Screening of different morphotypes of colocasia for shade tolerance

Abstract

The present study 'Screening of different morphotypes of colocasia for shade tolerance' was conducted during May 1989 to June 1990 at the College of Horticulture, Vellanikkara , Thrissur, Kerala, India . The experiment was laid out in a split plot design with four replications. Eleven morphotypes of colocasia were raised at shade levels of about 0, 25, 50 and 75 per cent. For providing shade, pandals were erected on wooden frames and covered with unplaited coconut fronds to provide required levels of shade. These were covered on all sides also leaving a clearance of 1 m from ground level. L I -190 SA Quantum Sensor and LI-191 SA Line Quantum Sensor were used for adjusting the shade intensities approximately to the desired levels. Most of the colocasia morphotypes recorded the highest yield at 25 per cent shade and hence this crop is to be classed as shade loving. However there were substantial differences in varietal responses to shade and in the morphotypes M1 , M7, M8, M9 , M10, M12 and Sree Rashmi yields were higher under shaded condition than in the open. In M2, M15, M16 and M17 yields were higher in the open and there was steady decline with increasing shade intensity. Harvest index and drymatter accumulation were found to be the highest under 25 per cent shade level in most of the morphotypes. But the highest starch and oxalic acid contents were in the tubers from the open. Six morphotypes M1, M2, M10, M15, M16 and M17 were selected as generally superior for all shade situations.