C. Bignami

Accurate and Rapid Technique for Leaf Area Measurement in Medlar (Mespilus germanica L.)

Accurate measurements of leaf area are important for agronomic and physiological studies. Deter- mining the individual leaf area (A) of medlar (Mespilus germanica L.) involves measurements of leaf parameters, such as length (L) and width (W), or some combinations of these parameters. A two-year investigation was car - ried out in 2005 (on seven genotypes) and in 2006 (on one cultivar) underopen-field conditions to test whether a model could be developed to estimate leaf area across genotypes. Regression analyses of A versus Land W revea- led several models could be used for estimating the area of individual medlar leaves. A linear model having LW as the independent variable (A = 1.81 + 0.68 LW) provided the most accurate estimate (R 2 = 0.981, MSE = 7) of medlar leaf area. Validation of the model having LW of leaves from another genotype measured in the 2006 expe- riment showed that the correlation between calculated and measured areas was very high. Using the selected model, agronomists and physiologists can accurately and reliably estimate the leaf area of medlarwithout the use of expensive instruments.

Influence of Bunch Position in the Canopy on Berry Epicuticular Wax during Ripening and on Weight Loss during Postharvest Dehydration

Passito wine, made with dehydrated grapes, is widespread in Italy. The quality of the grapes to be withered is strongly influenced by qualitative factors and the anatomy and morphology of the berry, which in turn, are affected by vineyard management and microclimate. In Trebbiano toscano and Rossetto vines grown in the Latium region, the epicuticular wax of berries from bunches developed in intracanopy and extracanopy positions was analyzed from preveraison to preharvest during the 2007 and 2008 growing seasons. At harvest, the characteristics of cuticle and epidermis of each sample were examined using light and electron microscopy. The berries were then dehydrated at 20°C to 45% moisture to evaluate differences in water loss rate and the mechanical characteristics of the skin. The amount of epicuticular wax decreased during berry development. SEM observations of the berry skin at harvest showed differences in the structure of the epicuticular wax layers, with a wider berry surface covered with plate-like wax in extracanopy berries. The number of cell layers and the thickness of the berry skin were significantly different between cultivars and canopy positions, but these factors did not affect cuticle thickness. Shaded berries of both varieties dehydrated more slowly, particularly in vigorous Trebbiano toscano vines, in which intracanopy berries reached 40% weight loss later than the extracanopy berries. During dehydration, the berry skin color (hue angle) decreased and berries of both varieties increased skin resistance to puncturing; this was not affected by the position of the berry in the canopy.

Aromatic Characterisation of Malvasia Odorosissima Grapevines and Comparison with Malvasia di Candia Aromatica

Malvasia odorosissima is an aromatic grapevine (Vitis vinifera L., 1753) variety that is often confused with Malvasia di Candia aromatica (Vitis vinifera L., 1753), despite the genetic information now available on the pedigree and genetic relationships linking the two varieties. In an effort to offer a contribution to fill this gap, also from an aromatic point of view, free and glycosylated aroma compounds were determined using the SPE extraction method, followed by GC-MS analysis in two consecutive vintages. The results have for the first time provided the aromatic characterisation of Malvasia odorosissima. Geraniol and its derivatives were the most abundant set of volatiles. In contrast to Malvasia di Candia aromatica and the other aromatic varieties, Malvasia odorosissima showed a very small amount of glycosylated volatiles, thus expressing its aromatic potential almost completely. The abundance of free terpenoids in the aromatic profile of Malvasia odorosissima, even higher than in Malvasia di Candia aromatica, is a main feature for the oenological exploitation of this variety, which is on the brink of extinction. In addition, the presence of rose oxides, found solely in Malvasia odorosissima, renders its aromatic profile more similar to that of White Muscat. This result is consistent with the parent-offspring relationship linking the two varieties that was recently ascertained.