Successful transferring of male sterility from globe artichoke into cultivated cardoon

Abstract

In the cultivated forms of the genus Cynara, genetic male sterility was recorded only in globe artichoke (var. scolymus). Depending on the plant material used, its inheritance is controlled by up to three independent loci (ms1ms1ms2ms2ms3ms3), where the male sterile (MS) plants are recessive for all loci involved. In order to access the effect of these loci in a var. altilis background, a backcross scheme was conducted along two generations. The donor plant of the MS was a segregant selfed from the genetic composite (MS×'Reri') × ('Cada'×'Riga'). The var. altilis used as recurrent parent was the 'Blanc Ameliore' Semence seeds population. In segregating population, plants were field established and prior anthesis, at least three capitula per plant were covered with pollination bags in order to avoid pollen removal by pollinators. Screenings for pollen production were conducted daily along flowering, except in rainy days. Plants were recorded as male fertile (MF) or MS, when absolutely no pollen shed was observed. F1 plants (12) were all MF. The F2 generation presented 81 MF and 4 MS plants, fitting a 15:1 ratio of two loci segregation (χ2=0.3; p=0.6-0.55). Two backcrossed were advanced, and in the selfed BC2 population 87 MF and 6 MS plants were counted, matching the expected 15:1 ratio (χ2=0.006; p=0.95-0.9). We concluded that the male sterile attribute can be successfully transferred into the cultivated cardoon. This will pave the way for the production of hybrids, not only between var. altilis counterparts, but also among different botanical varieties as well, in order to exploit the vigorous heterotic biomass growth for industrial purposes.