Variazioni del paesaggio agricolo italiano in relazione all'evoluzione delle tecniche agronomiche

Abstract

Variation of the Italian agricultural landscape in relation to the evolution of the agronomic techniques.- The agricultural activity and the practices that are connected with it more or less directly, have been transformed during the history of mankind according to the evolution of the various societies and policies. These variations are with no doubt the most “responsible” of the evolution of the agricultural landscape. The agronomic techniques that were used in the ancient agricultural societies were initially rough, the land being used temporarly by nomadic people and then abandoned when fertility or weather were not favourable to crop growth and replaced with new fertile areas. Therefore the impact of ancient agriculture on the landscape was very limited, also because of the low population density.

The permanent agriculture developed with the beginning of the great civilisations when the rural environment begun to assume a more stable aspect. During the Reinassance the diversification of agricultural activities had beneficial effects on the landscape, that used to be very variable, both as a result of the mixed cropping systems and the multiple agronomic techniqies used.

The most important upsetting of the agricultural landscape occurred in the last century, when agriculture become an economic activity, with the same dignity of the other productive sectors and related advantages and disadvantages. In this paper the impact of the main aspects of agricultural activity on the agricultural landscape are analysed, with particular attention to the choices that farmers had to make about crops, livestock and management of the rural landscape.     

Somatic embryogenesis in Canary Island date palm

Shoot regeneration was obtained from leaves of in vitro cultures of wild pear genotypes. The highest regeneration rates, ranging from 40% to 64%, depending on the genotype, were obtained using leaves wounded by three cuts transversely to the mid-rib, a Quoirin and Lepoivre macro-salt composition, 250 mg l^-1 cefotaxime and maintaining the explants in darkness for the first 30 days (induction phase), then transferring them to an auxin-free medium in light (expression phase). A concentration of 8.8 μM BA induced the highest number of explants to produce adventitious shoots. TDZ was less effective than BA and induced hyperhydricity in regenerated shoots. The histological studies revealed that the regenerated shoots originated mainly from callus formed by epidermal and sub-epidermal cells and by cells of the vascular tissue. The regenerated shoots were micropropagated, rooted and transplanted to the soil. This revised version was published online in June 2006 with corrections to the Cover Date.