The Kentish Cob x Cosford cross was less productive than most of the other combinations made. Kentish Cob definitely appears to transmit unproductiveness when crossed with Rush, Barcelona, and Cosford.
In orchard 8 as shown in Table 5, the trees soon became very crowded as the discards were not removed and the yield records were less reliable than in the other plantings.
Winterkilling of catkins were recorded on the selections for several years. In early April the percentage of winter-killed catkins was recorded by estimate. Tables 2 to 5 contain the mean of these estimates and a considerable variation in catkin hardiness in the different populations is evident. Red Lambert, which had the hardiest catkins of any variety of C. Avellana tried at Geneva, produced a higher proportion of catkin-hardy seedlings than any other variety. Cosford was fairly good in this respect and in orchard 16 Bollwiller, Italian Red, and Barcelona when crossed with Rush produced selections with moderately hardy catkins.
Winter injury of catkins was nearly always very high in crosses between varieties of Corylus Avellana.
Of the 1,970 seedlings included in Table 1, 340 or 17%, were retained for further observation and of these, 52, or 2.6%, were considered good enough to propagate for a more extensive test. Of these 52 a few thus far have been outstanding when compared with the others. Possibly the best and most productive selection is No. 1265, Rush x Purple Aveline, that is the heaviest yielding of all and the nuts are also among the best, being of medium size, plump, and free from fiber. This seedling is far superior to any others from the same cross. Nos. 1408 and 1467, both selected from a Rush x Cosford population, are close seconds to No. 1265. In the Rush x Cosford population are several others nearly as good, the general level of merit in this combination being fairly high. Farther down the list, but still among the best, are No. 110 Rush x Kentish Cob, and No. 157, Rush x Barcelona. Filbert breeders working under similar conditions would probably find it worthwhile to make these crosses and also to produce more seedlings from Rush x Red Lambert than were raised at Geneva.
No crosses have been made at Geneva in recent years, but all of the nuts from the selections, sometimes several hundred pounds a year, have been planted by the Soil Conservation Service and the resulting seedlings planted in various parts of the country. Undoubtedly, if these could be examined when in fruit, some worthwhile selections could be made. Those in New York State will probably be worked over during the next few years.
Table 1. Results from filbert crosses.
| Cross | Number of Seedlings Fruited | Number Retained | Percentage Retained | Number Propagated | Percentage Propagated |
|---|---|---|---|---|---|
| Rush x Kentish Cob (Du Chilly | 430 | 63 | 14 | 11 | 2 |
| Rush x Cosford | 447 | 52 | 12 | 11 | 2 |
| Rush x Bollwiller | 165 | 18 | 11 | 6 | 3 |
| Rush x Italian Red | 118 | 17 | 16 | 2 | 1 |
| Rush x Red Lambert | 36 | 10 | 28 | 6 | 16 |
| Rush x Daviana | 13 | 2 | 15 | 2 | 15 |
| Rush x Purple Aveline | 12 | 3 | 25 | 1 | 8 |
| Rush x White Lambert | 11 | 0 | 0 | 0 | 0 |
| Rush x Barcelona | 119 | 20 | 16 | 3 | 2 |
| Rush x White Aveline | 54 | 10 | 18 | 3 | 5 |
| Rush x Imperial deTrebizond | 24 | 5 | 21 | 1 | 4 |
| Rush x Nottingham | 23 | 7 | 30 | 2 | 8 |
| Rush x Brixnut | 8 | 2 | 25 | 0 | 0 |
| Rush x Littlepage | 12 | 0 | 0 | 0 | 0 |
| Rush x Winkler | 6 | 0 | 0 | 0 | 0 |
| Barcelona x Kentish Cob (Du Chilly) | 42 | 21 | 50 | 3 | 7 |
| Barcelona x Cosford | 57 | 27 | 48 | 1 | 2 |
| Barcelona x Bollwiller | 11 | 2 | 18 | 0 | 0 |
| Barcelona x Italian Red | 66 | 9 | 13 | 0 | 0 |
| Barcelona x Red Lambert | 41 | 12 | 29 | 0 | 0 |
| Barcelona x Daviana | 21 | 5 | 24 | 0 | 0 |
| Barcelona x Purple Aveline | 25 | 8 | 32 | 0 | 0 |
| Barcelona x White Lambert | 43 | 1 | 2 | 0 | 0 |
| Barcelona x Medium Long | 45 | 16 | 35 | 0 | 0 |
| Barcelona x Early Globe | 78 | 0 | 0 | 0 | 0 |
| Barcelona x Halle | 12 | 6 | 50 | 0 | 0 |
| Barcelona x Red Aveline | 9 | 1 | 11 | 0 | 0 |
| Kentish Cob (Du Chilly) x Cosford | 35 | 22 | 63 | 0 | 0 |
| Total | 1970 | 340 | 17 | 52 | 2.6 |
Table 2. Yields and winterkilling of filbert catkins, Orchard 16, 1935 1937, 1938 and 1939. Yields are 4 year total. Catkin injury is 5 year mean
| Number of Selections | Mean Yield per Selection in Ounces | Highest Yield per Selection in Ounces | Mean Percentage Catkins Winter Killed per Selection | Lowest Percentage Catkins Winter Killed | ||
|---|---|---|---|---|---|---|
| Cross | ||||||
| Rush x Bollwiller | 18 | 81 | 143 | 21 | 4 | |
| Bush x Kentish Cob (Du Chilly) 12 | 38 | 117 | 36 | 3 | ||
| Rush x White Aveline | 9 | 44 | 73 | 42 | 0 | |
| Rush x Barcelona | 6 | 94 | 147 | 26 | 8 | |
| Rush x Imperial de Trebizond | 5 | 81 | 100 | 28 | 10 | |
| Rush x Italian Red | 3 | 79 | 80 | 15 | 3 | |
| Rush x Red Lambert | 3 | 88 | 116 | 7 | 3 | |
| Rush x Daviana | 2 | 82 | 110 | 33 | 26 | |
| Rush x Purple Maxima | 1 | 37 | 37 | 17 | 17 | |