109which also refl ects crossability (Jalani and Moss 1980 ). The inhibitation or retarda-
tion of pollen tubes occurred mainly between the style base and the top of the
embryo sac , especially in the case of poorly crossable genotypes where both Kr
genes were present (Jalani and Moss 1981 ). Cameron and Reger ( 1991 ) showed that
a soluble, dialyzed lysate extracted from the ovaries of Hope and CS/Hope 5B
inhibited rye pollen tube elongation signifi cantly more than a similar lysate from
Chinese Spring ovaries.
Zeven ( 1987 ) published a list showing the percentage crossability with rye for
some 1400 varieties and lines of bread wheat, which included 76 wheat varieties
having a crossability with rye of 40 % or higher. These data could be used to select
wheat varieties for further interspecifi c crossing programs. There was one Hungarian
wheat cultivar, Bánkúti 1201, among the varieties with high crossability with rye.
The other two Hungarian wheat varieties in the list, Dioszegi 200 and Fleischmann
481, both have low crossability with rye. These are old varieties, which are no lon-
ger culti vated in Hungary. The crossability of the old Hungarian wheat varieties
Bánkuti 1201, Fleischmann 481, Székács 1055 and Alcsuti 21 with rye was tested
by Kiss and Rédei ( 1953 ) who analysed both seed set and the germination ability of
the hybrid seeds. Bánkuti 1201 always gave better seed set than F 481. Twenty-two
lines with good compatibility with rye were selected from the Bánkuti 1201 variety,
the best of which (Bánkuti 1201-4) gave more than 40 % seed set with rye over
several years (Kiss and Rajháthy 1956 ). A line with good crossability with rye was
also selected from the wheat cultivar Thatcher. More than 40 hexaploid wheat cul-
tivars were tested for crossability with rye by Kiss ( 1968 ) and the best seed set was
achieved with wheat cv. Bánkuti 1201. Belea ( 1992 ) also reported that a number of
biotypes selected from Bánkuti 1201 (B-1201-6, B 1201-10) gave h igher seed set
with Triticum monococcum than the cultivar average. This character was inherited.
4.3 Geographic Distribution of kr Alleles
Falk and Kasha ( 1981 ) found 15 wheats with high crossability with rye among the
56 genotypes tested. Among the 15 wheats exhibiting more than 40 % crossability
with rye, 14 can be traced directly or indirectly to cv. Chinese Spring or to an Asiatic
origin. Songlen, Mendos and 79-72S can be traced back to Chinese Spring through
CI 12632, and Zaragosa 75 through Mengavi. CI 12632 and CI 12633 were derived
from a cross between Chinese Spring and Triticum timopheevii. Salmon reverted to
wheat from a triticale which had Chinese Spring in the wheat parentage. Norin 29
ori ginated from Japan and Peking 10 from China. The other lines tested, with the
exception of Chancellor, can be traced back to crosses involving Chinese Spring.
Riley and Chapman ( 1967 ) hypothesized that Central Asia was a wheat origin area
where rye was not generally grown and would not have been an admixture in culti-
vated wheats. Therefore, there would have been no selection pressure for mutations
of kr to Kr in wheat to prevent pollination by rye. While wheats from this area may
exhibit crossability, not all wheats of Chinese origin are highly crossable with rye,
4 The Crossability of Wheat with Rye and Other Related Species