Although considered untenable in the past (Frankel 1970b; Hawkes 1983; Williams 1984), in situ (or on-farm) conservation of crop genetic resources – particularly of landraces and wild crop relatives – is now recognized as a crucial complement to ex situ conservation (Bretting and Duvick 1997; Maxted et al. 1997).
Further north off Portugal, Frobisher's position became untenable, although he captured a prize fresh from Brazil laden with sugar heading to Lisbon on 18 June and a few days later captured a Spanish caravel.
Edgar T. Wherry speculated at length on the hybrid origins of A. bradleyi and other Appalachian spleenworts in 1925, but the scheme he proposed was later found to be untenable, although he did recognize the contribution of A. platyneuron to its ancestry.
We would contend that weight loss without clear proof-of-mechanism would be an unsatisfactory, although clearly not untenable, position for a centrally acting agent.
The Labour whips blame the Tories, although his position only became untenable when Nick Clegg, the Liberal Democrat leader, called on him to resign.
Alternatively, adjuvant therapies may be more effective in the elderly, although this seems a rather untenable hypothesis.
Although this hypothesis may be untenable in this narrowly defined version, it is now well accepted that besides immunological tolerance, induction of Th1-biased immunity against allergens represents an additional strategy exploited by nature to induce normal healthy immunity instead of exaggerated IgE-driven allergic responses.
Although many of his policies seemed untenable, ʿUmar attempted to arrest the disintegration of the Umayyad caliphate by appealing to a broad segment of the Muslim population.
Many Catholic European countries have prohibited surrogacy altogether (although these restrictions are increasingly proving untenable and reform is afoot in many places).
Improving the evidence base would require focussed data collection on parameter values from a given setting where both strategies are implemented or formal comparisons of the two approaches, although the latter could potentially have untenable ethical implications.
