DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 1-2/1966 str. 135 <-- 135 --> PDF |
INTERSPECIFIC HYBRIDS BETWEEN WHITE WILLOW (Salix alba L.) AND CRACK WILLOW (Salix fragilis L.) (Contributed paper) by ANTE KRSTINIC Forestry Faculty, Zagreb, Yugoslavia. During a three-year work on the selection of White Willow, we visited a number of localities in Yugoslavia. According to A. Krstinić — M. Vidaković (1) from the genetic point of view the populations of White Willow on the surveyed localities distinguish themselves in a wide range of variability. This variability does not manifest itself only in the essential characteristics of the habit (straightness, branching), but also in the basic taxonomical characteristics (leaf, buds, colour of shoots, etc.). In the region of the Sava River the representatives of the population of White Willow have to a great percentage bent and spirally grown stems, thick branches which are relatively lowplaced on the stem, while the branch angle is small. Along the Drava River we found a population of White Willow whose representatives exhibit stems of long commercial lengths, with marked staightness, free of spiral grain, and great growing power. In these populations we also found the best specimens of plus trees. Several of these best plus trees with respect to their taxonomic characteristics could not be determined either as being typical individuals of Salix alba L. or Salix fragilis L. Thus we were led to assume that in this case we had to deal with the interspecific hybrids between these two species. After a detailed survey of a wider area along the Sava and Drava Rivers we found that along the Sava River Crack Willow (Salix fragilis L.) is very scarce and that it occurs only in clearings and at the borders of stands. In the area of the Drava River Crack Willow (Salix fragilis L.) occurs very frequently and not only that it appears in clearings and at the stand borders but is largely interspersed within the population of White Willow. In the area of the park forest of »Maksimir«, Zagreb, along the brook of »Bliznec« there occurs also Crack Willow together with White Willow, but in that locality too we found specimens of arborescent Willows which respect to the taxonomic characteristics do not represent pure species either. In order to verify our assumption that in this case we had actually to deal with interspecific hybrids of White and Crack Willow we collected during 1964/65 the seed from a number of female plus trees and raised plants, while the male plus trees were crossed with pure species of Salix alba L. and Salix fragilis L. On analysing the generative progenies we found that also in that case we were considered with interspecific hybrids of the mentioned two species because in the progeny there appear pure parent |
| ŠUMARSKI LIST 1-2/1966 str. 136 <-- 136 --> PDF |
species (Salix alba L. and Salix fragilis L.) as well as intermediate types resembling the mother and father respectively. Basic mensurational data concerning the mentioned hybrids from the region of the Drava River and the park forest »Maksimir« are given in Table 1. Mean No. Age; Height D. b. h. Volume annual of Sex years m. cm. cu. m. increment Locality Remarks tree cu. m. 15 39 28,0 47,0 1,961 0,0502 Crni Jarci (Đurđevac) Determinated as: S. alba L. x S. frag. L. 22 M 11 22,0 32,0 0,743 0,0675 Limbuš (Đurđevac) S. frag. L. S. alba L. x 23 F 30 28,0 64,0 3,716 0,1242 Maksimir (Zagreb) S. alba L. x S frag. L. 24 M 30 22,0 48,0 1,701 0,0568 Maksimir (Zagreb) S. frag. L. S. alba L. x From the tree No. 24 was not raised a generative progeny but on the basis of taxonomic characteristics we assume that it is also an interspecific hybrid. As can be seen from the enclosed table the interspecific hybrids between White and Crack Willow and between Crack and White Willow distinguish themselves by their vitality. E. Weber (4) states that between the above- mentioned species could be found individuals of excellent qualities with regard to the essential characteristics of habit, and in addition, with high growth rates. On the basis of observations made on the mentioned hybrids and on the ground of results of the controlled hybridisation between these two species it must be assumed that the reciprocal hybrids are not equal but resemble to the one or other species in dependence on which species functions as the female parent. We assume that in these cases we have the effects of matroclinal inheritance. The species Salix alba L. and Salix fragilis L. are easy to cross with one another. Fertile are also the interspecific hybrids of these two species. In order to verify our hypothesis that the interspecific hybrids between White and Crack Willow are of greater vitality than pure parent species we raised during 1964/65 the interspecific hybrids Salix fragilis L. x Salix alba L. We also wanted to find out whether the populations along the Drava River are actually of greater vitality than these along the Sava River, or whether the differences in vitality are conditioned by more favourable environmental conditions along the Drava River. Therefore we raised in 1964 a generative progeny from one population occuring along the Drava River (Bakovci— Đurđevac), and from one population inhabiting the area along the Sava River (Osman Polje — Lipovljani). In the population »Bakovci« the seed was collected from 4 trees, and in the population »Osman Polje« from 6 trees. |
| ŠUMARSKI LIST 1-2/1966 str. 137 <-- 137 --> PDF |
Data concerning heights of the interspecific hybrids (from 1964) and seedlings of White Willow from the mentioned populations are presented in Table 2.* Ser. Species Population No. of Heights No. data cm »t« — value 1 Salix alba L. Bakovci 122 202,21 1:2 = 11,6047*** 2 Salix alba L. Osman Polje 434 128,13 1:3 = 0,8514 3 Salix frag. L. x 9 186,22 3:2 = 3,2249** Salix alba L. In Table 2 is visible that the representatives of the population »Bakovcihave greater heights than the representatives from the population »Osman Polje«, and that they differ significantly at a level of 0,1%. Between the hybrids and the population »Bakovci« there is no significant, difference, while if compared with the population »Osman Polje« they are superior and differ significantly at a level of 1%. Between the population »Bakovci« and that of »Osman Polje« there exist not only differences in the intensity of height and diameter growth but also differences in the branch angle, colour of shoots and the time of flushing and seed setting. The arithmetic mean of the branch angle is greater in oneyear- old seedlings from the population »Bakovci« than of one-year-old seedlings from the population »Osman Polje«. As to this characteristic a significant difference at a level of 1% in the lower 1/3 of the seedling height exists. The colour of shoots in seedlings from the population »Osman Polje« does not show a greater variability and it is light-red in all representatives of the population, while in the population »Bakovci« it ranges from yellow, light-green, dark-green, light-red to chocolate brown. As regards the flushing and seed setting it was found that the individual representatives from the population »Bakovci« approach the interspecific hybrids Salix alba L. x Salix fragilis L. According to J. Wright (5) in the centre of occurence of two species of the same genus between which a hybridisation is feasible there comes to s migration of the genes from one species to another. Because on the locality »Bakovci« there exists the possibility of the intergradation between the species Salix alba L. and Salix fragilis L. It can be assumed that in this case we are also concerned with introgression, i.e. that the representatives of these populations contain also the genes of Salix fragilis L. The population »Osman Polje« is small and relatively isolated and perhaps here we also have the effects of inbreeding which brought this population to a greater homozygosity. On the basis of what precedes it would seem that the representatives of the population of White Willow posses a greater vitality and a more beautiful habit on those locations where within the population of White Willow is interspersed also Crack Willow, i.e. that probably also in these cases we are concerned with introgression. Further, we assume that the interspecific hybrids between these two species are more vital and of a more beautiful habit than the pure species. Works in this direction are in progress. * Measurements were taken in the second half of August 1965, i.e. in the middle of the second growing period. |
| ŠUMARSKI LIST 1-2/1966 str. 138 <-- 138 --> PDF |
Kratki sadržaj MEDUVRSNI HIBRIDI IZMEĐU BIJELE VKBE (SALIX ALBA L.) I KRTE VRBE (SALIX FRAGILIS L.) Tokom trogodišnjeg rada, na selekciji bijele vrbe, obišli smo više lokaliteta na području Jugoslavije. Predstavnici iz populacija bijele vrbe sa područja rijeke Savs, imaju u velikom postotku kriva, usukana debla, debele grane, koje su smještene srazmjerno nisko na deblu, a kut insercije im je malen. Uz rijeku Dravu našli smo populacije bijele vrbe, čiji predstavnici imaju veliku tehničku dužinu debla, izrazito pravna, neusukane žice, sa velikom sposobnošću prirašćivanja. U ovim populacijama nalazili smo i najljepše egzemplare plus stabala. Neka od ovih najljepših plus stabala po taksonomskim karakteristikama nisu se mogla determinirati kao tipične vrste Salix alba L. niti kao Salix fragilis L. Ovo nas je navelo na predpostavku, da se u ovom slučaju radi o međuvrsnim hibridima između ove dvije vrste. Detaljnijim pregledom šireg područja uz rijeke Savu i Dravu, konstatirali smo, da je krta vrba (Salix fragilis L.) uz rijeku Savu rijetka, da se javlja samo na rubovima sastojina, a da je ona na području rijeke Drave vrlo česta i da se ne javlja samo na čistinama već da dolazi uprskana unutar populacije bijele vrbe. Da bi provjerili našu predpostavku, da se u ovom području zaista radi o međuvrsnim hibridima između bijele i krte vrbe, tokom 1964/65 godine sa nekih ženskih plus stabala sakupili smo sjeme i uzgojili biljke, a muška plus stabla smo križali sa čistim vrstama Salix alba L. i Salix fragilis L. Nakon analize generativnog potomstva ustanovili smo, da se u ovom slučaju stvarno radi o međuvrsnim hibridima spomenute dvije vrste, pošto se u potomstvu javljaju čiste roditeljske vrste (Salix alba L. i Salix fragilis L.), kao i intermedijarni tipovi, slični majci, odnosno ocu (hibridu). Iz tabele 1 na temelju prosječnog godišnjeg prirasta vidimo, da se međuvrsni hibridi bijele i krte vrbe odlikuju visokom vitalnošću. Na temelju opažanja vršenih na spomenutim hibridima, te na temelju rezultata kontrolirane hibridizacije između ove dvije vrste konstatiramo, da recipročni hibridi nisu jednaki, već da su slični jednoj ili drugoj vrsti, ovisno o tome, koja vrsta fungira kao ženski roditelj. Predpostavljamo, da se u ovim slučajevima radi o efektima matroklinog nasljeđivanja. Iz tabele 2 se vidi, da je i generativno potomstvo od matičnih stabala iz populacija sa područja rijeke Drave veće vitalnosti od generativnog potomstva koje potječe od matičnih stabala iz populacija sa područja rijeke Save. Također je iz iste tabele vidljivo, da umjetno proizveden međuvrsni hibrid između krte i bijele vrbe ne zaostaje po visinskom prirastu za najboljim generativnim potomstvom bijele vrbe sa područja rijeke Drave, a da je bolji od generativnog potomstva sa područja rijeke Save. Populacije bijele vrbe sa područja rijeka Drave i Save ne razlikuju se samo u visinskom prirašćivanju, već također posloje razlike i u kutu insercije grana, u boji izbojaka te u vremenu listanja i plodonošenja. Kako je varijabilnost spomenutih karakteristika veća kod predstavnika iz populacija sa područja rijeke Drave, a prije smo spomenuli, da je u ovim populacijama uprskana i krta vrba, to smo predpostavili da se u ovom slučaju radi o introgresiji, tj. da predstavnici iz ove populacije sadrže i gene od Salix fragilis L. LITERATURE 1. Krsti nić A. — Vidaković M. (1964): Prilog rješavanju problema uzgoja bijele vrbe. (A contribution to the solution of the problem of cultivation of White Willow — Salix alba L.). Topola, 8/44, pp. 10—17. 2. LeClergE. L. — W. H. Leonard — A. G. Clark (1962): Field Plot Technique. Burges Publishing Company, Minneapolis, 373 pp. 3. Tavča r Aloi s (1952): Osnove genetike. (Elements of Genetics). Škol. knjiga, Zagreb, 493 pp. 4. Webe r E. (1963): Genetische, planzenzüchterische und baumschultechnischc Untersuchungen an Baumweiden, München, 144 pp. q 5. Wrigh t J. W. (1962): Genetics of Forest Tree Improvement. FAO, Rome, 399pp. 6. Wrigh t J. W. (1963): Hybridization between Species and Races. World Consultation on Forest Genetics and Tree Improvement, 2 b, Stockholm. 7. 2 ufa L. (1958): Tablice drvnih masa vrbe (Salix alba L.). (Volume Tables for White Willow — Salix alba L). Šum. Društvo A. P. Vojvodine, Novi Sad, 29 pp. |