Varying chromosome composition of 56-chromosome wheat x Thinopyrum intermedium partial amphiploids P. M. BANKS CSIRO, Division of Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia S. J . X u Agricultural Sciences, Beijing, Institute of Crop Germplasm Resources, Chinese Academy People's Republic. o f China R. R.-C. WANG USDA-ARS Forage and Range Research, Utah State University, Logan, UT 84322-6300, U.S.A.

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AND

P. J. LARKIN CSIRO, Division of Plant Industry, GPO Box 1600, Canberra, ACT 2601, Australia Corresponding Editor: R. Appels Received September 15, 1992 Accepted October 26, 1992 BANKS,P. M., XU, S. J., WANG,R. R.-C., and LARKIN,P. J. 1993. Varying chromosome composition of 56-chromosome wheat X Thinopyrum intermedium partial amphiploids. Genome, 36: 207-2 15. Thinopyrum intermedium (2n = 42) is a source of many potentially useful genes for wheat improvement. Many partial amphiploids have been produced between Th. intermedium and Triticum aestivum that are fertile and stable. These partial amphiploids all have 56 chromosomes, including seven pairs of chromosomes from Th. intermedium. To explore the genomic composition of these lines, meiotic analysis was conducted on 32 hybrid combinations between eight different partial amphiploids. All but two of the chosen parents were distinguishable on the basis of perenniality, head morphology, and reactions to leaf, stripe, and stem rusts and to barley yellow dwarf virus. Chromosome pairing in the hybrids clearly indicated that all but two of the partial amphiploids differed in their composition of Thinopyrum chromosomes. The differences varied from one to five chromosomes. This confirms molecular evidence that the extra genome of the octoploid partial amphiploids is a variable synthetic genome combining chromosomes of the three Thinopyrum genomes E, J, and X. Though the extra synthetic genomes vary widely between different octoploids, they are nevertheless stable once formed. It is argued that the failure to establish these octoploid amphiploids as a new crop is a consequence of their differing chromosome complements, which makes it impractical to interbreed them. Key words: Thinopyrum, Agropyron, agrotriticum, wheat, amphiploid, octoploid, barley yellow dwarf virus, rust. BANKS,P. M., XU, S. J., WANG, R. R.-C., et LARKIN,P. J. 1993. Varying chromosome composition of 56-chromosome wheat X Thinopyrum intermedium partial amphiploids. Genome, 36 : 207-2 15. Le Thinopyrum intermedium (2n = 42) est une source de plusieurs genes potentiellement utiles pour l'amelioration du ble. Plusieurs lignkes amphiploi'des partielles, fertiles et stables, ont ete produites entre le Th. intermedium et le Triticum aestivum. Toutes ces lignees amphiploi'des ont 56 chromosomes, incluant sept paires de chromosomes de Th. intermedium. Pour explorer la composition genomique de ces lignkes, 32 combinaisons hybrides entre huit lignkes amphiploi'des partielles diffkrentes ont fait l'objet d'analyses mkiotiques. Tous les parents, sauf deux exceptions, ont pu &re reconnus d'apres les traits suivants : la pkrennitk, la morphologie de l'kpi, les rkactions a la rouille des feuilles et des tiges, a la rouille jaune strike, ainsi qu'au virus du nanisme jaune de l'orge. Chez les hybrides, l'appariement des chromosomes a clairement indiquk que la composition en chromosomes de Thinopyrum ktait diffkrente chez toutes les lignkes amphiploi'des, sauf deux. Les diffkrences ont varik de un a cinq chromosomes. Ceci confirme l'kvidence molkculaire que le gknome surnumkraire des amphiploi'des partielles octoploi'des est un gknome synthktique variable, combinant les chromosomes de trois gknomes de Thinopyrum, soit les E, J et X. Bien que les gknomes synthktiques aient varik grandement entre les diffkrentes lignkes octoploi'des, ils ont kt6 nkanmoins stables une fois formks. L'hypothese est avancke que I'incapacitk d'obtenir que ces amphiploi'des octoploi'des s'ktablissent comme nouvelles rkcoltes est une conskquence des diffkrences dans les complkments chromosomiques qui rendent les croisements impraticables. Mots cle's : Thinopyrum, Agropyron, agrotriticum, amphiploi'de blk octoploi'de, virus du namisme jaune de l'orge, rouilles. [Traduit par la rkdaction]

Introduction In addition to being a valuable perennial pasture species, the intermediate wheatgrass Thinopyrum intermedium (Host) Barkworth & D.R. Dewey, syn. Agropyron intermedium (Host) Beauvois, syn. Agropyron glaucum ( Desf. ex DC.) Roemer & Schultes, syn. Elytrigia intermedia (Host) Nevski, syn. Elymus hispidus (Opiz) Melderis has long attracted attention for potential wheat improvement. P r ~ n k dIn C ~ n n d n/ Irnpr~rnenu Canada

Desirable characteristics of Th. in termedium of potential value for wheat improvement include perennial habit, stress tolerance (drought and cold), and disease resistance (rusts and viral diseases). Several wheat x Th. intermedium hybrids were produced in the 1920s and 1930s in programs in the former Soviet Union (Tsitsin 1960), Canada (Peto 1936), U.S.A. (Smith 1943), and Germany (Wakar 1936). Initial high expectations for wheat improvement were not

GENOME. VOL. 36. 1993

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TABLEI . Reaction to barley yellow dwarf virus (BYDV) of wheat X Thinopyrum intermedium partial amphiploids (2n = 56) from differing sources Identification

Line

CPI 109 386

TAF 46

CPI CPI CPI CPI CPI CPI CPI

1 15 734 115 735 1 15 730 1 15 736 1 1 5 737 1 15 738 1 15 739

Zhong Zhong Zhong Zhong Zhong Zhong Zhong

I 2 3 4 5 6 7

Reaction to BYDV-PAV

Source Y. Cauderon, France (Cauderon 1966) Chi Ser-Yui Heilongjiang, P.R.C. (Chi et al. 1979)

CPI 114 084

OK 721 1542

Sando via A. Comeau, Canada

CPI 1 14 085 CPI 116 221

Otrastayushchaya 38 PGR- 18752A

Russia via A. Comeau. Canada

CPI 115 731

Zhong 1001

Shanxi via Zhou G.H., P.R.C.

CPI 120 838 CPI 120 840 CPI 120 839

Zhong 1001 Zhong 89 1 Zhong 96-8

Shanxi via Sun Shan-cheng, P.R.C.

CPI 119 107 CPI 119 108

Summer 1 Summer 2

Shanxi via Yang Ya-fan, P.R.C.

NOTE: R, resistant; S, susceptible.

realized. Some interest in the transfer of genes from Th. intermedium to wheat was rekindled as improved techniques of transferring genes between species became available (Dewey 1984). Resistances to wheat rusts have been transferred from Th. intermedium to wheat (Cauderon et al. 1973: Ortiz et al. 1986; Wienhues 1973, 1979). Resistance to wheat streak mosaic virus (WSMV) has been identified on a group-4 Th. intermedium chromosome and transferred to wheat (Wells et al. 1982; Wang et al. 1977). Brettell et al. (1988) identified resistance to barley yellow dwarf virus (BYDV) conferred by the P arm of a group-7 Th. intermediurn chromosome. This resistance has recently been transferred to wheat (Banks et al. 1990; P.M. Banks and P.J. Larkin, unpublished data). However, the genetic resources of the intermediate wheatgrass complex still remain largely unexploited for wheat breeding purposes. Many reports of hybrids and intermediate types of wheat X Th. intermedium attest that hybrid production is not a barrier for the transfer between the species. The F l hybrids are sterile, but if they are open pollinated some seeds are occasionally set (Verushkin and Shechurdin 1933 and others). Many fertile and stable derivatives have been produced from hybrids and invariably they have been found to have a set of seven chromosome pairs of Th. intermedium in addition to the wheat complement. Evidently, unreduced gametes and elimination of Thinopyrum chromosomes in early generations are involved in the development of these 56-chromosome partial amphiploid types. Fertile, complete amphiploids (84 chromosomes) of wheat X Th. intermediurn appear to be unknown and our own attempts to produce a fertile amphiploid by use of colchicine were unsuccessful.

Thinopyrum intermedium (2n = 42) is a segmental autoallohexaploid (Dewey 1962). The genome designation varies between authors, but there is general agreement that the genomic composition of Th. intermedium consists of two very similar genomes and a third genome of unknown homology. The two similar genomes have been designated as E and J, or E l and E,, or J , and J, and the other genome designated as X or Z or N. Some recent data suggests the X genome may be related to the S genome of Pseudoroegneria (Z.-W. Liu and R.R.-C. Wang, in preparation). In this paper we use the designation EEJJXX for Th. intermediurn and recognize that the E and J genomes are very similar and could be combined as suggested by Dewey (1984). The purpose of the investigation reported here was to elucidate the composition of the seven pairs of Thinopyrum chromosomes of a number of 56-chromosome partial amphiploid lines. Following crosses between differing 56-chromosome lines, meiotic pairing in the F, hybrids was examined. The reactions of the differing 56-chromosome lines to barley yellow dwarf virus (BYDV) and wheat rusts were tested.

Materials and methods The sources of 17 differing 56-chromosome lines are indicated in Table I. The Russian lines Otrastayushchaya 38 and PGR-18752 are strongly perennial and the other 15 lines have annual habit. A line described by Xin et al. (1988) and introduced into Australia as CPI 107735 appears to be the same as Zhong 5 (CPI 115737) from Heilongjiang Province rather than Zhong 4 as it was known. The spike morphology and other phenotypic characteristics of CPI 107735 and CPI 1 15737 appear identical. Two other introductions into Australia,

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BANKS ET AL

FIG. 1. Spikes of the wheat X Th. intermedium partial amphiploids (2r1 = 56) Zhong I , Zhong 2, Zhong 4, Zhong 5, Zhong 6, and Zhong 7. These lines were produced in Heilongjiang Province, P.R.C.

FIG. 2. Spikes of the wheat X Th. intermedium partial amphiploids (2n = 56) OK721 1542 and Otrastayushchaya 38. OK7211542 was produced in North America and Ostrastayushchaya 38 is a perennial line from Russia.

FIG. 3. Spikes of Th. intermedium, the winter wheat Vilmorin 27, and the partial amphiploid TAF46. The partial amphiploid was isolated by Y. Cauderon, France, following crossing of the Thinopvrum to Vilmorin 27 and selection in subsequent generations.

CPI 109263 and CPI 109522 both known as "Zhong 4 awned," appeared to be identical to the Zhong 4 (CPI 115736) from Heilongjiang Province. The octoploid line known as Zhong 1 from Heilongjiang Province (CPI 115734) is obviously a differ-

ent line to the "Zhong 1" described by Sun (1981), which was reported to have only 44 chromosomes. Reactions of the 56-chromosome lines to BYDV were evaluated by ELISA following artificial inoculation of seedlings. Ten

GENOME, VOL. 36, 1003

TABLE2. Reaction to Australian pathotypes of leaf, stripe, and stem rust of nine wheat X Thinopyrum intermedium partial amphiploids (2n = 56) Leaf rust ( 1 04-2,3,6,7)"

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Zhong Zhong Zhong Zhong Zhong Zhong Zhong

(1

Stripe rust 10 E 143 A+)'

Stem rust (343- 1,2,3,5,6)'

1

2 3 4 5 6 7

Otrastayushchaya 38 "For sources of each line see Table 1. he rust scoring symbols are as follows: 0, immune; :. fleck = highly resistant: I . resistant; 2, 3, 4, increasing susceptibility. The scores are modified with - and + eg. 2-, slightly more resistant than 2: :-, nearly immune. Combinations of symbols indicate a range of reaction types on the one plant; e.g., :I, reaction varies from ; to 1 33+, reaction varies from 3 to 3+. When diff'erent plants of the one accession give different reactions, this is indicated (e.g., 7p2,lp3 means seven plant4 reacted with 2 and one plant reacted with 3).

or more 1-week-old seedlings of each line were individually inoculated with 10-20 viruliferous aphids. The viruliferous aphids were produced by propagating Rhopulisiphum padi on barley (cv. Malebo) and then feeding the aphids for 3 days on oats (cv. Cooba), which had previously been infected with an Australian BYDV-PAV isolate. Following inoculation, the aphids were sprayed with pyrethrins (Slayafe Hortico Pty Ltd.) and the seedlings were maintained in growth cabinets at 18°C days - 16°C nights with a 12-h photoperiod of After 3 weeks growth, sap extracts were 300 p,E:m-'.sp'. prepared from 0.5-g samples of the youngest fully expanded leaves and assayed for virus content using ELISA. The double antibody sandwich ELISA for detecting BYDV has been described previously (Sward and Lister 1987; Xin et (11. 1988). Immunoglobulins were prepared from rabbit antiserum produced against the MIX-A1 isolate of BYDV (Waterhouse et al. 1986). Absorbance at 405 nm (A,,,) was read 1 h after the addition of substrate. The A,,, values for seedlings of partial amphiploid lines were compared with values for inoculated wheat (cv. Sunstar, susceptible control) and inoculated CPI 107735 (resistant control). Both field and laboratory tests have previously demonstrated that CPI 107735 is resistant to BYDV (Xin et al. 1988; Zhou et al. 1990). Reactions to Australian pathotypes of leaf rust and stem rust were evaluated according to McIntosh et al. (1982). Assessment of reactions to Australian pathotypes of stripe rust followed the methods described by Wellings et al. (1988). Reciprocal crosses between the partial amphiploid lines TAF46, Zhong 1, Zhong 2, Zhong 3, Zhong 4, Zhong 5, Zhong 6, and Zhong 7 were made. The F, plants were grown under glasshouse conditions. Young spikes for observation of meiotic pairing were fixed in Carnoy's solution. Anthers were squashed in modified carbol fuchsin or 1.5% acetocarmine.

Results Phenotypic differences between the 56-chromosome lines were clearly evident. Spike morphology differed considerably (Figs. 1, 2, and 3) with the exception of Zhong 3 (not shown) and Zhong 5. The overall phenotypic appearance of Zhong 3 and Zhong 5 was very similar. Twelve of the 56-chromosome lines were found to be resistant to BYDV, but four were susceptible (Table 1). Two accessions, both known as Zhong 1001, but introduced to Australia from differing sources, had contrasting reactions

to BYDV. Zhong 3, Zhong 4, Zhong 5, Zhong 6, and Zhong 7 were highly resistant to important Australian pathotypes of leaf rust, stripe rust, and stem rust (Table 2), though there were preliminary indications of heterozygosity in Zhong 1, Zhong 4, and Zhong 6 for stem rust reaction only. The other octoploid lines tested were not as resistant to the rusts. OK 721 1542 was resistant to BYDV but susceptible to stripe rust (Tables 1 and 2). Observations of meiotic chromosome pairing in selfed progeny of a number of 56-chromosome lines indicates that the octoploids are relatively stable. The most common meiotic metaphase 1 configuration was 28 bivalents (Table 3). In hybrids between Zhong 3 and Zhong 5 similar regular meiotic pairing (28 bivalents) was observed indicating close homology between each of the wheat and Thinopyrurn chromosomes of these two amphiploids. It is possible that Zhong 3 and Zhong 5 are derived from the same octoploid. Observations of meiotic pairing in all other examined hybrid combinations indicated that there was close homology between only 23-27 chromosomes of the respective parents [Table 3, Fig. 4). In the hybrid combinations Zhong 7 X Zhong 6, Zhong 6 X Zhong 5, Zhong 4 X Zhong 7, Zhong 4 X Zhong 6, and Zhong 4 X Zhong 5 more than 50% of the pollen mother cells (PMCs) observed had two univalents and a mean number of bivalents of about 27 (Table 3, Fig. 4). These results suggest that the chromosome complements of the respective parents of each hybrid differ by only one chromosome pair. At meiotic metaphase 1 in the hybrid Zhong 7 X Zhong 5 there was an average of 26 bivalents in addition to one trivalent and one or two univalents. The results suggest that the octoploid lines can be divided into three groups: A (Zhong 1 and Zhong 2), B (Zhong 3, Zhong 4, Zhong 5, Zhong 6, and Zhong 7), and TAF46. In hybrid combinations between groups A and B the number of univalents observed in PMCs ranged from 4 to 14 but was usually in the range of 6-10. The average number of multivalents (I11 + IV + V) ranged from 0.42 to 1.32 per PMC (Table 3). In all hybrid combinations involving TAF46 several univalents in addition to multivalents were observed at meiotic metaphase I. In F , hybrids of group B types X TAF46, the number of

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B A N K S ET AL.

Fig. 4. Meiotic metaphase I in F, hybrids between various wheat X Th. intermediunl partial amphiploid lines. (u) Zhong 4 X Zhong 2 (12 I + 12 ring I1 + 6 rod I1 + 1 I11 + IV). (b) Zhong 4 X Zhong 6 (2 I + 23 ring I1 + 4 rod 11). (c) Zhong 4 X Zhong 5 (2 I + 24 ring I1 + 1 rod I1 + 1 IV ). ( d ) Zhong 5 X TAF46 (8 I + 13 ring I1 + 8 rod I1 + 2 111). (e) Zhong 2 X TAF46 ( 1 1 I + 13 ring I1 + 5 rod I1 + 1 I11 + 1 IV). ( f ) Zhong 7 X Zhong 6 (2 I + 20 ring I1 + 7 rod 11). univalents ranged from 2 to 11 but was usually between 4 and 10. The average number of bivalents ranged from 22 to 24.2 and the frequency of multivalents ranged from 0.45 to 1.24 per PMC. In the hybrid Zhong 2 (group A) X TAF46 the average number of bivalents was 20.6 and the usual number of univalents 6-10. Many PMCs contained one trivalent and one quadrivalent. No major differences in meiotic metaphase I chromosome configurations between reciprocal crosses were evident. However, the frequency of two univalents in combi-

nations of Zhong 6 and Zhong 4 as well as Zhong 5 and Zhong 4 did vary and was associated with minor variation (about 0.5) in the average number of bivalents per PMC.

Discussion A number of authors have assumed that the genomic composition of wheat X wheatgrass partial amphiploids could simply be designated ABDE (or ABDJ) (Miao et al. 1988; Ohlendorf 1955; Zhong and Mu 1983). Results of this investigation are consistent with the conclusions of

212

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GENOME, VOL. 36. 1093

h

h

h

l n m m m m l n \ ~ ~ ~ P J 4 P J 3 3 - 3 3

c on

on

~

~

0 C

X F

c

~

0 C

X F

F

b

C

X \

X D

\

\

6

C

X D

X D

\

w

f

i

w

w

F

~

~

w

X D

f X

\

D

i X

\

D

f

i

X l

n

2

X l

n

o n o n o n o n o n w e n o n e n o n o n c c c c c c c c c c c 0 0 0 0 0 0 0 0 0 0 0 C C C C C C C C C C C

e n e n o n o n c c c

c

0

C

0

C

0

C

0

C

6

Total no. of PMCs

49

41

39

43

36

46

43

18

38

45

10

46

13

31

27

Genotype

Zhong 4 X Zhong 7

Zhong4XZhong6

Zhong 4 X Zhong 5

Zhong 4 X Zhong 2

Zhong 4 X Zhong 1

Zhong 3 X Zhong 5

Zhong 3 X Zhong 2

Zhong 3 X Zhong 1

Zhong 2 X TAF46

Zhong 2 X Zhong 6

Zhong 2 X Zhong 4

Zhong 1 X Zhong 7

Zhong 1 X Zhong 5

Zhong 1 X Zhong 4

Zhong 1 X Zhong 3

0.91

0.31

0.17

0.39

0

0.76

0.49

2

0.09

0.05 0.56

1

3

4

5

6

7

8

Frequency of univalents 9

TABLE3 (concluded)

10

11

12

13

14

Ring

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Rod

I1

Total

I11

Mean no. of:

IV

V

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214

GENOME, VOL. 36, I993

Sinigovets (1987), Xin et al. (1988), and Zhang et al. (1992) that the 14 Thinopyrurn chromosomes of the octoploid intermediate types are not an intact genome of Th. intermedium but a synthetic genome combining chromosomes from the three genomes E, J, and X. The irregular meiotic chromosome configurations in hybrids between differing 56-chromosome types indicates that the composition of the synthetic genome varies between the octoploid intermediate types. The wheat backgrounds of the various 56-chromosome types are known to be different and some of the irregular meiotic pairing may be a consequence of translocations between wheat chromosomes. However, most of the chromosomes observed as univalents or multivalents in the F, hybrids are likely to have been Thinopyrum chromosomes. We conclude from the number of unpaired chromosomes in the hybrids studied here that more than nine Thinopyrum chromosomes in total are involved in the synthetic genomes of these particular octoploid types. Of the eight octoploid types that were crossed during this investigation, only Zhong 3 and Zhong 5 appeared to have identical chromosome complements. No phenotypic differences between Zhong 3 and Zhong 5 were identified and the two accessions my be derived from the same octoploid. He et al. (1989) also observed regular meiotic pairing in hybrids between Zhong 3 and Zhong 5. They classified Zhong 3, Zhong 4, and Zhong 5 together as type I1 allooctoploids and Zhong 1 and Zhong 2 as type I allooctoploids and concluded that type I allooctoploids carried one of the genomes of intermediate wheatgrass and type I1 allooctoploids another of the genomes. Thus 14 of the 21 Thinopyrum chromosomes would be represented in the two kinds of allooctoploids. He et al. (1989) did indicate minor differences between Zhong 1 and Zhong 2, but the results of meiotic pairing were not presented. They concluded that the Thinopyrum genomes carried by Zhong 3, Zhong 4, and Zhong 5 are identical. Our results suggest that within type I and type I1 the lines are similar but not identical. At meiosis in F, hybrids between type I and type I1 octoploids, He et al. reported 21 bivalents + 14 univalents in most PMCs of all hybrid combinations. We only observed one PMC with 14 univalents in all of the type I X type I1 hybrids analyzed. Further, the mean number of bivalents ranged from 21.2 to 23.4 and multivalent associations were very common. Thus, there appears to be homology between at least one or two Thinopyrum chromosomes between type I and type I1 56-chromosome lines. The multivalent associations are possibly the result of segmental interchanges in otherwise homologous E- and J-genome chromosomes (Wang 1985). It is difficult to precisely ascertain the extent of autosyndetic pairing between E- and J-genome chromosomes in the hybrid combinations examined because of the similar Thinopyrum and wheat chromosomes. appearance of Meiotic pairing in rye X intermediate wheatgrass hybrids indicated some autosyndetic pairing between E and J chromosomes from intermediate wheatgrass (Fedak and Armstrong 1986; Stebbins and Pun 1953; Zennyozi 1963). The activity of the Phl gene in wheat backgrounds reduces the degree of pairing between similar but not completely homologous chromosomes. Thus E and J chromosomes that frequently pair in rye hybrids may not do so in 56-chromosome wheat X Th. intermedium material. If the E and J genomes of Th. intermedium are assumed to be essentially homologous, the theoretical number of

56-chromosome partial amphiploid types with seven pairs of the 21 possible from Thinopyrum in addition to a full complement of wheat chromosomes is 27 = 128. If the E and J genomes are assumed to be nonhomologous, the theoretical number is 37 = 2187 because there would be three possible Thinopyrum chromosomes for each of the seven homoeologous groups. The actual number of partial amphiploid types that may be derived from wheat X Th. intermedium hybrids may be a fraction of the theoretical number because of the likelihood of preferential transmission of particular chromosomes. However, many partial amphiploid lines with differing combinations of Thinopyrum chromosomes have been isolated. If partial amphiploid lines that carry one or more differing Thinopyrum chromosomes are crossed, meiotic pairing in the F , hybrids will be irregular, as our results show, and may result in the loss of chromosomes in subsequent generations. The widely differing combinations of Thinopyrum chromosomes in 56-chromosome types is a major obstacle to the development of wheat X Th. intermedium octoploids as a crop plant (Sun 1981; Tsitsin and Lubimova 1963; Berezhnoi 1987). Classical plant breeding for improvement of the 56-chromosome types would be impractical unless several primary octoploids with similar chromosomal composition can be isolated to initiate such a program. Sinogovets ( 1987) isolated 32 disomic addition lines (2n = 44) derived from backcrosses to wheat of eight different 56-chromosome types. Following a study of crosses between these addition lines it was concluded that the synthetic Thinopyrum genome predominantly consists of chromosomes of the E and J genomes. This may be the case for many of the Russian octoploids. By means of in situ hybridization of chromosome preparations to a rye-derived X-genome specific repeated terminal sequence probe, Xin et a1 (1988) demonstrated that there are at least four pairs of X-genome chromosomes in Zhong 5 (Zhong 4, see Materials and methods). Using the same probe, L. Spindler and R. Appels (unpublished data) similarly demonstrated that there are at least two pairs of X-genome chromosomes in TAF46. Xin et al. (1988) also confirmed the presence of E and (or) J chromosomes in Zhong 5 by Southern hybridization using a probe that was isolated from Th. elongaturn. The reaction to BYDV of 56-chromosome types may depend on whether one particular chromosome is included among the seven pairs of the synthetic genome. BYDV resistance has not been found in any true wheats (Banks et al. 1990). Brettell et al. (1988) determined that there is a major BYDV resistance factor on the P arm of a group 7 chromosome. We are testing newly derived disomic addition lines to determine if other Thinopyrum chromosomes confer resistance to BYDV. Wienhues (1973, 1979) found that resistance to leaf rust, stripe rust, and stem rust were conferred by a single Thinopyrum chromosome. In material derived from TAF46, Cauderon et al. (1973) determined that resistance to the three rusts was conferred by three different Thinopyrum chromosomes. The strong rust resistance of the Chinese partial amphiploid Zhong 5 (Table 2) appears to be conferred by a single pair of Thinopyrum chromosomes (P.M. Banks, X. Chen, and R.A. McIntosh, unpublished data). Because only two of the differing partial amphiploids studied were perennials, the perennial habit also appears to be conferred by only a few Thinopyrum chromosomes.

B A N K S ET AL.

Acknowledgements

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We thank Lina Marx for assistance with plant crossing and ELISA screening. We also thank Dr. R.A. McIntosh, Plant Breeding Institute, University of Sydney, for conducting the rust screening. The research was supported by the Australian Centre for International Agricultural Research (Project 88 13). Banks, P.M., Xu, S.J., and Larkin, P.J. 1990. Sources of resistance to BYDV in wheat-related grasses. Proceedings, Aphid-Plant Interactions. Stillwater, Oklahoma. USDA-ARS, Oklahoma State University. Berezhnoi, P.P. 1987. Development of the ideas of N.I. Vavilov on distant hybridisation in wheat breeding (In Russian.). Sel. Semenovod. (Mosc.), 6 : 49-52. Brettell, R.I.S., Banks, P.M., Cauderon, Y., Chen, X., Cheng, Z.M., Larkin, P.J., and Waterhouse, P.M. 1988. A single wheatgrass chromosome reduces the concentration of barley yellow dwarf virus in, wheat. Ann. Appl. Biol. 113: 599-603. Cauderon, Y. 1966. Etude cytogknktique de l'kvolution du matkriel issu de croisement entre Triticum aestivilm et Agropyron intermedium. I. Crkation de types d'addition stables. Ann. Amelior. Plant, 16: 43-70. Cauderon, Y., Saigne, B., and Dauge, M. 1973. The resistance to wheat rusts of Agroppron intermedium and its use in wheat improvement. Proc. Int. Wheat Genet. Symp. 4th. pp. 401-407. Chi, S.Y., Yi, S.S., Chang, Y.H., Yi, K.H., and Son, F.Y. 1979. Studies on wheat breeding by distant hybridisation between wheat and Agropyron glaucum. Sci. Agric. Sin. 2: 1-1 1. Dewey, D.R. 1962. The genome structure of intermediate wheatgrass. J. Hered. 53: 282-290. Dewey, D.R. 1984. The genomic system of classification as a guide to intergeneric hybridization with the perennial Triticeae. In Gene manipulation in plant improvement. Edited by J.P. Gustafson. 16th Stadler Genet. Symp. 1984. pp. 209-279. Fedak, G., and Armstrong, K.C. 1986. Intergeneric hybrids between Secule cereale (2x) and Thinopyruin intermedium (6x). Can. J. Genet. Cytol. 28: 426-429. He, M.Y., Xu, Z.Y., Zou, M.Q., Zhang, H., Chen, D.W., Piao, Z.S., and Hao, S. 1989. The establishment of two sets of alien addition lines of wheat-wheatgrass. Sci. China, 32: 695-705. McIntosh, R.A., Miller, T.E., and Chapman, V. 1982. Cytogenetical studies in wheat. XII. Lr28 for resistance to Pucciniu recondita and Sr34 for resistance to P. gruminis tritici. Z. Ptlanzenzuecht. 89: 295-306. Miao, Z., Zhuang, J., and Han, H. 1988. Expression of various gametic types in pollen plants regenerated from hybrids between Tricicum-Agropyron and wheat. Theor. Appl. Genet. 75: 485-49 I . Ohlendorf, A. 1955. Weitere cytologische Untersuchungen an Weizen-Quecken-Bastarden. Zuechter, 25: 33 1-35 1 . Ortiz, L.T., GonzaIez, A., Chueca, M.C., and Cauderon, Y. 1986. Chromosomal structure of homozygous common wheat lines obtained from (wheat X Agropyron) X Aegilops speltoides derivatives. 11. A screening of paracentric inversions. Can. J. Genet. Cytol. 28: 906-912. Peto, F.H. 1936. Hybridization of Triticum and Agropyron. 11. Cytology of the male parents and F, generation. Can. J. Res. 14-C: 203-2 14. Sinigovets, M.E. 1987. Cytogenetic structure of 56-chromosome wheat-couchgrass (Triticum uestivum X Elytrigia intermediu) hybrids. Genetika, 23: 854-862. Smith, D.C. 1943. Intergeneric hybridization of Triticum and other grasses, principalIy Agropyron. J. Hered. 34: 2 19-224. Stebbins, G.L., and Pun, F.T. 1953. Artificial and natural hybrids in the Gramineae, tribe Hordeae. VI. Chromosome

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pairing in Secule cereule X Agropyron intermedium and the problem of genome homologies in the Triticinae. Genetics, 38: 600-608. Sun, S.C. 1981. The approach and methods of breeding new varieties and new species from Agrotriticum hybrids. Acta Agron. Sin. 7 : 51-58. Sward, R.J., and Lister, R.M. 1987. The incidence of barley yellow dwarf viruses in wheat in Victoria. Aust. J. Agric. Res. 38: 821-828. Tsitsin, N.V. 1960. The significance of wide hybridization in the evolution and production of new species and forms of plants and animals. In Wide hybridization in plants. Edited by M.V. Tsitsin. Israel Program for Scientific Translations, Jerusalem. pp. 2-30. Tsitsin, N.V., and Lubimova, V.F. 1963. On the formation of 56 chromosome wheat. (In Russian with English summary.) III Hybrids of remote crossings and polyploids. U.S.S.R. Academy of Sciences, Moscow. pp. 49-59. Verushkin, S.M., and Shechurdin, A.K. 1933. Hybrids between wheat and couchgrass. Fertile Tritic-um-Agropyron hybrids of great scientific and practical interest. J. Hered. 24: 329-335. Wakar, B.A. 1936. Cytologische Untersuchung uber F l der Weigen-Queckengras bastarde. Cytologia, 7 : 293. Wang, R.R.-C. 1985. Genome analysis of Thinopyrum be.s.srirrihic-id171and T elonguturn. Can. J. Genet. Cy to1 . 27: 722-728. Wang, R.R.-C., Liang, G.H., and Heyne, E.G. 1977. Effectiveness of ph gene in inducing homoelogous chromosome pairing in Agrotriticum. Theor. Appl. Genet. 51: 139- 142. Waterhouse, P.M., Gerlach, W.L., and Miller, W.A. 1986. Serotype-specific and general luteovirus probes from clone cDNA sequences of barley yellow dwarf virus. J. Gen. Virol. 67: 1273-1281. Wellings, C.R., McIntosh, R.A., and Hussain, M. 1988. A new source of resistance to Pucciniu .srriiformi.s f.sp. tricici in spring wheats (Tritic.uin aestivum). Plant Breeding, 100: 88-96. Wells, D.G., Kota, R.S., Sandhu, H.S., Gardner, W.S., and Finey, K.F. 1982. Registration of one disomic substitution line and five translocation lines of winter wheat germplasm resistant to wheat streak mosaic virus. Crop. Sci. 22: 1 277- 1278. Wienhues, A. 1973. Translocations between wheat chromosomes and an Agroppron chromosome conditioning rust resistance. Proc. Int. Wheat Genet. Symp., 4th. pp. 201-207. Wienhues, A. 1979. Translokationslinien mit Resistenz gegen Braunrost (Puccinici recondita) aus Agropyrum intermedium: Ergebnisse aus der Riickkreuzung mit Winterweizensorten. Z. Ptlantzenzuecht. 82: 149- 16 1. Xin, Z.Y., Brettell, R.I.S., Cheng, Z.M., Waterhouse, P.M., Appels, R., Banks, P.M., Zhou, G.H., Chen, X., and Larkin, P.J. 1988. Characterization of a potential source of barley yellow dwarf virus resistance for wheat. Genome, 30: 250-257. Zennyozi, A. 1963. F , hybrids between four species of Secale and Agropjyron intermeciium. Wheat Inf. Serv. 16: 30-3 I . Zhang, X.Y., Li, Z.S., and Chen, S.Y. 1992. Production and identification of three 4Ag (4D) substitution lines of Triticum ue.stir!ilm - Agropj.rorz: relative transmission rate of alien chromosomes. Theor. Appl. Genet. 83: 707-7 14. Zhong, G.C., and Mu, S.M. 1983. A study on cytological stability and karyotype of five octoploid Tritieljltrigiu types. Acta Agron. Sin. 9: 39-44. Zhou, G.H., Qian, Y.T., Cheng, Z.M., and Wang, L.Y. 1990. A cereal germplasm "Zhong 4" for resistance to barley yellow dwarf virus in China. In World perspectives on barley yellow dwarf. Edited by P.A. Burnett. CIMMYT, Mexico. pp. 394-395.