Can Fava/ Broad Beans Overwinter in the Northern U.S. Apr 5, 2020 6:52:55 GMT -5
Post by briancady413 on Apr 5, 2020 6:52:55 GMT -5
Another Hardy Fava source, USDA: "...We report here the development of faba bean germplasm tolerant to -25°C after six cycles of bulk selection for overwintering in Central Ferry and Pullman, WA: WH-1 (Reg. No. GP-3, PI 674326), WH-2 (Reg. No. GP-4, PI 674327), WH-3 (Reg. No. GP-5, PI 674328), and WH-4 (Reg. No. GP-6, PI 674329).
"...Discussion: The successful survival of overwintered faba bean grown in southeastern Washington is highly influenced by environmental fluctuations from year to year (Table 1). The crop failure of 2009–2010 was likely the result of air temperature lower than −10°C during germination in October and minimal snow cover and a soil temperature of -7.5°C at a 15 cm depth (Saxena, 1982; Mwengi, 2011). From 2010 to 2013 the winters were relatively mild. The 2013–2014 winter, however, had limited snow cover and was cold enough to distinguish differences between selected and unselected populations.Complicating the influence of prevailing environmental conditions, planting date can also affect overwintering. Late sowings, as was the case at CF in 2013–2014, resulted in crop failure because of inadequate hardening and a -7.5 ° C temperature at seed depth during germination. A general recommendation for much of southeastern Washington is to sow by the first week of October. Generally, this coincides with daily average air (<8°C) and soil (<10°C) temperatures (Murray et al., 1988), but early hard freezes can seriously compromise stand establishment"
From interweb: "Zipcode 99163 - Pullman, Washington is in Hardiness Zones 6a, 6b, 7a and 7b"
Yet more: Abstract: "Winter-hardy faba bean (Vicia faba L.) from northern Europe is represented by a rather narrow gene pool. Limited selection gains for overwintering below −25 °C have restricted the adoption of this crop. Therefore, the faba bean collection maintained by the USDA-ARS National Plant Germplasm System (NPGS) was utilized to broaden this genetic base by identifying potentially new sources of winter-hardiness using a modified mass selection scheme. From an initial source population, bulk-harvested micro-plots of 466 NPGS accessions, four different bulks were formed by harvesting seeds from plants that survived at four locations representing a range of overwintering selection environments across southeastern Washington. These four bulk populations were then mass selected for three cycles based on winter survival along with a selected group of advanced northern European populations or breeding lines at two southeastern Washington locations with divergent climates. This procedure generated breeding materials with winter-hardiness comparable to the northern European populations. We observed that Northern European populations showed slower annual gains in percent survival (<5%) than NPGS bulks (>5%). Further, the frequency of large seeded populations (>80 g × 100 seed⁻¹) was reduced over time, suggesting an association between seed size and overwintering. The breeding materials generated by mass selection are useful for the future improvement of faba bean as a fall-sown pulse or cover crop."