Plantbreeding at Svalöf - continued...

Such traces in the register evince that a separate space of symbolic representation had to be opened by Nilsson-Ehle to explore the regime of Mendelian combinatorics in order to 'see' how assumed factors might combine to reproduce the empirically observed distribution of characters. Such distributions, that is, were not simply to be 'seen' from what the register itself presented as data. They were rather developed in a trial-and-error fashion by performing mathematical permutations with symbolical representations in a separate paper space and comparing the results with the data contained in the register. The recording system instituted at Svalöv, however, did not leave much space for such manipulations. This becomes especially clear, when we look at how Nilsson-Ehle's experiment with the cross 0353 x 0668 proceeded: For 1907, the corresponding field-book is not preserved, and the notes on the continued experiment contained in the 1908 field book offer a disappointment. Except for a few notes on the cultivation and development of the plants, it only offers the following dry remark: 'Numbers 272-317 of cross 0353 x 0668 have been handled from a theoretical viewpoint. See separate lists (Korsningsnumren 0353 x 0668 272-317 är bearbetad ur teoretisk synpunkt. se särskilda listor)'. Moreover, Nilsson-Ehle returned to the pedigree method in the third hybrid generation, i.e. the separate cultivation of types selected for a specific, overall character (in this case 'earliness'). This was a move that clearly contradicted Mendelian methodology, which demanded strict renunciation of any kind of selection. Nilsson-Ehle also returned to the old pattern of record keeping: For each parcel in 1906 a taxonomic characterisation of different types (A, B, etc.) was carried out, which also, but not only, and especially not always (namely in those cases, were it did not make a difference), included seed colour. The segregation ratios for seed colour in the third hybrid generation had to be 'distilled' painstakingly from the 46 field book entries descending from the 1903 cross of pedigrees 0353 and 0668, and were anyway, with the low absolute numbers and the previous selection, anything else than trustworthy (see Müller-Wille 2005 for details).