Pollination studies in large cardamom (Amomum subulatum Roxb.) of Sikkim Himalayan region of India

Pollination studies in large cardamom were carried out at the research farm of ICAR Sikkim Centre, Gangtok, Sikkim, India during 2009–2010 to assess the effectiveness and efficiency of pollinators. Polleniferous flowers (65,890 ± 11,346.5 pollen/anther) of large cardamom produce spherical, large (108.64 μm × 96.32 μm) and echinate pollen with high pollen/ovule ratio (585.2 ± 134.8). Native bumblebee (Bombus braviceps Smith.), a nectar forager, was identified as the most effective pollinator in terms of pollination potential index score (0.88), pollen removal (55.39%) and deposition rate (4.5%), pollination efficiency and pollen delivery mechanism whereas honey bee acted as a pollen robber. Flowers appeared to be generalized; however, functional specialization was exhibited indicating that only bumblebee is adaptable for pollination moreover, pollination mechanism was an indicative of “pollination syndrome”.     

Influence of growth conditions on yield,quality and diseases of strawberry (Fragaria x ananassa Duch.) var Ofra and Chandler under mid hills of Sikkim Himalaya

Field experiments were conducted during 2005–09 at ICAR Sikkim Centre, Tadong, East Sikkim, India at an altitude of 1400 m amsl to identify the suitable environment for high production of good quality fruits with less diseases for strawberry varieties Ofra and Chandler. Both the varieties were grown under low cost polyhouse, plastic tunnel and open conditions. Maximum number of flower trusses per plant was recorded in Chandler under open condition (13.0) followed by plastic tunnel (12.7). The maximum number of fruits per inflorescence was found in Ofra (7.12) under polyhouse while maximum number of runners per plant was observed in Ofra (12.3) in open conditions. Plastic tunnel with Ofra produced highest fruit weight (26.2 g), fruit length (5.5 cm) and fruit diameter (3.9 cm). Best fruit quality in terms of TSS (6.8%), lower acidity (0.83%) and total sugar (6.3%) was observed in Chandler under plastic tunnel conditions. The highest total fruit yield was recorded with Ofra under plastic tunnel (40.2 t/ha) but the maximum marketable yield was obtained in Chandler under plastic tunnel (35.3 t/ha). Diseases were found to be less prevalent in tunnel as compared to polyhouse and open conditions.