Some additional data on chromosome VII

1. Some additional data on chromosome VII. Field counts.

(a)	+ + +	x v5 ra gl
	v5 ra gl	x v5 ra gl

	0	1	2	1 & 2	Total

	686	52	41	3	782
		6.7%	5.2%	.4%

(b)	+ + +	x ra gl ij
	ra gl ij	x ra gl ij

	0	1	2	1 & 2	Total

	169	10	35	4	218
		4.6%	16.1%	1.8%

(a)	v5	7	ra	6	gl
(b)		ra	6	gl	gl	18	ij

(c) Antherless (at), unlinked, is very clear cut and gives sharp classifications in the field. An F₂ involving at, v5, and ra showed at to be independent of the other two genes.

(d) In making notes on v5, it is best not to wait until toward the close of the growing season. A number of plants often develop stripes only on the lowest leaves. These should be marked, since if seasonal or soil conditions are adverse, the lower leaves may die and such plants will be classed as green.

A. C. Fraser

(a) Any virescent-1 stock coming from the Co-op or from me must be used cautiously; there seems to be another virescent mixed in. Can anyone send me a stock known to be v1?

(b) In a backcross of about 400 seedlings the alien virescent mentioned above showed no linkage with wx. Of the 182 virescents in this backcross, 108 of them showed normal green stripes. This is suspiciously close to a 9:7 ratio.

(c) A number of chlorophyll types (g, w, l and v) are being inbred by repeated backcrossing to the same inbred. The purpose is to get genetically uniform types for physiological study. Seed of the various types (twice backcrossed) are available to any one desiring it.

(d) In connection with the above mentioned inbreeding program, I should like very much to obtain seeds of two or three different pale greens (esp. lethal ones) and of any other green seedlings that die. Will several of you who have such stocks send in a few seeds, please?

(e) Can anyone send me some g3 seed? That in the Co-op seems not to carry g at all.

(f) A summary table of all my slit blade cultures is given below to show some of the abnormal ratios obtained. The division of the F₂ cultures into groups is arbitrary and hard to justify except on the grounds of convenience. Note that both B.C. & F₂ totals show too many Sb plants.

	Sb	sb	Ratio
Sum of B.C.	495	384	1.29:1

Sum of F₂ (less than 4:1)	3083	1001	3.08:1

Sum of F₂ 4:1-7:1	2138	458	4.67:1

Sum of F2 (greater than 7:1)	633	69	9.2:1

Sum of all F₂	5854	1528	3.83:1

(g) Small F₂'s last summer showed no linkage of bm3 or wa to sh, wx, or gl4; nor of sb to lg2, Ts5, j, sh, wx, gl4, or gl. Several attempts have failed to show any linkage of my gl4 to yg, sh, or wx. (This is not the gl4 of Burnham.)

John Shafer