Tobacco breeding of new tobacco cultivars with improved quality and resistance to diseases by means of conventional, biotechnology and cytogenetics-based methods

With the agricultural institutes in Pulawy, breeding of tobacco varieties has been a tradition for nearly a century. Located very close to the heartland of Poland's tobacco production, IUNG-PIB and its predecessors were very actively engaged in giving scientific support to the community of tobacco farmers, providing them with expert advice on many aspects of tobacco farming but also giving them new varieties. In the sixties and in the seventies of the last century tobacco breeding became one of the trademarks of this institute, as new disease-resistant varieties developed here saved tobacco in Poland from being annihilated by onslaughts of devastating plagues such as PVY and blue mould. They also helped tobacco production in Poland grow into a flourishing enterprise with more than 50000 hectares of land under tobacco and an annual output of ca. 100000 tons of cured tobacco leaves, values reached at the peak of tobacco production in Poland in the late seventies and early eighties.

At present, in the wake of economic changes and incessant campaigns against tobacco, the production of this crop in Poland has scaled down considerably (to ca. 17000 ha) but it still remains a viable option, frequently the only viable option, for many Polish farmers. Surprisingly enough, tobacco in Poland has suffered less than in many other European countries, otherwise much better naturally suited to grow it. Indeed, in these times of adversities Poland, the northern-most tobacco-growing country, not only did not disappear from the map of tobacco production but actually became the third-largest tobacco producer in Europe. This very fact alone bears witness to the ability and resilience of Polish tobacco farmers. It is also a testimony to the proficiency of Polish tobacco scientists and agronomists, including those engaged in tobacco improvement programmes. One should bear in mind that tobacco production in Poland, a country of austere and non-typical tobacco growing conditions, has to rely mainly on domestically-bred cultivars.

VRG - black root rot resistant varieties
PVY resistant varieties (conventional, GMO)
TSWV resistant varieties


VRG - black root rot resistant varieties

The on-going tobacco breeding programme at IUNG focuses mainly on flue-cured (Virginia) tobacco but considerable attention is also given to Burley and dark-air cured tobacco. In the last decade, an array of new Virginia varieties have been developed and released to farmers. What those varieties have in common is that all of them are cytoplasmically sterile hybrids, and all have resistance to black root rot caused by the ubiquitous soil fungus Chalara elegans. The resistance to black root combined with improved curing and leaf quality characteristics was the main factor behind the success of the new varieties with farmers and tobacco leaf merchants in Poland. Designed as potential alternatives to the old-line variety Wi¶lica, increasingly preyed upon by black root rot, within a few years the new varieties all but replaced the old cultivar that had dominated the Polish flue-cured tobacco market for many years.

VRG 1 - a variety that thrives best on moderately fertile soils. Readily responds to high level of native nutrients in the soil and to increased fertilization with abundant if not over-luxurious growth. Curability of VRG 1 is very good but it tends to produce leaves with thin body, especially when grown at high plant densities on rich soils.

VRG 2 - a variety for moderately rich soils but with nutritional requirements slightly higher than those of VRG 1. Prefers soils of good tilth with a fair content of coarse fractions. Produces medium heavy-bodied leaves of good curability. Given good management, performs better than the traditional Wi¶lica even in the black root-free environment. VRG 2 is the variety of choice with the major leaf merchants operating in the Polish market as its smoking characteristics resemble most closely those of Wi¶lica.

VRG 3 - prefers soils in good tilth with good water retention capabilities. Because of a relatively shallow root and weak root system VRG 3 is sensitive to periodic soil water deficits (droughts) and is therefore not a good choice for light sandy soils especially those with defective water relations. VRG 3 gives moderately high yields and its leaves tend to mature slowly, especially in cool weather. The cured leaves are distinguished for thick body and open grainy texture. Because of variable yields, VRG 3 is the least popular of the new varieties.

VRG 4 - similar to VRG 3 in all major agronomic characteristics except the yields. VRG 4 is a good yielder, better than VRG 2, and readily produces heavy bodied, open-textured cured leaves provided they are harvested at full ripeness. Like VRG 3, in cool summers it matures slowly and is therefore not suitable for northern regions of the country.

VRG 5 TL - the most recent addition to the line of new black root rot resistant varieties and also the most innovative one. Unlike the previous four varieties which are conventional simple F1 hybrids, VRG 5 TL is a three-line hybrid which means that one of its parents is also a hybrid rather than an inbred line. Unlike the other varieties, which are variations of the relatively slow growing, medium-late-flowering type of Wi¶lica, VRG 5 TL is a fast growing, early flowering variety that thrives on many kinds of soils. It is tolerant of moderate excess of water but should be avoided on soils prone to drought, especially in the spring. If managed properly, VRG 5 TL produces high yields of well-cured, open-textured and heavy-bodied leaves. It seems to be a very successful newcomer to the flue-cured market in Poland, with the first on-farm tests performed only two years ago and seed orders for the coming 2011 season exceeding 3 kg (enough to plant ca. 450 ha) and limited with the availability of seeds.

Tobacco breeding in Poland can be regarded as part of a larger tobacco improvement effort conducted in several European countries such as Germany, France, Hungary, Greece, Croatia, Spain and some others. There is an idea to bring this effort together under the auspices of AERET (Association Europeenne pour la Recherche et l'Experimentation Tabacole), a newly established European organization of tobacco growers and agronomists with the purpose to promote information-sharing on tobacco leaf production and to organize common research in tobacco. Within the framework of AERET, IUNG-PIB takes part in building the network of joint tobacco variety experiments and participates in the compiling of the European catalogue of tobacco varieties.


VRG 2 - the most popular in the line of new black root rot resistant hybrid varieties of flue-cured tobacco developed at IUNG-PIB



Field of VRG 4 - black root rot resistant flue-cured variety from Pulawy



Field of VRG 5TL - first three-line hybrid of flue-cured tobacco resistant to black root rot



PVY resistant varieties (conventional, GMO)



TSWV resistant varieties

As a result of breeding researches the PW-DH tobacco lines with a high level of TSWV resistance were obtained. A single-dominant model of resistance was found in these lines and they are a valuable initial breeding material in developing acceptable cultivars of a good quality and with TSWV resistance.

 
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