Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 2.05

JANA: A NEW COCKSFOOT VARIETY FOR MEDITERRANEAN ENVIRONMENTS

E. PIANO, M. ROMANI, A.M. CARRONI, L. PECETTI

Istituto Sperimentale per le Colture Foraggere, Lodi

cocksfoot, Dactylis glomerata, drought stress, Mediterranean environment, summer irrigation

In Mediterranean environments, the persistence of perennial grasses, such as cocksfoot (Dactylis glomerata L.), is heavily limited by long periods of drought in summer. The most effective plant strategy of survival is summer dormancy, which represents therefore a main selection criterion for varieties to be grown under rainfed conditions. However, development of varieties able to combine effective summer dormancy under stress with responsiveness to moisture avilability, in case of prolonged rainfall season or when supplementary irrigation in summer is provided, is also required. A new variety has been released by our Institute, which aims at meeting the above-mentioned requirements. This variety, named ‘Jana’, derives from materials singled out within both a wild population collected at Bonorva, Sardinia, and the variety ‘Currie’ of Mediterranean origin. The selection process of Jana was based on two consecutive phases, both contemplating contrasting irrigation treatments in summer: I) a preliminary phenotypic selection; and II) a subsequent selection based on a half-sib progeny test, which narrowed the previously selected plants. In the present investigation, ‘Jana’ was compared with one variety selected from Mediterranean germplasm and known to be summer dormant (‘K2M’), three varieties adapted to temperate conditions (‘Cambria’, ‘Dora’ and ‘Porto’), and the two parental populations (‘Bonorva’ and ‘Currie’). The trial, carried out in south Sardinia, included three consecutive evaluation phases: I) under rainfed conditions from autumn to spring; II) under contrasting moisture conditions in the following summer; and III) under rainfed conditions in the subsequent autumn-spring season to assess the effect of the previous summer treatments. ‘Jana’ showed the highest dry-matter yield under both rainfed conditions and summer irrigation, although not significantly different from the best temperate varieties, while it did outyield significantly ‘Bonorva’ and ‘Currie’ from which it derives, then evidencing a remarkable selection response. Owing to summer dormancy, its survival under the summer stress treatment was close to 90%, whereas all the summer-active, temperate varieties did not survive the drought. However, such a dormancy was facultative, as indicated by the yield response under irrigation. Preventing summer dormancy by irrigation had no detrimental effect on the subsequent regrowth of Mediterranean varieties in autumn-spring. At the same time, the mechanism of drought tolerance also did not affect the subsequent performance of ‘Jana’, as it outyielded significantly all varieties, including the other Mediterranean germplasm, in the autumn-spring period following the summer stress treatment. ‘Jana’ appears therefore to possess the wished feature of combining an effective drought tolerance (summer dormancy) under stressful conditions with an appreciable responsiveness to moisture availability.