Factors influencing the breeding of agricultural crops in the Netherlands

The writer draws attention to some factors influencing the breeding of agricultural crops in the Netherlands. The mutual influence of breeding new varieties, research on varieties, seed production, agricultural production and export is explained.In the Netherlands, farmers on average purchase approved seed potatoes once in three years, which equals the frequency of replacement of the seed of rye. On the area covered by wheat five-eighths is sown with approved seed and of peas and oats, one-half. In the case of sugar beet, fodder beet and some other crops (including vegetables) 100% original seed is used.The writer draws attention in particular to the reasons why there is a continuous need for new seed and seed potatoes. As causes are mentioned: 1. the fact that a farmer did not grow a particular crop in the previous year; 2. that he had difficulties with the seed production of a given variety or the variety deteriorated owing to impurity, diseases or admixtures; 3. the wish to choose a new variety of better yielding capacity or other favourable properties; 4. purchase of original seed of a variety in demand for increase to once grown original seed or purchase of first rate starting material from the clonal selection farms for growing seed potatoes of a variety in demand.

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Samenvatting Schrijver vestgt de aandacht op de invloedssferen van de veredeling van landbouwgewassen in Nederland. Met enige voorbeelden wordt de invloed van het kweken van nieuwe rassen op het rassenonderzoek, de zaaizaad- en pootgoedteelt, de landbouwproduktie en de export toegelicht.In Nederland schaft de boer gemiddeld eens in de drie jaar goedgekeurd pootgoed van aardappelen aan, terwijl de frequentie van vernieuwing van zaaizaad van rogge daaraan gelijk is. Bij tarwe wordt voor 5/8 van het areaal goedgekeurd zaaizaad gebruikt, bij erwten en haver voor de helft van het areaal. Voor suikerbieten, voederbieten en enige andere gewassen wordt 100% origineel zaaizaad gebruikt.Schrijver vestigt in het bijzonder de aandacht op de oorzaken waardoor er een voortdurende behoefte aan nieuw zaaizaad en pootgoed is. Als oorzaken worden genoemd dat de boer het gewas in het voorgaande jaar niet verbouwde, tegenslag met eigen zaaizaad- of pootgoedwinning van een bepaald ras of achteruitgang van dat ras door rasonzuiverheid, ziekten, vermenging, de wens een nieuw ras te kiezen met hoger opbrengstvermogen of andere gunstige eigenschappen, aanschaf van origineel zaaizaad van een gevraagd ras voor vermeerdering tot le nabouw, aanschaf van hoogwaardig uitgangsmateriaal voor de teelt van pootaardappelen.

     

Some data and figures on potato breeding in the Netherlands

Summary The rapid growth of the number of potato breeders in the Netherlands was favourably influenced by a wide spread interest for all problems concerned with potatoes, by financial support and advice.In 1954, the number of potato breeders was 193; 46 of them can be considered professional breeders, while of 20 breeders one or more varieties figure in the Dutch List of Varieties 1954.The creation of the Foundation for Agricultural Plant Breeding resulted in the enhancement of the level of potato breeding and the increase of the number of potato seedlings raised every year.     

Some remarks on carrot breeding (Daucus carota sativus Hoffm.)

Carrot breeding in the past 150 years has resulted in varieties with high yield, a short growing period, and excellent root colour. Recently, hybrid varieties have demonstrated good uniformity of roots, a quality accepted by most consumers. By contrast, only a few resistant varieties (mainly open-pollinated varieties) are offered by seed companies, most being resistant to Alternaria. Hybrid breeding offers a chance of combining good uniformity and different sources of resistance. Efforts in future breeding should concentrate on the improvement of health and the development of genotypes suitable for cultivation in suboptimal climates and regions, as well as for special applications.     

Oat breeding in the Netherlands

Summary While towards the turn of the century the German yellow oat Probsteier had spread considerably in the Netherlands a shift occurred after about 1910 in favour of Svalöf varieties. First Victory spread, later other varieties followed. Dutch agriculture has derived much benefit from these varieties.However, oat breeding in the Netherlands developed also. In the course of years the breederMansholt produced several varieties, which together occupied about 20% of the area under oats. To the breederP. J. Hijlkema belongs the honour of creating the variety Marne, which could successfully compete with the Svalöf varieties.In 1953 Mansholt's varieties occupied 2% of the area under oats; Hijlkema's varieties 63%; the variety of the Central Bureau 5% and Black President 1%. That means that in 1953 home-bred varieties occupied 71% of the land under oats.The changes that have occurred in the varietal range are shown in Fig. 1.Some of the Dutch varieties are also appreciated abroad.

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Samenvatting Nadat in het laatst van de vorige eeuw de Duitse Probsteier gele haver zich sterk had verbreid in Nederland, is sedert ±1910 een verschuiving ingetreden in de richting van de Svalöf-rassen. De Zegehaver b.v. kreeg een zeer grote verbreiding; daarna volgden andere. De Nederlandse landbouw heeft dankbaar gebruik gemaakt van de buitenlandse haverrassen.Toch heeft de haververedeling in Nederland niet stilgestaan. In de loop der jaren zijn verschillende Mansholt-rassen gekweekt, die gedurende een aantal jaren tezamen ongeveer 20 % innamen van de in Nederland met haver beteelde oppervlakte.Aan de kwekerP. J. Hijlkema komt de eer toe, dat hij er in slaagde de Marne haver te kweken, die in staat was de concurrentie tegen de buitenlandse rassen op te nemen.Het Nederlandse haverareaal is thans voor meer dan de helft gebaseerd op Nederlandse rassen en verschillende daarvan vinden in het buitenland waardering. Het percentage van de Mansholt-rassen bedroeg in 1952 2 %, van de Hijlkema-rassen 63 %, van het C B-ras 5 % en van de Zwarte President 1 %; in totaal was dus 71 % van het Nederlandse haverareaal in 1953 bezet met Nederlandse rassen.De verschuiving in het rassensortiment van 1933 af is aangegeven in fig. 1.

     

Wheat breeding in the Netherlands

Summary In 1886L. Broekema (Wageningen) laid the foundation for wheat breeding in the Netherlands. He succeeded in breeding Wilhelmina wheat (1901) and later Juliana, among other varieties.About the same timeJ. H. Mansholt (Westpolder) andDr. O. Pitsch (Wageningen) started their wheat breeding programmes.It should be stated that these pioneers practised line selection in hybrid populations from the very beginning.Among the other wheat breeders mention should be made ofDr. R. J. Mansholt (Westpolder) who, among other varieties, developed Wilobo and Lovink winter wheat and Van Hoek and Mansholt Witte spring wheat. The Breeding Station C.B. (Hoofddorp) bred the variety Staring,M. Rademakers (Bant, N.E. Polder) Mado, the Seed Company Wiersum (Groningen) Titan, Demeter and Tavero.It appears from the varietal ranges (Figs. 6 and 7) that at present foreign varieties are widely grown. However, wheat breeding in the Netherlands has not fallen asleep; at some breeding establishments large-scale breeding programmes are under way.     

Horticultural plant breeding in the Netherlands

Summary Since the 16th century horticulture developed relatively early and rapidly in the Netherlands, and in the growing centres of vegetables and ornamentals a great number of highly improved varieties were produced by professional growers. A number of new fruit varieties was raised by professional men or by amateurs.During the last ten or twenty years science is being incorporated more and more into horticultural plant breeding. In ornamentals and vegetables this takes the form of cooperation between professional breeders and scientific institutions, in fruit the breeding work is mainly done by institutions.     

Winter barley breeding in the Netherlands

Summary Various Dutch breeders have devoted themselves to winter barley breeding; the local variety Groningen Winter Barley used always to be the foundation material for breeding work. In the course of years 8 new varieties have been derived from it by line selection which demonstrates clearly the degree of variation.The varietal range (fig. 1) shows the peculiarity that the leading variety Vindicat has almost completely been superseded by Urania within some years. If ever, the slogan the Dutch farmer readily accepts new varieties applies here.Its sister variety Vinesco makes a favourable impression.The varieties of winter barley are now for 97 percent based on homebred material.     

The breeding of peas in the Netherlands

Summary The varietal assortment of Dutch round blue pea varieties has changed considerably. At the beginning of this century their cultivation was based entirely on the varieties bred by Dr R. J. Mansholt at Westpolder (Gr.). Since 1937 the Unica pea produced by P. J. Hijlkema, Mensingeweer (Gr.), has gained ground. Mansholt's G.E.K. and Unica were dominant for many years, and were also used abroad.A remarkable change in the varietal assortment of the round blue peas occurred since the appearance of varieties less susceptible to the Fusarium solani foot disease. Particularly the Rondo C.B. pea of the Plant Breeding Station C.B. (Dir.: Ir C. Koopman) at Hoofddorp has become widely grown (Fig. 2).In addition, it was this same station that succeeded in breeding a variety entirely resistant to fusarium wilt.It is clear that, in the course of the past few years, new varieties have been bred by the breeders. The new varieties excelled the established ones in one or more respects.Some varieties were widely distributed, others were discarded by the breeders after a couple of years, or (since 1924, the year when the first List of Varieties appeared) written off the List.Widely cultivated varieties had to retire in their turn when better ones came on the market.Even at present time Dutch plant breeders are working hard to improve the yield, quality and reliability of peas.     

Notes on the history of bulb breeding in the Netherlands

Summary In the early days of bulb breeding, plants were selected for their beauty-rarely a joy for ever, since fashion changed and new varieties supplanted their ancestors. Beauty has remained the first requirement to the present day. However, physiological characters such as easy propagation, good growth, and suitability for early forcing, are almost as important at present. The merits of a plant for garden decoration take third place.The number of varieties that can meet these requirements is very small; but since the demand is for the best in great quantities, this small group accounts for the greater proportion of all bulbs grown, as demonstrated by the statistical data. It will be very difficult to surpass these varieties, or even to make additions to this group.In hyacinths and daffodils it is even more difficult to develop breeding schemes, as the leading varieties are mostly heteroploids and polyploids, respectively. Here a breeder's intuition is needed above all things to bring us better varieties.     

List of breeders of agricultural crops in the Netherlands

The author gives a survey of the 71 Netherlands plant breeding establishments mentioned in the List of Varieties of Field Crops while also the research workers engaged in breeding agricultural crops have been included.The Plant Breeder's Decree 1941 stimulated plant breeding in the Netherlands so that the number of plant breeders increased considerably. The work of the existing plant breeding establishments was intensified accordingly.On a map of the Netherlands the location of these breeding establishments has been indicated.The article concludes with reflections on the plant breeding establishments in the Netherlands.     

Some remarks on honeycomb selection

Summary Up to now the only experiences in favour of the method of honeycomb selection were reported by the spiritual father of the method, i.e., Fasoulas. Three other reports presented very moderate results. Possible causes for these contrasting results are discussed. Fasoulas' preference for growing the plants in the selection field in absence of competition is in conflict with the conditions in commercial crops where intragenotypic competition occurs. This preference is considered in comparison with the more popular preference for growing the plants in the selection field in presence of intergenotypic competition, which in turn also deviates from the conditions in a commercial field. It is suggested that at some degree of interplant competition the highest response to honeycomb selection will be obtained. Further, it is explained why the average of the phenotypic values of the six neighbours of a central plant may be an unreliable measure for the growing conditions for the central plant.     

The breeding of scab-resistant frame cucumbers in the Netherlands

Summary Scab caused by the fungus Cladosporium cucumerinum, may cause serious damage to frame cucumbers. Bulbosan (trichlorotrinitrobenzene) is an effective chemical means of control. Between 1945 and 1954 this German fungicide could not be supplied, and, as a result, the need for resistant varieties became very great.Before 1920 scab-resistance in pickling cucumbers was already known to Dutch growers. Selection started around 1920 on the initiative of W. G. v. d. Kroft and resulted in scab-resistant pickling cucumbers of which Baarlose Nietplekker VI is still widely grown. In 1948 G. W. v. d. Helm (Exp. Garden at Sloten) started breeding a scab-resistant yellow slicing cucumber destined for gardeners in the neigh-bourhood of Amsterdam. The resistant variety Highmoor was used as one parent. In 1954 the yellow variety Vios and the white variety Mabro were introduced. In 1952 G. W. v. d. Helm at the Exp. Garden Sloten, and J. M. Andeweg at the Institute of Horticultural Plant Breeding, Wageningen, simultaneously started breeding green scab-resistant frame cucumbers, using Highmoor as the resistant parent. In 1955 the experimental garden at Sloten introduced the scab-resistant green slicing cucumbers Amato and Proso, while in 1956 the Institute of Horticultural Plant Breeding introduced the scab-resistant green slicing cucumber Esvier. In 1953 seed of 2 first-backcross populations was supplied by the Institute to seed growers. At present intensive breeding for scab-resistance is also being carried out by a number of Dutch seed growers.Scab-resistance depends on one dominant gene; and young plants can readily be tested for resistance. Consequently a backcross scheme can easily be carried out. Rapid breeding is possible because at least 2 cultures can be carried out yearly. If necessary, cuttings of promising plants can be taken. Before and after artificial pollination the flowers can be tied up with raffia. It is simpler, however, to pinch the flowers with a special stainless clip as originally used for grafting cucumbers.The uniform fruit colour of the Dutch green frame slicing cucumbers is a recessive character; the fruit length of the Dutch varieties is dominant.     

Strawberry breeding for red core resistance in the Netherlands

Summary The appearance, a few years ago, of red core disease (Phytophthora fragariae Hickman) in strawberry crops in the Netherlands, has made it desirable to grow resistant varieties and to include red core resistance in our breeding programme.An account is given of the results of some field trials in 1968–1970 on a very wet, sandy soil, infected with P. fragariae, involving varieties, selections and seedling progenies.In both years distinct differences in resistance and susceptibility occurred between varieties and selections. The seedling progenies gave significant differences in percentages of surviving, healthy plants.Samenvatting Het optreden van rood wortelrot (Phytophthora fragariae Hickman) enkele jaren geleden in de aardbeiteelt in Nederland, heeft het gewenst gemaakt resistente rassen te telen en resistentie in ons veredelingsprogramma op te nemen.In dit artikel worden de resultaten vermeld van enkele veldproeven met rassen, selecties en zaailingpopulaties in de jaren 1968–69 en 1969–70 op een zeer natte, met P. fragariae besmette zandgrond.In beide jaren traden duidelijke verschillen in vatbaarheid op tussen de rassen en selecties. De zaailingpopulaties vertoonden eveneens duidelijke verschillen in de percentages overlevende, gezonde planten.     

Conditions favouring doubled haploid breeding over conventional breeding of self-fertilizing crops

Summary Monte Carlo computer simulation was used to investigate the conditions favouring doubled haploid breeding over conventional breeding of self-fertilizing crops. Two different systems of doubled haploid breeding and three systems of conventional breeding were compared for two criterion parameters, i.e., the probability of obtaining desirable genotypes and the expected genetic advance of selected lines. It was inferred that the efficiency of production of haploid and doubled haploid plants primarily determines the success of the doubled haploid breeding method. In doubled haploid breeding, about 1/5, hopefully 1/2 as many test plants need to be raised as in conventional breeding to achieve the same level of success. With this condition begin satisfied, the doubled haploid breeding method can efficiently be used when one or more of the following conditions are met: (i) a relatively small number of loci, presumably ten of less, is involved with the breeding objective concerned, (ii) desirable alleles are recessive to undesirable ones at most, if not all, of the segregating loci, and (iii) the genes are not strongly linked. It was confirmed that the doubling of haploids can better be applied to selected F₂ plants rather than to F₁ plants.