Some Results with Filbert Breeding at Geneva, N.Y.[6]

Some Results with Filbert Breeding at Geneva, N.Y.[6]

GEORGE L. SLATE New York (Geneva) Agricultural Experiment Station

This paper reports the results of attempts to improve filberts by hybridization at the Experiment Station at Geneva, N. Y. The filbert project was started at Geneva in the spring of 1925 when a collection of varieties from American sources was established. In later years additional varieties from European and other sources were added until about 120 were under test. As soon as the varieties had fruited for several years it became evident that many of them were inferior and not adapted to New York conditions. A few exhibited considerable merit and the range of characteristics in the different varieties indicated that it might be worth while to start a filbert breeding project with the object of combining the desirable characteristics of the better sorts.

It was decided first to cross Rush, a selected form of Corylus americana, with the best varieties of Corylus Avellana, Rush contributing the hardiness of the native hazel, possible resistance to filbert blight, and the hybrid vigor that sometimes results from the crossing of two species. The European filberts were expected to furnish large-sized nuts as well as dessert and cracking quality.

The first crosses were made in 1930 when two trees of the Rush variety growing on Dr. MacDaniels' place in Ithaca were pollinated with pollen of several varieties of Corylus Avellana that was brought from Geneva. Additional crosses were made at Ithaca in 1931 and 1933. In 1932 the pollinations were made at Geneva, using a Barcelona tree covered with a tightly woven cloth. No pollinations have been made since 1933.

In the spring of 1932, 535 seedlings were received from Willard G. Bixby, of Baldwin, Long Island, N. Y., which had resulted from crosses made by C. A. Reed of the United States Department of Agriculture, at Baldwin. Including these U.S.D.A. seedlings and those resulting from the breeding work at Geneva, 1,999 seedlings have fruited.

The nuts from these crosses were stratified in sand in a cold frame, dug up, and planted in the greenhouse in early March. After one transplanting they were moved to the nursery to grow for two years, when they were moved to the seedling orchard. The nuts from one year's crosses were planted directly in the nursery but germination was low due to drought.

The seedlings were spaced 10 x 5 feet in the orchard. This spacing was satisfactory if the trees came into bearing the fourth year, but if unfavorable weather eliminated the first or second crops the trees became too crowded to permit satisfactory fruiting. Usually, however, the trees fruited sufficiently to make it possible to evaluate them and remove the inferior trees so that the better seedlings would have enough room to remain for several additional crops.

During the first few years the orchard was clean cultivated until cover crops were sown in August. In later years the orchards were not cultivated but nitrogen fertilization was substituted. Satisfactory growth was maintained, but the grass and weeds made harvesting more difficult. No pruning was done except at planting time as the seedlings were all evaluated before pruning was needed. Suckers were removed around the young trees, but as they became older this was not done and some of the plants now have several stems.

Evaluating the Seedlings

The nuts were harvested in the fall after they had dropped, or, with the later maturing seedlings and those which tended to cling to the tree, they were harvested by picking or shaking them from the tree. As soon as practicable the nuts were husked and the crop of each tree weighed and recorded. Samples of nuts of every seedling fruiting were placed on paper plates, each population being by itself, and eight or ten nuts of each sample were cracked and left on the plate. The seedlings were then divided into three classes, those that were obviously good, those that were poor, and an intermediate class that received further attention. The poor seedlings were marked for discard and if so marked for two or three years they were pulled out.

The good seedlings were then examined more carefully and sorted into three groups, as follows:

1. Those that were outstanding in both nut and tree characters.

2. Those that were good enough to propagate for a second test, but not equal to the best.

3. Seedlings good enough to keep for further observation. These were usually good in one or more characteristics but deficient or doubtful in one important feature. If upon further testing these third group plants proved to be outstandingly productive or hardy they were given a higher rating.

In examining the nuts, emphasis was placed on size and color of the nut, the large, bright brown nuts being considered more desirable than the smaller, duller colored, pubescent nuts. The amount of space between the shell and the kernel was important. If the kernel fitted tightly it was easily broken or chipped in cracking the nut. Thickness of shell was of minor importance as only a few were thick enough to make cracking difficult.

The kernel characters were of most importance since the kernel is the reason for producing the nut. The kernel must be plump, smooth, light brown in color, and free of the superfluous pellicle, or fibrous material that is characteristic of the Barcelona kernels. Generally, seedlings with Rush as one parent had very little of this superfluous fibrous material and the best of them were much superior to Barcelona in appearance and dessert quality. Flavor received less consideration since most of the seedlings were reasonably good in that respect.

Given a good kernel, and there were many of them, it became necessary to rely upon other characteristics to eliminate the less desirable of these seedlings. It was here that the records of yields and catkin hardiness were valuable. After several years it became evident that certain seedlings were consistently high yielding while others were low yielding. Hardiness of catkin also varied greatly and rather consistently from year to year. Weather conditions influenced catkin killing greatly. Catkin hardiness is important since the pollen is necessary for nut production and must be present in abundance as its movement in the orchard is subject to the vagaries of the wind, and only a small percentage of that in the air ever comes in contact with the stigmas of the other varieties.

It is the purpose of this paper to indicate the value, insofar as it may be estimated from the available data, of the different varietal crosses in obtaining desirable filbert hybrids. Table 1 contains a list of crosses made, the number of seedlings raised, and the percentage of these which were of sufficient merit to be retained for further study. The percentage of seedlings propagated indicates even more definitely which crosses are of the greatest value in producing superior seedlings as only the outstanding seedlings were propagated for a second test. Selections included in Table 1 are there by virtue of their all-around merit.

Crosses between Rush and Littlepage and Rush and Winkler produced nothing of value. The populations were small, but other equally small populations from other crosses produced seedlings of value. The inter-crossing of selections of Corylus americana does not appear to be a promising line of attack in filbert breeding where hybrids with C. Avellana will thrive.

Rush and Barcelona were each used as seed parents in crosses with the same eight varieties. In the crosses involving Rush 1,232 seedlings were produced and of these 39, or 3.2%, were good enough to propagate. Of the 306 seedlings raised from the same varieties combined with Barcelona only 4, or 1.3% were worth propagating. None of these Barcelona seedlings are among the best. Under the conditions of the experiment it would seem that Rush is much superior to Barcelona as a parent in crosses with varieties of Corylus Avellana.

The cross between Kentish Cob and Cosford failed to produce any seedlings of outstanding merit.

In considering the productiveness and hardiness of the catkins of the seedlings resulting from the different crosses the data have been assembled in Tables 2 to 5, each table containing the summarized records for different plantings. These plantings were started at different times and the records are not directly comparable as they are for different years and varying lengths of time. In Table 1 the total number of seedlings is given, but in Table 2 to 5 only the data for the selections are used. Records for the selections are available for several years, whereas the inferior seedlings were discarded and limited data only are available. Furthermore, the filbert breeder is interested primarily in the worthwhile material that may be taken from populations of known parentage.

Assuming that we have a fairly good nut productiveness is the most important characteristic in a filbert. If the plant is productive it must of necessity be reasonably vigorous and hardy. For that reason much emphasis has been placed on productiveness in the final evaluation of the selections.

The selections in Table 2 are from the U.S.D.A. Bixby plants which were the first to fruit at Geneva. Considerable variation in productiveness is evident in the different populations. Rush x Kentish Cob and Rush x White Aveline selections were only about half as productive on the average as Rush x Barcelona, Bollwiller, Red Lambert, and Daviana. Rush x Italian Red also failed to produce high-yielding selections. In a later planting in the same orchard, as shown in Table 3, the Rush x Kentish Cob selections performed no better, the Rush x Red Lambert selections outyielding them by a substantial margin. The Barcelona x Italian Red selections were very low yielding.

In orchard 22, as shown in Table 4, where Rush and Barcelona are crossed with the same varieties, the resulting selections from the Rush crosses are about one third more productive if mean yields are considered, or one-half more productive if only highest yielding selections are considered than with the Barcelona crosses. Cosford has been outstanding in transmitting productiveness in crosses with Rush, Italian Red, and Nottingham. Rush x Kentish Cob selections in this orchard as in the other planting, were only about one half as productive on the average. In the crosses with Barcelona the combination with Medium Long, Red Lambert, and Italian Red were considerably more productive than crosses with Purple Aveline, Halle, Daviana, and Bollwiller.

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.

CrossNumber of Seedlings FruitedNumber RetainedPercentage RetainedNumber PropagatedPercentage Propagated

Rush x Kentish Cob (Du Chilly4306314112

Rush x Cosford4475212112

Rush x Bollwiller165181163

Rush x Italian Red118171621

Rush x Red Lambert361028616

Rush x Daviana13215215

Rush x Purple Aveline1232518

Rush x White Lambert110000

Rush x Barcelona119201632

Rush x White Aveline54101835

Rush x Imperial deTrebizond2452114

Rush x Nottingham2373028

Rush x Brixnut822500

Rush x Littlepage120000

Rush x Winkler60000

Barcelona x Kentish Cob (Du Chilly)42215037

Barcelona x Cosford57274812

Barcelona x Bollwiller1121800

Barcelona x Italian Red6691300

Barcelona x Red Lambert41122900

Barcelona x Daviana2152400

Barcelona x Purple Aveline2583200

Barcelona x White Lambert431200

Barcelona x Medium Long45163500

Barcelona x Early Globe780000

Barcelona x Halle1265000

Barcelona x Red Aveline911100

Kentish Cob (Du Chilly) x Cosford35226300

Total197034017522.6

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 SelectionsMean Yield per Selection in OuncesHighest Yield per Selection in OuncesMean Percentage Catkins Winter Killed per SelectionLowest Percentage Catkins Winter Killed

Cross

Rush x Bollwiller1881143214

Bush x Kentish Cob (Du Chilly) 1238117363

Rush x White Aveline94473420

Rush x Barcelona694147268

Rush x Imperial de Trebizond5811002810

Rush x Italian Red37980153

Rush x Red Lambert38811673

Rush x Daviana2821103326

Rush x Purple Maxima137371717

Table 3. Yields and winter injury of filbert catkins, Orchard 16, 1937-41 inclusive.

No. of SelectionsMean Yield per Selection in OuncesHighest Yield per Selection in OuncesMean Percentage Catkins Winter Killed per SelectionLowest Percentage of Catkins Winter Killed

Cross

Rush x Kentish Cob (Du Chilly)2638102685

Rush x Barcelona1452899038

Rush x Red Lambert567117125

Barcelona x Italian Red318208373

Table 4. Filbert selections. Orchard 22. Yields 1939, 1940, 1941, 1942, 1944, 1945 and 1946. Catkin injury records 1939-42, inclusive.

No. of SelectionsMean Yield per Selection in OuncesHighest Yield per Selection in OuncesMean Percentage Catkins Winter Killed per SelectionLowest Percentage of Catkins Winter Killed

Cross

Rush x Cosford26129229420

Rush x Kentish Cob (Du Chilly)25681857013

Rush x Nottingham7961803114

Rush x Italian Red31141814530

Rush x Purple Aveline31142404225

Rush x Red Lambert290127218

Rush x Brixnut249516258

Barcelona x Cosford27901386232

Barcelona x Kentish Cob (Du Chilly)21691266925

Barcelona x Medium Long16932578371

Barcelona x Red Lambert12831475213

Barcelona x Purple Aveline850737855

Barcelona x Italian Red6841339081

Barcelona x Halle652795223

Barcelona x Daviana553756759

Barcelona x Bollwiller266946258

Barcelona x Red Aveline191915656

Barcelona x White Lambert110310355

Kentish Cob (Du Chilly) x Cosford22621516433

Table 5. Filbert selections. Orchard 8. Yields 1940, 1941, 1942 and 1944. Catkin injury records 1940, 1941 and 1942.

No. of SelectionsMean Yield per Selection in OuncesHighest Yield per Selection in OuncesMean Percentage Catkins Winter Killed per SelectionLowest Percentage of Catkins Winter Killed

Cross

Rush x Cosford262547302

Rush x Italian Red112539270

Discussion after Mr. Slate's paper—

MacDaniels: "Of the 1999 seedlings tested at Geneva, 52 are being carried on for further observations. Prof. Slate is doing a fine work."

J. R. Smith: "I want to express my appreciation of the work Prof. Slate is doing. To care for 1999 seedlings and keep the performance records is a big job and just the kind of thing on which progress depends."