COMPARATIVE-STUDY OF THE THERMOLUMINESCENCE GLOW CURVES RECORDED FROMVARIETIES OF VITIS-VINIFERA, V-LABRUSCA AND V-CHAMPINI

Thermoluminescence (TL) glow curves were recorded from leaves of eight Vitis varieties grown in South-West India, viz. Thompson Seedless, So naka, Anab-E-Shahi, Kishmish Charni, Tas-A-Ganesh, Black Monuka, Banga lore Purple and American Dogridge belonging to the Vitis vinifera, V. labrusca and V. champini species. The TL peaks were analysed, using a computer-assisted model based on the general order kinetics theory, to determine thermodynamical parameters such as activation energy, entro py, frequency factor and free energy. It was observed that all six V. vinifera samples showed an entirely different TL pattern consisting of only one prominent and highly narrow peak at around -5 degrees C (pea k II). The prominence of this peak attributed to S-2/S-3 Q(a)(-) recom bination suggests a modification at the plastoquinone electron accepto r sites. On the other hand, the remaining two varieties Bangalore Purp le and American Dogridge showed broader TL spectra consisting of a hig her number of peaks. This basic difference is attributed to the differ ence in species of the selected varieties. Moreover, the TL recorded f rom Bangalore Purple resembled the standard TL spectra of spinach. The study undertaken in this paper may be relevant in grape breeding prog rams.