Variation in seed glucosinolate concentrations of Indian mustard (Brassica juncea (L.) Czern. + Coss.)

Abstract

Detailed analysis of the seeds of 128 individual plants of an Indian mustard accession, PI 183117, grown at a field site with adequate soil sulfur, revealed a wide variation in both the composition and total concentrations of seed glucosinolates. An apparent somaclonal variant of the same accession is also reported. Selection of seeds from this variant resulted in the isolation of plants with significantly lower seed glucosinolate levels and a greatly reduced variability in both content and proportions of the major seed glucosinolates, compared with the parental line. Averaged over the field experiment, and 2 glasshouse experiments (the second with 2 soil sulfur levels), the reduction in total glucosinolate concentration was 22%. Neither the effect of additional sulfur, nor its interaction with the test populations, was significant. Assuming that the variation in total seed glucosinolate concentration between plants within the selection was entirely environmental, the lower limit of the broad sense heritability in the original accession was estimated as 29.5%. Additional genetic variation appears to be necessary to reduce the seed glucosinolate content to the maximum level specified under the 'Canola' standard for rapeseed.