Page 120 - Breeding and regulatory opportunities, Renaud

Chapter 4

Broccoli cultivar performance under organic and conventional management

systems and implications for crop improvement

Erica N.C. Renaud, Edith T. Lammerts van Bueren , M. João Paulo, Fred A. van Eeuwijk,

John A. Juvik, Mark G. Hutton, James R. Myers

(Crop Science, Vol. 54, July-August 2014, DOI: 10.2135/cropsci2013.09.0596)

Abstract

To determine if present commercial broccoli cultivars meet the diverse needs

of organic management systems such as adaptation to low nitrogen input,

mechanical weed management and no chemical pesticide use, and to propose

the selection environments for crop improvement for organic production,

we compared horticultural trait performance of 23 broccoli (Brassica oleracea

L. ssp. italica) cultivars (G) under two management (M) systems (organic

and conventional) in two regions of the USA (Oregon and Maine), including

spring and fall trials. In our trials, location and season had the largest efect

on broccoli head weight with Oregon outperforming Maine and fall trials

outperforming spring plantings. M main efects and G × M interactions were

often small but G × M × E (location and season) were large. Cultivars with both

greater head weight and stability under conventional conditions generally had

high head weight and stability under organic growing conditions, although

there were exceptions in cultivar rank between management systems. Larger

genotypic variances and somewhat increased error variances observed in

organic compared to conventional management systems led to repeatability

for head weight and other horticultural traits that were similar or even higher

in organic compared to conventional conditions. The ratio of correlated

response (predicting performance under organic conditions when evaluated in

conventional conditions) to direct response (predicted performance in organic

when evaluated under organic conditions) for all traits was close to but less than

1.0 with the exception of bead uniformity. This would imply that in most cases,

direct selection in an organic environment could result in a more rapid genetic

gain than indirect selection in a conventional environment.

Keywords

Crop growth and development, other crop management, plant and

environment interactions, sustainable agriculture, crop genetics

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