>80% germination after 13 years of storage at room temp is quite extraordinary. Usually rapeseed seed viability declines quite substantially after 5-6 years of storage in the cool room. Perhaps you will need to test a number of genera/species/varieties/lines stored at the same time under similar conditions to see some significant differences. You could get a better and firm answer from canola/rapeseed breeders as I am a plant pathologist. It may be genetically controlled but may also depend upon quality of seed at harvest.

Ravjit, about 50 other cultivars stored for the same time at the same conditions (harvested at the same year and the same location) were tested and most of them had 0-1% of viable seeds.

Many of the traits impacting longevity are under genetic control, including fatty acid composition, oil content, seed coat traits and dormancy. There are a couple of books on Brassica spp, that reference some of the original papers on variation in these traits.

Thank you David, fatty acid composition and seed coat traits look good candidates for longevity of seeds control

Some references show that it is possible: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1351444

http://journals.cambridge.org/action/displayAbstract;jsessionid=596DBBE744957DBF70A6C5B1D8F71AAE.journals?fromPage=online&aid=1353096

http://www.plantcell.org/content/16/6/1419.short

Wonderful observations! Definitely there must be genetic basis of the trait. The biochemistry behind it can reveal the factors. The segregating population between the extreme of genotypes can be studied for packing of embryos, Hormones and precursors, or at genomic regions differences.

Just to confirm - we found one more cultivar of head cabbage that has over 50% of seeds viable after 18 years of storage at room temperature.

we linked this trait (longevity of cabbage and rape seeds) to presence/absence of some fatty acids, and finally, I have found an excellent work published by Manuela Nagel et al. at 2018 on the same matter:

Article Machine learning links seed composition, glucosinolates and ...

… analyse germinability and seed composition of a set of 42 oilseed rape (Brassica napus L.) accessions grown under the same single environment and at the same time following a period of up to 31 years storage at 7°C. Mean viability was halved after 27.0 years of storage, but this figure concealed a major influence of genotype. There was also wide variation with respect to fatty acid composition, particularly with respect to oleic, α-linolenic, eicosenoic and erucic acid. Linear regression (rL) revealed significant correlation coefficients between normal seedling appearance and the content of α-linolenic acid (+0.52) and total oil (+0.59). Multivariate regression using artificial neural networks including a radial basis function (RBF), a multilayer perceptron (MLP) and a partial least square (PLS) recognized underlying structures and revealed high significant correlation coefficients (rM) for oil content (+0.87), eicosenoic acid (+0.75), stearic acid (+0.73) and lignoceric acid (+0.97). Oil content or a combination of oleic, α-linolenic, arachidic, eicosenoic and eicosadienoic acids and glucosinolates resulted in highest model fitting parameters R2 of 0.90 and 0.88, respectively. In addition, the glucosinolate content, predominantly in the Brassicaceae family and ranging from 4.6 to 79.5 µM, was negatively correlated with viability (rL = ‒0.43). Summarizing, oil content, some fatty acids and glucosinolates contribute to variations in average half-life (15.2 to 50.7 years) of oilseed rape seeds. In contrast to linear regression, multivariate regression using artificial neural networks revealed high associations for combinations of parameters including underestimated minor fatty acids such as arachidic, stearic and eicosadienoic acids. This indicates that genetic and seed composition factors contribute to seed longevity. In addition, multivariate regressions might be a successful approach to predict seed viability based on fatty acids and seed oil content

This work supports that seed longevity in oilseed rape (Brassica napus L.) is genetically controlled.

Article Seed longevity in oilseed rape ( Brassica napus L.) - geneti...

So far, such feature was found in several more Brassica rapa and B. juncea genotypes, and frequency of viable seeds suggests a recessive gene control.