design

Field trials consisted of the 23 broccoli cultivars arranged in a randomized

complete block design with three replicates under both organic and

conventional management at ME and OR locations during 2007-08 growing

season. An individual treatment plot contained 36 plants that were planted in

three rows of 12 plants at 46 cm equidistant spacing within and between rows.

In 2006, only 18 of the 23 cultivar entries were established in the OR and ME

ield trials, and there were only two replicates in the OR organic 2006 ield trial.

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