Page 26 - Breeding and regulatory opportunities, Renaud

Chapter 1

farmers refrain from use of chemical inputs for weed management and pest

and disease control, thus varieties must perform under diferent management

conditions compared to conventional farms. Since the organic farming sector is

comprised of diverse types of organic growers (ranging from small-scale direct

market producers, through wholesale to large-scale operations producing for

industrial processing enterprises), and since organic farmers have fewer tools at

their disposal to inluence their production environment to it their crops, their

variety needs difer signiicantly from those of their conventional counterparts

(Drinkwater et al., 1995; Wolfe et al., 2008).

In the case of broccoli, at the start of the study it was known that some organic

farmers’ desired traits were the same as those of conventional producers,

such as drought tolerance, insect and disease resistance or high yield. Other

characteristics were thought to be more important to organic producers than

to conventional growers: for instance, vigorous growth and ability to perform in

soils with potentially low or luctuating mineralization rates of nutrients, or the

ability to cover the soil and withstand weed competition by having less erect

architecture than displayed by modern broccoli hybrids. The few studies to

articulate the required cultivar traits for organic farming systems had focussed

mainly on arable crops, especially cereals (Wolfe et al., 2008); only a few had

dealt with desired vegetable crop traits (e.g. Osman et al., 2008, for onions). No

studies had been published on the desired traits for organic broccoli or other

Brassica crops.

Some studies comparing performance of genotypes in organic and

conventional management systems had shown that for certain traits, cultivar

rank varies between the two management systems (e.g. for winter wheat:

Murphy et al., 2007; Baresel et al., 2008; Kirk et al., 2012; for lentils: Vlachostergios

and Roupakias, 2008; for maize: Goldstein et al., 2012), others had shown no

diferences in ranking of performance (for maize: Lorenzana and Bernardo,

2008; for cereals: Przystalski, 2008; for onions: Lammerts van Bueren et al.,

2012). The inconclusive results of these studies raise questions as to the need

for cultivars to be bred with broad adaptability or speciic adaptation in order

to meet the requirements of regional organic management and end uses.

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