The role of difference genotypes of Brassica carinata and Brassica juncea as biofumigant crops in contrasting ecosystems

Abstract: This study analyzed the production of plant tissues (above and below ground) and the concentration and profile of glucosinolates of two genotypes of B. carinata A. Braun and B. juncea L. Brassica genotypes were grown in two locations of south Andalusia with different weather and soils (dehesa – oak open woodland – and valley), during two campaigns (2013 and 2014). Samples were taken in full bloom, at the time of incorporation of the plant tissues into the soil. The genotypes of both species tested have shown different productions between locations and years. Total plant production was higher in valley than in dehesa. In dehesa, production was low in the first year, due to a deficient initial plant establishment. Above-ground biomass ranged between 25-8 T DM/ha in valley and between 6-0.2 T DM/ha in dehesa. Below-ground biomass ranged between 9-3 T DM/ha and 1.7-0.1 T DM/ha in valley and dehesa respectively. Genotypes of B. juncea reached higher production than those of B. carinata in dehesa, and similar values in the valley. In both areas, sinigrin was the main glucosinolate in aerial and root tissues. Total sinigrin that can be incorporated into soil was estimated around 270-50 kg DM/ha in valley and 39-0.5 kg DM/ha in dehesa. The results pointed out that B. juncea can play a better role as a biofumigant plant against P. cinnamomi than B. carinata, especially in dehesa area.