Genetic control of crossability of triticale with rye

Limited genetic knowledge is available regarding crossability between hexaploid triticale (2n = 6x = 42, 21 ", AABBRR, amphiploid Triticum turgidum L.-Secale cereale L.) and rye (2n = 14. 7 ", RR). Our objectives were to determine (1) the crossability between triticales and rye and (2) the inheritance of crossability between F-2 progeny from intertriticale crosses and rye. First, '8F/Corgo', a hexaploid triticale, was crossed as a female with two landrace ryes, 'Gimonde' and, 'Vila Pouca' and two derived north European cultivars, 'Pluto' and 'Breno'. These crosses produced 21.7, 20.9, 5.9, and 5.6%, seed-set or crossability, respectively, showing that the landrace ryes produced higher seed-set than the cultivars. Second, 'Gimonde' rye was crossed as a male with four triticales for 3 years. The control cross, 'Chinese Spring' wheat x rye, produced 80-90% seed-set. Of the four triticales, 'Beagle' produced 35.7-56.8% seed-set. The other three triticales produced less than 20% seed-set, showing that the triticales differ in crossability with 'Gimonde' rye. Third, six F(1)s from intertriticale crosses ('8F/Corgo' x 'Beagle', 'Beagle' x 'Cachirulo', 'Lasko' x 'Beagle', '8F/Corgo' x 'Cachirulo', 'Lasko' x 'Cachirulo', 'Lasko' x '8F/Corgo') were crossed to 'Gimonde' rye. Results indicated that lower crossability trait was partially dominant in the two F(1)s from crosses involving 'Beagle' (high crossability) with '8F/Corgo' and 'Cachirulo' (low crossability) and completely dominant in the 'Beagle' x 'Lasko' cross, as it happens in wheat. Fourth, segregants in four F-2 populations ('Lasko' x 'Beagle', '8F/Corgo' x 'Beagle', 'Lasko' x '8F/Corgo', and '8F/Corgo' x 'Cachirulo') were crossed with rye. Segregation for crossability was observed, although distinct segregation classes were blurred by environmental and perhaps other factors, such as self-incompatibility alleles in rye. Segregation patterns showed that 'Beagle', with high crossability to rye, carries either Kr1 or Kr2. The three triticales with low crossability with rye were most likely homozygous for Kr1 and Kr2. Therefore, it is likely that the Kr loci from A and B genomes acting in wheat also play a role in triticale x rye crosses.