Onion variety and season interaction for yield, storage and disease-insect dynamics under North- east Indian agro-climatic conditions

Aim: An experiments was conducted to investigate the performance of onion varieties in different growing season under agro-climatic conditions of North- east Indian state Tripura. Methodology: Twenty onion varieties were evaluated in rabi, late kharif and kharif. Observations on the plant growth, yield, disease severity, thrips dynamics and storage loss were recorded. The experiments were laid out in a factorial randomized block design. Results: The varieties Bhima Shakti (289.2 q ha-1), Bhima Kiran (288.1 q ha-1) and Bhima Super (284.1 q ha-1) gave higher yield in rabi. season whereas, varieties Bhima Super (292.6 q ha-1) and Sukhsagar (291.9 q ha-1) performed better in late kharif. Severity (PDI) of purple blotch was higher in kharif (26.9) and Stemphylium blight in rabi (27.3) and late kharif (23.9). Thrips population was higher during January to March. Storage loss was less in the varieties Bhima Shakti, Bhima Super, Bhima Kiran, Bhima Shweta, Arka Kirthiman, Sukhsagar and Balwan. Interpretation: A strong interaction effect of onion varieties and growing seasons (kharif, late kharif and rabi) was observed in the present investigation in terms of plant growth, bulb maturity, yield, and incidence of diseases and thrips. Under north east Indian mild tropical agro-climate conditions, varieties Bhima Super and Sukhsagar in late kharif and varieties Bhima Shakti, Bhima Kiran and Bhima Super in rabi season were the most suitable, and may be popularized for cultivation in this region. Key words: Onion agroclimatic condition, Rabi-kharif onion, Thrips dynamics