111from Himachal Pradesh were found to be free of crossability inhibitors, therefore
having the genotype kr1kr1kr2kr2 , as they had more than 50 % crossability with
rye. The other 48 cultivars had low crossability with rye.
The crossability of Hungarian wh eat varie ties was studied in the fi eld in
Martonvásár in two different years by pollinating them with rye (Molnár-Láng and
Sutka 1989 ). Russian, Yugoslav, Rumanian, Czech, Italian, and Austrian wheat
varieties used as crossing partners in Hungarian wheat breeding programmes were
also included in the study. The hybrid nature of the seeds was checked by chromo-
some counting. A total of 33 genotypes were pollinated with rye. The seed set val-
ues of the Chinese Spring, Roazon and Songlen wheat varieties used as controls
agreed with the numbers expected according to relationship between genotype and
the percentage crossability reported by Lein’s ( 1943 ). Among the Martonvásár
wheat varieties the seed set values of Mv9 and Mv13 were 15.4 % and 10 %, respec-
tively, putting them in the 10–30 % group with the Yugoslav variety NS 3000 (10.7
%) and the Rumanian F-29 (12.5 %). These data suggest that the recessive allele
pair kr2kr2 may have been introduc ed into Hungarian varieties via Soviet and
Yugoslav genotypes.
4.4 Transfer of Crossability Alleles into European Wheat
Varieties
A highly crossable winter wheat genotype, Martonvásári 9 kr1 (Mv9 kr1), was
developed in Martonvásár by Molnár-Láng et al. ( 1996 ). The crossability of the
initial wheat cultivar Martonvásári 9 (Mv9) was studied by pollinating with rye in
seven different years together with the control wheat cv. Chinese Spring (CS). The
maximum seed set of Mv9 with weed rye was 15.4 % in 1 year, but in the following
years it never exceeded 5 % when pollinated with rye. The Mv 9 variety possessed
dominant Kr1Kr1 alleles and was heterogeneous at the kr2 locus, so that some
individual plants carried recessive kr2 alleles. Mv 9 was crossed with CS in 1985
and the F 1 hybrid was backcrossed with Mv9 in 1986. Plants possessing the reces-
sive kr alleles were selected from the (Mv9 × CS) Mv9 BC 1 generation according to
the seed set achieved when pollinated with rye. The partial dominance of the kr
alleles made it possible to differentiate between plants heterozygous at the Kr1
locus and the dominant homozygous Kr1Kr1 plants. Progenies in two consecutive
selfed generations were tested by pollination with rye to select homozygous reces-
sive kr1kr1kr2kr2 plants and to check the result of selection after each backcross
(Fig. 4.1 ).
As a result of three backcrosses with Mv9 and two selfi ngs after each backcross
the selected progenies had 61.6 % seed set with rye when tested on 60 individual
plants. These data confi rmed that after the third backcros s the selected Mv9 kr1 line
carried recessive crossability alleles kr1 and kr2 , but the genotype was 93.75 %
Mv9 (Molnár-Láng et al. 1996 ). After the sixth backcross and two selfi ngs the CS
4 The Crossability of Wheat with Rye and Other Related Species