Joseph Louis

Photosynthetic Efficiency, growth, yield and quality of Turmeric (Curcuma Longa L.) under Different shade levels - Vellayani Department of Horticulture, College of Agriculture 2000



A field experiment was conducted at the College of Agriculture,
Vellayani during the period from 1998-' 99 to study the effect of shade
on photosynthetic efficiency, partitioning of photosynthates and quality
of turmeric (Curcuma longa L.) under different shade levels. The
experiment was laid out as split plot design with shade levels of 0, 25,
50 and 75 per cent as main plot treatments and 3 varieties, Kanthi,
Alleppey and Sobha as sub plot treatments. The number of replications
was four. Artificial shade was provided using high density polyethylene
shade nets and calibrated using quantum photosensors. Bimonthly
observations of various growth parameters were taken from two months
after planting. At s.ix months after planting photosynthetic related
parame!ers were recorded. The various growth parameters like number
of tillers, dry matter production, crop growth rate, bulking rate and harvest
index which contributed to yield was highest under 25 per cent shade.
The yield recorded at 25 per cent shade was significantly superior when
compared to open, indicating the shade tolerance of the crop.
Different shade levels influenced the quality of turmeric rhizomes
as determined by the volatile oil content which was maximum under 75


2
per cent shade level and curcumin content was maximum under 50 per
cent shade level.
The photosynthetic rate and related parameters like leaf
temperature, leaf internal CO2 concentration and stomatal conductance
of' turmeric were measured at 6 MAP using leaf chamber analyser.
Photosynthetically Active Radiation (PAR) on leaf surface, stomatal
conductance, leaf internal CO2 concentration and leaf temperature was
high .under open condition. Photosynthetic rate was maximum in plants
grown at open condition. Though at 25 per cent shade, the photosynthetic
rate was less, the yield was high at this shade level when compared to the
open condition. Under open condition there is a possibility of an increase
in photo-oxi dation I photo-respiration resulting in the inefficient
translocation of photosynthates from the source to the sink.
The results indicate that low levels of shade is favourable for
growing turmeric to get high rhizome yield and this specific nature of
turmeric can be. fully exploited for growing this as an intercrop or as a
crop component in homesteads.



635 / JOS/PH
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