The cracking quality of the nuts from the trees in this study was tested
on a random sample of nuts from each crop that was collected and brought
back to Norris. The nuts of each sample were weighed and the average nut
weight computed. The nuts were then cracked in a hand-cracking machine,
and kernels that could be extracted with the fingers were removed and
weighed.[13] From this weight was computed the first-crack marketable
kernel percentage. The nuts that still contained kernels were recracked
and the remaining kernel removed. All kernels, including crumbs, were
then weighed in order to compute the total kernel weight and kernel
percentage. Finally, all of the quarters extracted were counted, and the
average number of quarters was computed. Kernels recovered at first
crack and the average number of quarters extracted indicate the relative
ease of extraction of kernels.
Cracking quality of walnuts for individual sample trees averaged by crop
years are presented in Table 1. Nuts of all crops collected from four
trees, 57, 58, 60, and 139, were shriveled or abnormal, and afforded no
test of nut quality during the six-year period. Thus, nut quality data,
based on 440 nut crop samples, are complete for 128 of the 132 sample
trees. From this study, the average common black walnut in the Tennessee
Valley has a nut weight of 17 grams, a kernel weight of 3.3 grams, a
total kernel content of 20 per cent, a marketable kernel recovery at
first crack of 17 per cent, and a quarter recovery of unbroken quarters
averaging 1.8.
[Footnote 13: The kernels were extracted over a 6-mesh wire screen. In
commercial cracking, kernel pieces passing through this type of screen
are not marketable as kernels.]
Table I--Yield of Nuts and Kernels, and Cracking Quality of Nuts from
132 Sample Trees of Common Black Walnut in the Tennessee Valley
_________________________________________________________________________
Tree
_____________________
Diameter
at 4-1/2 ______________________________________________________
Sample ft.
number av. yr. 1940 1941 1942 1943 1944 1945 Av. yr.
_________________________________________________________________________
inches pounds pounds pounds pounds pounds pounds pounds
1 20.4 27 16 2 95 5 3 25
2 14.9 43 43 26 45 42 23 38
3 9.3 22 12 8 22 6 29 17
5 11.2 54 0 61 0 33 7 26
6 13.6 28 1 72 0 16 1 20
8 13.2 50 28 23 41 76 45 44
9 13.2 36 50 40 28 33 7 32
10 22.9 29 25 0 0 6 15 12
11 6.1 2 4 12 2 4 1 4
12 17.4 110 18 128 40 100 49 74
13 14.5 98 5 83 50 46 128 68
14 12.2 1 0 12 3 2 98 19
15 11.6 38 46 44 106 0 63 50
16 15.7 130 0 106 25 135 33 72
17 12.0 1 66 4 100 2 61 39
18 7.8 20 0 40 21 33 4 20
25 8.6 13 0 82 0 0 0 16
26 20.7 0 36 46 90 0 67 46
27 8.4 0 1 26 2 0 22 8
28 8.0 0 11 1 19 0 12 7
29 9.2 0 17 22 21 2 19 14
30 15.2 150 25 200 0 102 15 82
31 18.0 33 194 14 259 0 135 106
34 16.4 0 108 0 25 0 129 44
37 19.7 0 0 31 0 0 0 5
38 9.1 2 0 14 0 47 0 10
39 17.7 151 0 80 0 56 0 48
40 16.5 88 0 50 5 37 6 31
41 9.5 60 0 74 0 67 0 34
42 14.5 123 0 170 0 119 0 69
______________________________________________________________________________
Av. Filled nuts Complete crack
Kernel _________________ ________________________
yield First-
bearing In terms crack Crops
yrs. of total Average marketable Kernel tested
number only weight weight kernel weight Kernel Quarters basis
______________________________________________________________________________
pounds percent grams percent grams percent number number
1 2.2 6 17 21 3.7 22 2.9 2
2 4.9 50 14 17 2.6 19 1.3 5
3 2.2 63 16 18 3.3 21 2.0 7
5 7.9 67 16 23 4.5 27 1.1 3
6 4.9 92 14 22 3.2 23 2.8 4
8 5.6 59 24 17 5.0 21 3.0 7
9 6.1 56 16 20 3.6 23 1.3 5
10 1.6 36 13 15 2.6 19 0.6 2
11 0.8 99 14 16 2.7 19 1.4 7
12 16.3 95 18 17 4.2 23 1.5 7
13 17.9 92 19 25 5.2 28 2.9 7
14 4.9 91 19 18 4.3 22 2.4 3
15 11.8 96 17 19 3.4 20 2.1 6
16 20.0 94 24 19 6.0 25 2.3 6
17 8.4 97 13 17 2.7 20 2.5 7
18 5.3 85 15 24 4.0 26 2.5 4
25 9.6 93 18 16 3.8 21 2.5 4
26 5.5 42 16 14 3.1 18 0.6 4
27 2.7 95 17 19 3.7 21 1.2 3
28 1.7 99 9 14 1.6 18 1.6 4
29 3.4 100 11 15 2.2 21 1.2 4
30 19.9 77 19 17 4.3 23 2.3 3
31 25.1 90 20 15 4.5 23 1.3 4
34 16.8 73 20 17 4.0 20 2.5 2
37 6.2 100 16 16 2.8 18 3.4 2
38 4.5 63 18 14 2.8 15 2.3 2
39 15.0 87 19 14 3.5 18 2.2 3
40 4.9 82 20 13 3.1 15 2.3 3
41 9.1 73 16 17 3.0 19 2.5 3
42 28.4 86 19 21 4.5 24 3.3 3
46 13.8 14 18 15 36 12 12 18
47 9.8 15 0 39 0 20 2 13
48 13.6 25 34 50 52 17 96 46
49 6.6 14 9 16 4 19 0 10
50 9.5 29 0 13 25 0 57 20
51 11.2 11 13 11 0 24 0 10
52 13.3 25 8 0 84 0 14 22
56 13.4 15 8 0 12 4 6 8
57 16.7 162 5 103 17 74 4 59
58 12.0 42 2 30 6 20 2 17
59 9.4 2 8 4 8 2 8 5
60 9.6 1 1 3 0 2 0 1
61 10.6 2 2 20 1 10 0 6
62 12.4 27 6 23 7 13 0 13
63 12.1 2 0 0 0 0 0 0
64 11.8 18 2 37 0 21 0 13
65 17.8 130 53 101 9 107 0 67
66 9.6 31 0 25 1 13 5 12
67 9.4 89 0 7 7 10 11 21
69 13.7 70 2 104 4 30 2 35
70 16.1 72 2 11 95 0 68 41
71 15.2 7 1 43 1 0 1 9
76 8.1 7 0 6 0 9 0 4
77 11.2 40 0 21 6 4 23 16
78 11.4 34 0 40 0 31 2 18
79 16.4 28 0 24 0 11 22 14
80 11.4 132 44 110 8 189 42 88
86 24.9 191 0 282 0 64 110 108
87 14.0 45 0 107 0 31 9 32
89 8.4 1 8 2 39 0 44 16
90 13.2 11 6 72 8 13 7 20
91 12.4 68 5 200 3 54 22 59
92 17.6 18 74 138 76 2 126 72
93 10.9 30 0 48 3 26 0 18
94 7.2 0 36 0 21 0 53 18
46 1.7 51 17 16 2.8 17 2.8 4
47 3.8 97 11 17 2.2 20 1.0 3
48 8.2 83 13 16 2.6 20 1.3 4
49 2.0 80 18 16 3.7 20 2.0 3
50 3.7 72 17 19 3.6 21 3.4 3
51 1.9 49 18 19 4.2 23 1.6 3
52 6.0 80 18 16 3.2 18 1.3 2
56 0.6 13 22 20 4.8 22 3.0 1
57 4 0
58 9 0
59 0.4 20 27 19 5.6 21 3.0 2
60 0.0 0 22 15 3.4 15 3.9 1
61 0.2 48 14 9 2.0 14 1.5 2
62 0.4 15 25 19 4.6 19 3.8 2
63 0.5 94 13 21 3.2 24 3.1 2
64 3.1 70 21 20 5.1 24 3.2 3
65 7.9 58 23 15 3.7 16 3.4 3
66 1.6 34 24 18 4.6 19 3.7 3
67 2.2 31 20 18 3.7 18 3.6 3
69 8.6 92 21 21 5.4 25 1.9 3
70 9.2 87 18 16 3.4 20 1.5 3
71 2.0 88 14 16 2.6 19 1.9 3
76 1.4 94 13 16 2.6 20 2.2 4
77 2.6 89 21 16 3.5 17 3.6 3
78 4.2 80 20 14 3.6 18 3.0 3
79 5.0 97 21 20 5.0 24 2.8 3
80 19.3 94 18 22 4.3 23 3.2 3
86 32.0 96 13 19 2.8 20 1.8 4
87 11.3 100 11 19 2.7 22 0.5 3
89 3.2 91 13 18 2.6 21 1.1 6
90 3.4 87 18 19 3.5 20 2.6 3
91 13.4 96 16 22 3.8 23 2.4 7
92 15.5 93 16 20 3.4 21 2.2 7
93 5.1 97 12 14 2.4 18 1.7 3
94 3.6 52 19 24 4.7 24 2.1 3
Table I----Yield of Nuts and Kernels, and Cracking Quality of Nuts from
132 Sample Trees of Common Black Walnut in the Tennessee Valley (continued)
_________________________________________________________________________
Tree
_____________________
Diameter
at 4-1/2 ______________________________________________________
Sample ft.
number av. yr. 1940 1941 1942 1943 1944 1945 Av. yr.
_________________________________________________________________________
inches pounds pounds pounds pounds pounds pounds pounds
96 16.5 23 31 93 51 29 103 55
97 9.8 2 8 9 7 4 6 6
98 21.3 44 20 66 35 26 4 32
100 27.8 159 272 65 334 6 80 153
101 21.2 0 294 120 206 30 239 148
102 13.1 38 2 44 4 12 3 17
103 7.5 20 15 25 30 9 119 36
104 12.3 40 17 52 17 16 0 24
106 11.4 50 16 66 29 46 66 46
107 13.2 29 0 5 8 0 1 7
108 9.0 34 11 12 25 12 7 17
109 12.6 11 12 30 69 0 14 23
110 14.9 65 104 29 61 54 32 58
111 11.3 8 55 5 65 0 54 31
116 11.8 0 16 6 7 4 9 7
117 17.0 10 285 13 142 116 387 159
118 13.3 3 78 6 170 4 263 87
119 14.6 0 34 148 0 40 145 61
121 17.6 67 9 41 15 0 64 33
129 13.3 13 70 8 157 0 149 66
130 15.3 47 1 50 10 0 24 22
131 16.2 78 1 33 89 0 69 45
132 14.2 6 8 22 10 0 17 10
134 13.3 9 20 11 17 24 3 14
135 14.1 12 55 0 15 0 94 29
136 15.1 7 1 18 14 0 2 7
137 9.4 27 0 38 13 5 28 18
138 14.5 36 18 28 35 69 8 32
139 10.2 14 9 19 64 51 0 26
140 11.1 0 18 62 53 28 34 32
______________________________________________________________________________
Av. Filled nuts Complete crack
Kernel _________________ ________________________
yield First-
bearing In terms crack Crops
yrs. of total Average marketable Kernel tested
number only weight weight kernel weight Kernel Quarters basis
______________________________________________________________________________
pounds percent grams percent grams percent number number
96 9.6 100 12 15 2.1 17 0.7 3
97 0.6 51 11 13 1.7 15 2.0 3
98 2.7 44 18 10 2.4 13 0.4 7
100 31.4 97 22 17 4.6 21 2.8 7
101 31.7 94 25 15 4.8 19 1.5 3
102 3.4 49 18 19 3.6 20 2.5 3
103 5.9 94 19 16 3.7 20 0.9 3
104 4.4 84 15 15 2.5 17 0.8 3
106 6.2 81 18 15 3.1 17 1.4 3
107 2.1 78 13 14 2.1 16 0.7 4
108 3.4 99 16 17 3.4 15 0.9 3
109 5.0 98 14 14 2.6 18 0.6 3
110 9.1 77 23 14 4.8 20 1.1 3
111 7.7 100 15 17 3.0 21 0.6 3
116 1.4 100 15 16 2.7 18 0.7 3
117 32.2 86 29 15 5.7 20 1.5 7
118 15.2 96 19 12 3.3 18 0.2 3
119 12.2 72 20 18 4.0 20 1.6 3
121 7.1 92 16 17 3.0 19 0.7 3
129 14.2 98 16 15 3.0 18 0.8 3
130 4.4 97 13 14 2.2 16 1.3 4
131 10.2 95 19 17 3.8 20 1.7 3
132 2.7 98 17 16 3.5 21 1.0 3
134 1.7 75 16 14 2.6 16 0.7 3
135 3.4 58 20 15 3.3 16 1.5 3
136 1.8 41 10 13 1.7 17 0.1 3
137 2.7 66 15 17 3.0 20 0.7 3
138 2.7 49 16 15 2.6 19 0.6 4
139 8
140 7.6 92 13 19 2.9 22 0.8 3
199 13.3 15 4 2 2 6
200 10.4 18 17 1 1 9
201 13.1 30 28 23 117 50
202 15.1 2 4 14 0 5
203 13.7 13 30 8 21 18
205 22.6 56 34 33 77 50
206 9.3 46 26 39 4 29
207 5.8 1 0 9 1 3
208 10.4 2 8 4 19 8
210 6.6 35 0 15 0 12
211 12.6 2 4 3 1 2
214 13.1 32 11 19 24 22
215 6.9 3 5 6 0 4
216 10.8 0 6 2 5 3
217 19.1 111 12 62 25 48
218 7.1 18 0 1 0 5
219 12.0 5 13 26 14 14
220 10.7 13 0 8 6 7
221 6.4 0 0 0 3 1
222 15.3 29 6 6 7 12
223 19.2 22 3 6 0 8
224 13.9 53 11 16 29 27
225 16.8 16 57 27 48 37
226 15.6 119 26 101 13 65
227 6.6 9 12 0 33 14
228 7.3 4 9 0 2 4
231 18.4 74 41 0 184 75
232 21.1 47 0 0 180 57
236 22.3 8 204 0 120 83
237 20.3 121 29 86 95 83
240 6.6 5 7 3 13 7
241 13.0 50 24 44 2 30
242 6.4 11 8 10 1 8
243 22.0 82 0 13 11 26
246 21.1 93 220 52 216 145
247 19.1 2 57 17 1 21
199 1.8 49 19 22 4.8 25 3.0 4
200 1.7 24 17 16 3.3 19 2.0 3
201 10.9 100 17 19 3.8 22 2.2 3
202 0.4 46 21 14 4.1 20 1.0 3
203 4.3 97 18 23 4.4 25 3.1 3
205 6.4 19 11 22 2.6 23 4.0 1
206 4.2 98 19 12 2.7 15 2.2 3
207 0.7 21 17 15 2.8 16 2.0 2
208 1.1 66 16 22 3.8 24 2.4 3
210 4.8 98 17 14 3.2 19 0.7 3
211 0.3 83 11 11 1.6 15 0.2 3
214 3.0 87 18 16 3.1 17 2.7 3
215 0.9 100 13 18 2.7 20 0.7 3
216 0.7 97 11 13 1.7 16 0.6 4
217 12.1 93 18 21 4.4 25 0.8 3
218 1.7 100 18 17 3.0 17 2.6 2
219 2.5 94 11 17 2.0 18 0.8 3
220 0.8 61 20 13 3.2 16 1.9 3
221 0.4 53 16 20 3.4 21 3.2 2
222 1.3 72 16 16 3.0 18 1.9 3
223 0.8 55 12 19 2.6 20 0.5 3
224 4.9 93 17 16 3.5 20 1.1 3
225 7.8 94 15 18 3.4 22 1.0 3
226 9.8 96 12 12 1.9 16 0.2 3
227 4.2 99 16 19 3.6 23 0.7 3
228 1.1 99 15 21 3.3 22 2.3 3
231 7.3 52 10 17 2.3 19 1.1 3
232 26.6 98 19 17 4.5 24 2.0 3
236 10.5 26 15 17 3.0 19 0.5 2
237 16.1 100 18 14 3.5 19 1.5 3
240 1.2 100 14 15 2.5 17 0.9 3
241 4.6 96 14 15 2.3 16 1.2 3
242 1.4 98 13 17 2.5 20 0.7 3
243 4.9 98 14 12 2.0 14 1.3 3
246 29.6 98 14 16 2.9 21 0.7 3
247 1.2 23 15 12 1.7 15 0.2 3
Results of cracking tests show that, in general, cracking quality of nut
samples from the trees in this study is poor. When cracked, the kernels
crumble badly, making extraction difficult and quarter recovery low.
Variation in cracking quality can be seen by studying the values in
Table 1. Nuts from trees 28 and 136 were extremely small, averaging 9
and 10 grams, respectively. Nuts from trees 61 and 98 had generally poor
characteristics. Trees bearing walnuts of better-than-average quality
are trees 5 and 18 with high total kernel per cent, and trees 8, 16, and
59 with high nut weight and an unusually high kernel weight. Other
trees, of interest as exceptional bearers, include tree 101 with large
nut weight, and tree 117 with both exceptional nut and kernel weight.
The outstanding tree in the study from the standpoint of cracking
quality of the nuts is tree 13, which has exhibited those
characteristics of thinness of shell and high kernel content sought for
in improved varieties. This black walnut selection is being propagated
at the Norris Nursery under the appropriate name of Norris.[14]
[Footnote 14: Kline, L. V. A method of evaluating the nuts of black
walnut varieties. Proc. Amer. Soc. Hort. Sci. 41:136-144. 1942.]
Results from this study on the common black walnut have application in
the evaluation of the relative yield and nut quality of improved
selections suitable for use in the Tennessee Valley. This summary should
also prove of value to other workers dealing with black walnut in other
regions. It provides a basis for comparison, brings out the
possibilities for making selections, and emphasizes the importance of
nut production from improved varieties.