Studies on phytoalexins in screening grape germplasm for anthracnose resistance.

Resveratrol content of grape genotypes having graded resistance to anthracnose disease was analyzed in the infected and healthy leaves. The diseased leaves contained significantly higher amount than healthy leaves. The per cent difference was highest in resistant category. The genotypes varied significantly in respect of resveratrol control (26.4 μg/g to 144.3 μg/g). In both the year (1994 and 1995), the genotype categories behaved similarly. The correlation studies revealed high negative correlation (r=0.908 and 0.931 in 1994 and 1995 respectively) of resveratrol with per cent disease index. This showed that selection for this trait is effective. This could be used as an important selection criteria in grape breeding programme for incorporating disease resistance anthracnose.