Genetic variation for secondary seed dormancy and seed longevity in a set of black‐seeded European winter oilseed rape cultivars

Abstract

Secondary seed dormancy in oilseed rape is a phenomenon that allows seeds to survive in the soil for many years without germination. Following soil cultivation, dormant seeds may germinate in subsequent years, and they are the main reason for the occurrence of volunteer oilseed rape plants in successive crops. Inheritance of secondary dormancy may be related to seed longevity (SL) in the soil. Genetic reduction in secondary dormancy and SL could provide a mean to reduce the frequency of volunteer plants and especially the dispersal of transgenic oilseed rape. The aim of the present study was to analyse secondary dormancy, germination rate and SL of 28 black‐seeded winter oilseed rape cultivars using in vitro laboratory tests. The material was tested in field experiments at six different locations in Germany in 2008/2009. Significant effects of the genotype and the location on all traits were found. Heritability was high for secondary dormancy (0.97) and moderate for germination rate (0.70) and SL (0.71). Results indicate that a selection for low secondary dormancy would be effective.

Which soils are comfortable for oilseed rape seeds (Brassica napus) to survive?

“…Accessions with low fibre content seemed to have survived to a lesser extent than accessions with high fibre content, though molecular-genetic studies did not show a link between fibre content and seed dormancy as a pre-condition for seed survival (Schatzki et al 2013). The variation among the new trait accessions (Figure 2) can be also well explained by the known genotypic variation and disposition to dormancy that ranged between 1% (Yellow 1) and 59% (Thick; data not shown) and that significantly correlated with seed survival (Weber et al 2011).…”

Effects of pre‐ and post‐dispersal temperature on primary and secondary dormancy dynamics in contrasting genotypes of Arabidopsis thaliana (Brassicaceae)

“…) and sensitivity to secondary dormancy induction (Momoh et al . ; Penfield & Springthorpe ; Schatzki et al ., ).…”

Comparison of the crop speciesBrassica napusand wildB. rapa: characteristics relevant for building up a persistent seed bank in the soil

“…Pekrun et al (1998) exposed B. napus seeds to a 0 -4-week period of darkness and then tested germination in the dark. In a recent paper, Schatzki et al (2013) demonstrated genetic variation in the ability of B. napus cultivars to develop dark dormancy in polyethylene glycol, under darkness and osmotic stress. Studies on the effect of management on seed bank persistence and volunteer emergence found that without tillage the seed bank of B. napus is essentially zero (Pekrun et al, 1998;Lutman et al, 2003Lutman et al, , 2005, indicating that seeds cannot develop secondary dormancy when dispersed on top of the soil.…”

“…An interesting option would be to induce secondary dormancy in the seeds using the polyethylene glycol methods of Schatzki et al (2013) and others. Developing a long-lasting seed bank is a weedy character and information on this is relevant for the ERA.…”

“…Mature non-dormant seeds may experience secondary dormancy after seed dispersal; that is, due to exposure to some environmental cue an initially non-dormant seed no longer germinates under conditions that were, at first, conducive for germination. Several authors (for instance, Pekrun et al, 1997, Gruber et al, 2004Schatzki et al, 2013) showed that secondary dormancy can be induced in seeds of B. napus by keeping them in the dark for 2 weeks in a polyethylene glycol medium that imposes oxygen and water stress (osmotic potential of 2 0.5 MPa, i.e. Adler et al (1993) found that 4 weeks of cold stratification decreased subsequent germination of wild B. rapa seeds but not that of B. napus cultivars.…”