Ongoing Research work.
Photoperiodic control of flowering
1. Flowering is induced in non-flowering types. The treatment being:
Inductive photoperiod-12:30hrs-12:45hrs.
Temperature -23C
Relative humidity -80%
with an inductive cycles of 30-60.
2.Delay of flowering:
Night break by light treatment (12.00-2.00hrs)
Leaf trimming.
Physiology of sugarcane under drought.
Sugarcane yield reductions were significant under drought. The yield loss depends on the intensity of stress and the resistance
nature of the genotype.
A resistant type maintains the green leaves with leaf rolling feature
A drought resistant type in the field
While a susceptible type shows severe drying of leaves.
Sugarcane and Salinity
Germination of sugarcane setts in saline soil:
Soil salinity has a
profound impact on the crop growth specially so with the process of germination. Germination was delayed under salt treatment
and reduction in final germination percent was observed at higher salinity level (EC >5dS,m-1).
Higher reduction in germination of setts with increasing salinity levels were reported for sugarcane. Varieties showed significant
difference in germination . Kumar and Naidu, (1997) observed that soil salinity as more damaging for germination
of setts at low temperature (below 25º C). Reduction in germination percent is used as one of the criteria for rating
the varieties for salinity tolerance. Varietal response is a critical factor in determining the final germinant. For instance
genotypes like Co 97010, Co 95007 etc recorded a reduction in germination % over 50 indicating their sensitiveness.
Tillering and early growth: Tiller produced per main shoot also decreased under
salt treatment. In a study with 10 popular varieties, the reduction in tiller production due to salt treatment was be
from 16.3 ( Co 6304)to 49.8% (Co 86010). Consequently, shoot population was also reduced resulting in poor and patchy field
stand. Shoot height, number of internodes, number of leaves and leaf area per plant were significantly less in saline soil.
Decreased or nil expansion growth of leaves and young internodes results in stunted canopy and poor tillering results in poor
crop. Apart from tillering cane formation was inhibited and the internodes were very narrow suggesting the sensitivity of
expansion growth.
Physiological and metabolic behaviour under salinity.
The crop in an attempt
to equilibrate with the osmotic potential of soil water increase the absorption of water along with the salts resulting in
higher salt accumulation in the plants. In response to the osmotic stress specific osmolytes are accumulated in vacuoles.
Osmotic potential of the leaf tissues increased by 50 to 200m.mole,Kg-1 in salt treatment as compared to normal
plants. Proline is one among the widely studied osmolyte that accumulate in response to stress conditions. In popular varieties
several fold increase in proline content was observed
Cell membrane stability
is a measure to test the membranes biophysical /biochemical properties. Under stress situation the cell membrane looses the
selectivity of ions and macromolecules resulting in heavy influx/efflux of essential ions in and out of cells. A resistant
genotype maintains the cell membrane properties so also the selectivity of molecular movement and maintains growth and metabolism.
Cell membrane injury test conducted with popular varieties showed significant variation indicating their tolerance capacity
(Fig2).
Yield and quality characters as influenced by salinity.
Reduction in number
of millable canes was upto 37% in popular genotypes and tolerant genotypes recorded less reduction. Cane length, girth, number
of internodes showed reduction due to salt treatment, which ultimately reduced the cane weight and yield. Nour et.al (1989)
reported a decrease in cane yield of the order of 5.45t/h for every 1m.mohs/ha (from an Electrical conductivity of 5m.mohs).
Yield reduction from 20%(Co 86011)to 45%(Co 7219) has been recorded in popular genotypes.
Sucrose% juice, brix and purity reduced due to salinity.
Increased non-sugar solids and salts reduce the purity. Reduction in sucrose % juice is used as a criterion for rating the
genotypes for their tolerance to salinity. The salt content of cane juice ranges from 900-1900 pip in non-saline soils and
from 4000-4500ppm in saline soils. Salt treatment adversely affected jaggery quality also. Increase in moisture and fibre
content of the jaggery was observed in salt treatment. Overall quality of the jaggery dropped from A1 grade to B grade. However
some varieties do perform well in maintaining the jaggery quality. Genotypes Co 86033, Co 86027 and Co 86018 retained A1 grade
quality jaggery even under salt treatment.
Co95007 a sensitive type
Co 85019 a tolerant type
Co 94012 a tolerant type
Co 97010 a sensitive type
