Variations in Yield and Nutritional Profile of Onion Germplasm under the Influence of Purple Blotch Disease

Purple blotch of onion caused by Alternaria porri (Ellis) Cifferi.induces paramount losses in different parts of the world.In the present study, potential of 25 onion genotypes was evaluated against purple blotch and their yield response during two years (2014-15) under field conditions.Selected onion genotypes were also evaluated for the mineral and proximate parameters.Five varieties (Phulkara, Sunset, Ceylon, TI-172, XP-Red) showed resistant response while Desi Red, Early Red, Robina, Dark Red and Mirpurkhas exhibited moderately resistant response.VRIO-6, VRIO-1, VRIO-4, Red Nasik and Desi Black were found moderately susceptible against the disease.VRIO-9, Pak-10321, Fsd Red, Pusa Red and Red Imposta gave susceptible response, while VRIO-3, VRIO-5, VRIO-8, VRIO-7 and VRIO-2 exhibited highly susceptible response.Phulkara exhibited maximum yield followed by other tested varieties whereas minimum yield was recorded in case of VRIO-2.Regarding the mineral and proximate analysis, leaf of purple blotch susceptible variety (VRIO-2) exhibited lower quantity of fiber, crude protein, ash and fat as compared to Phulkara leaves.Carbohydrate and moisture contents in Phulkara (resistant variety) leaves were lower as compared to VRIO-2 leaves.Mineral contents in VRIO-2 leaves were lower as compared to Phulkara leaves.Mineral contents increased in resistant (Phulkara) leaves and decreased in susceptible (VRIO-2) leaves during 2 nd year.However proximate contents increased in both resistant and susceptible leaves during 2 nd year.It was concluded that Phulkara exhibited resistance against purple blotch as compared to other varieties with greater yield and mineral contents.