National Symposium on “Plant Pathology in the Changing Global Scenario” held at National Bureau of Plant Genetic Resources, New Delhi on February 27–28, 2009
Seedlings of marigold cv. ‘Pusa Narangi’ were transplanted in the field on October 1st in 2.4 m2 plots at different spacings, i.e. 30x30, 30x40, 40x40, 30x60, 40 x40, 40x60 and 60x 60 cm, using randomized block design, replicated thrice The per cent intensity of leaf spot (Alternaria tagetica) was found to be 59.2, 58.3, 53.3, 50.8, 47.5 and 43.3, respectively at these spacings, indicating that closer spacings favoured disease development more than wider spacings. Number and weight of healthy flowers produced was, nearly 3–4 times more at the lowest spacing (30x30 cm) as compared to that at the highest spacing (60x60 cm), thus showing better returns per unit area at the lowest spacing. As the yield was not compensated at wider spacings, contrary to what was hypothesized, it is advisable to grow marigold plants at a spacing of 30x30 or 30x40 cm and adopt some disease management practice. Furthermore, the spacing needs to be worked out for each variety separately as the spread could vary from variety to variety. Apart from this the edaphic and environmental factors shall also influence the spread, in other words the yield, which also need to be taken into count.
