Effect of Fruit Rot [Alternaria alternata (Fr.) Keissler] Disease on Biochemical Parameters in Chilli Varieties with Different Levels of Resistance

Fruit rot caused by Alternaria alternata is a major constraint in chilli causing several losses in terms of quality and quantity. The biochemical variation in chlorophyll, capsaicin and ascorbic acid content were estimated from six chilli varieties representing resistant (GVC-131, GVHC-1), moderately resistant (GVC-112, GVC-121) and susceptible (GVC-101, GVC-111) reaction from diseased (Alternaria fruit rot) and healthy fruits at semi ripe stage, when the disease was severe (more than 40%) in the field. The resistant (GVC-131 and GVHC-1) and moderately resistant (GVC-112 and GVC-121) varieties recorded higher amounts of chlorophyll, capsaicin and ascorbic acid content than susceptible varieties (GVC-101 and GVC-111) in both healthy and diseased fruits. The percent decrease in total chlorophyll was least (49.96%) in GVC-131 and GVHC-1 (both resistant), followed by 59.41 per cent in GVC-112 and GVC-121 (both moderately resistant), whereas, highest decrease of 77.28 per centin GVC-101 and GVC-111 (both susceptible). The chlorophyll ‘a ’and ‘b ’were also reduced in the same trend at higher rates in susceptible varieties because total chlorophyll was cumulative of chlorophyll ‘a ’and ‘b'. In case of capsaicin, the least rate of decrease in diseased fruits was 40.59 per cent in GVC-131 and GVHC-1 (both resistant) followed by 60.82 per cent in GVC-112 and GVC-121 (both moderately resistant), whereas highest percent decrease of 69.07 in susceptible (GVC-101 and GVC-111) varieties. For Ascorbic acid, the least rate of decrease in ascorbic acid content in diseased fruits was 42.67 per cent in GVC-131 and GVHC-1 (both resistant) followed by 58.48 per cent in GVC-112 and GVC-121 (both moderately resistant), whereas highest percent decrease of 71.77 in susceptible (GVC-101 and GVC-111) varieties.