An Indoor screening method for reduced dormancy in alfalfa


Bertrand, A. Claessens, A., Rocher, S. 2018. An Indoor screening method for reduced dormancy in alfalfa, In : Brazauskas, G., Statkeviciute, G. Janaviciene, K. (eds) Breeding grasses and protein crops in the era of genomics. Springer International Publishing. pp.209-214

Plain language summary

Forage plants are grown on more than 40% of Canada’s cropland and provide 60% of dairy cattle nutrition and 80% of beef cattle nutrition. The profitability of the dairy and beef industries depends on the yield and persistence of these crops. In Canada, low temperatures cause recurring damage to forage crops and limit their persistence. Improving freezing tolerance is therefore essential under our climatic conditions. For alfalfa, low-dormancy cultivars are productive, but their winter survival is lower than that of more dormant, less productive cultivars. While the phenotypic correlation between these two traits is high, the genotypic correlation is fairly low, suggesting that both traits can be improved simultaneously. New selection approaches that allow the simultaneous improvement of these two traits could accelerate the development of alfalfa cultivars that are both persistent and productive, ensuring greater long-term profitability for Canadian dairy and beef farms. The objective of our research was to develop a standardized recurrent selection approach carried out entirely under controlled conditions to avoid the limitations related to the variability of winter climatic conditions in selection tests in the field. Through field testing carried out at four sites across Canada to measure the fall dormancy and winter survival of the new germplasm obtained through this recurrent selection method, the effectiveness of our method has been validated.


Abstract. Fall dormancy (FD) is a determinant component of alfalfa yield in
northern climate, but selection for that trait is often done at the expense of
freezing tolerance. Field selection for low dormancy is a tedious process that
depends on unpredictable fall conditions to identify less dormant genotypes.
Here we describe two screening methods for low dormancy in alfalfa which can
be entirely performed indoor. Both methods rely on plant exposure to a critical
photoperiod during four weeks to discriminate plants according to their FD
level. One method also includes successive freezing stress to simultaneously
improve freezing tolerance (TF). These approaches can be integrated in a
recurrent selection program to produce populations combining reduced FD and
high TF.