rv. To date the only indication of linkage observed has been between rv and e. The F2 is small and the linkage chi square is not significant. The deviation is relatively large, however, suggesting a co. value of about 32 units. Additional progenies will be planted shortly to permit a more reliable test for linkage.
yv, No associations have been detected thus far except in an F2 segregating in repulsion for yv and wt. The data are incomplete because it was necessary to rogue the population to yv seedlings. Of 47 yv seedlings thus obtained only 3 were wt. Square-root analysis of the recombination class gives, as a very rough approximation, a linkage intensity of 24%. This relationship obviously needs a more extensive test.
dv. Additional data confirm that dv is in chromosome linkage group 2(I). According to a three-point F2, the positions are dv - 6 - m - l - d with about 9 units between dv and d. Since d and m were coupled against dv the figures for d-m, are more reliable than for the other two combinations. These estimates plus the fact that no dv - m - + individuals, part of which would represent a double crossover class, were encountered in an F2 of 1654 suggest that the above order is correct.
tf. Crosses made by both Dr. Dennett and us prove that tf and ct are allelic if not identical genes. Since tf was the symbol first applied (and is more appropriate anyway), we are proposing it for this mutmt. The linkage we reported last year between tf and wilty was confirmed this year, but it turns out that the wiltiness is not conditioned by wt but by some other gene present in the tf stock. In this new wilty material the leaves curl abaxially instead of adaxially as in the case of wt. According to a small coupling F2 the linkage intensity between tf and the new wilty is about 13%.
dl. The linkage between dl and l reported last year prompted us to try dl against bu. Result: rather tight linkage with a co value of about 9%. In addition, F2 data give a hint of linkage (not significant) between dl and al of about 40 units. For dl-l all data so far yield a value of 38 units. According to all known tests l and al are independent. The loci on 8(VI & VIII) are then presumably l - 30 - bu - 9 - dl - 40 - al.