TY  - BOOK
AU  - Swapna S 
AU  - Rajeevan P K (Guide)
TI  - Regulation of growth and flowering in Dendrobium Var. Sonia 17
U1  - 634.1 
PY  - 2000///
CY  - Vellanikkara
PB  - Department of Pomology and Floriculture, College of Horticultutre
N2  - Studies on 'Regulation of growth and flowering m dendrobium var. 
,. 
'Sonia 1 T were conducted in the Department ofPomology and Floriculture, College of 
Horticulture, Vellanikkara from June 1998 to November 1999 and at Padikkala 
Orchids, Thrissur from February to September 1999. The main objectives of the studies 
were to reduce the pre-blooming period, to improve the yield and quality and to 
	, 	..... 
enhance the post harvest life of spikes using various treatments. 
Plant height was significantly superior (19.50 cm at 10 MAP) with the 
combination of NPK 30: 10: 10 at 0.2 per cent, applied weekly twice + GAJ 20 ppm. 
With respect to number of shoots, NPK 30: 10: 1 0 at 0.2 per cent, applied weekly twice 
+ BA 200 ppm was most effective (with 7.67 shoots). Shoot girth recorded maximum 
value (5.80 cm) at 10 MAP in the treatment combination ofNPK 30:10:10 at 0.2 per 
cent, applied weekly twice + IAA 500 ppm. 
Plants which received NPK 30: 10: 10 at 0.2 per cent weekly twice along 
with BA 200 ppm recorded maximum leaf production (19.83 leaves at 10 MAP). In 
the case of total leaf area, BA 200 ppm produced maximum value (210.12 ~2) in 
combination with NPK 30: 10: 10 at 0.2 per cent, applied weekly twice. Number of 
roots was markedly higher for NPK 30: 10: 10 at 0.2 per cent weekly twice with BA 
200 ppm, which produced 42.0 roots. 
Biomass production (dry weight) was the highest (6.94 g/plant) for NPK 
30: 10: 10 at 0.2 per cent, applied weekly twice + BA 200 ppm. The combination of 
NPK 30: 1 0: 1 0 at 0.2 per cent, applied weekly twice + lAA 250 ppm recorded the 
highest nitrogen content of 2.4 7 per cent. This was on par with BA 200 ppm, IAA 50 
ppm and BA 100 ppm in combination with the same level of nutrients. Maximum 
value for P content (0.6~1o) was observed in the combination ofNPK 30:10:10 at 0.2 
per cent, sprayed weekly twice + IAA 500 ppm. The growth regulator component was 
on par with lAA 250 ppm. The combination which yielded highest value for K content 
 

 
 

(4.00%) was NPK 30: 10: 10 at 0.2 per cent, applied weekly twice + IAA 250 ppm. The 
same level of nutrients with IAA 500 ppm was on par with this. 
The contents of Ca and Mg were higher with higher nitrogen levels and 
frequencies, coupled with BA 200 ppmIfor Ca) or IAA 250 ppm (for Mg) .. In the case 
of micro-nutrients (Cu, Fe, Zn and Mn), lower levels of nitrogen at higher frequencies, 
in combination with IAA 500 ppm, recorded higher values. 
Uptake of N,. P, and K was the highest with the combination of. NPK 
30:10:10 at 0.2 per cent, applied weekly twice + BA 200 ppm (1l.73 g, 2.7~ g and 
19.50 g, respectively). Uptake ofP was on par for lAA 500 ppm, with the above level 
of nutrients. 
Earliest flowering (300 DAP) was recorded in plants which received a 
treatment combination of NPK 30: 1 0: 1 0 at 0.2 per cent, applied weekly twice + BA 
200 ppm .. Plants receiving the nutrient level of NPK 20: 10: lOin the above 
combination flowered next (308 DAP). 
Nutrients, their frequency C?! application and .. growth regulators markedly 
influenced flower yield and quality. A combination of NPK 10:20: 1 0 at 0.2 per cent, 
applied weekly twice + BA 100 PP!ll recorded. the maximum number of spikes :Q~r year 
(12.98) and number of florets per spike (10.50). Spike length was significantly superior 
(55.40 cm) for NPK 10:20:20 at 0.2 percent, applied weekly twice + GA3 20. ppm. 
Longest stalks (30.10 cm) were produced at the same level of nutrients, coupled with 
BA 100 ppm. A treatment combination of NPK 10:20: 10 at 0.2 per cent applied 
weekly twice + (BA 50 ppm + GAJ 10 ppm) produced the longest rachis (30.25 cm), 
which was on par (30.16 cm) with the above nutrients applied weekly once + GAJ 20 
ppm. Intemodallength was the highest (5.14 cm) in the combination ofNPK 10:20:10 
at 0.2 p~r cent, applied weekly once + GAJ 20 ppm. Girth of spike was. maximum 
(2.95 cm) with NPK 10:20: 1 0 at 0.2 per cent, applied weekly twice + BA 100 ppm. 
 
, 
 

The interval of spike production was the least (28.12 days) for NPK 
10:20: 1 0 at 0.2 per cent, applied weekly twice + BA 100 ppm. Floret size was reduced 
to 6.0 cm x 6.0 cm by- the treatment combinations NPK 10: 10: 10 at O. 1 per cent 
(weekly once or twice) or 0.2 per cent (weekly once) + BA 100 ppm. Largest floret 
	. . . 	, 
size of8.0 cm x 8.5 cm was observed in plants receiving NPK 10:20:10 at 0.1 or 0.2 
per cent, applied weekly twice + GA3 20 ppm. 
Various pulsing and holding treatments and their combinations significantly 
influenced the post. harvest behaviour of spikes. Among. the pulsing . treatments, 
minimum loss of weight (0.93 g) of spikes was recorded when kept in HQ 500 ppm + 
sucrose 5 per cent for 6 hours. Spikes took the 101:1ges~ time (19.92 days) for the ~ilting 
of one floret (vase life) when pulsed with HQ 500 ppm + suctose 5 per cent for 12 
hours. Final BC (2.13 mS il) and water uptake (19.99 ml) were the highest in hot 
water dip treatment at 50°-60°C for 10 seconds. Days to wilt of the last floret was the 
highest (25.00 days) when treated with HQ 500 ppm + sucrose 5 per cent for 12 hours. 
Minimum loss of weight of spike (0.13 g), maximum days to wilt of the last 
floret (30.50 days) and maximum vase life of spike (24.73 days) were recorded by the 
holding treatment containing AgN03 50 ppm + HQ 400 ppm + sucrose 5 per cent. 
Maximum BC (3.75 mS g-l) was recorded for Triadimefon 20 ppm. Difference 
between initial and final BC was maximum (0.11 mS g-l) for AgN03 50 ppm + HQ 
400 ppm + sucrose 5 per cent. Water uptake was highest (19.50 ml) in AgN03 25 ppm 
+ sucrose 5 per cent. 
Pulsing and holding treatments, in combination, gave significant differences 
ill post harvest characters. Minimum weight loss (0.07 g) was observed when 
pulsed with HQ 500 ppm + sucrose 5 per cent for 12 hours and kept in the holding 
solution containing AgN03 5Q ppm + HQ 400 ppm + sucrose 5 per cent. Final EC 
(0.28 IllS g-l) of holding solution was the highest for the combination of pulsing 
treatment of• HQ 500 ppm + sucrose 5 per cent for 12 hours and holding treatment of 
 
quality more treatments with combinations of GA3 and BA can be studied. The results 
of the experiment can also be extended to find effects on other important varieties of 
dendrobium as well as other genera. The results of experiment I and experiment II 
have to be tried to the same lot of plants to find the combined effect. 


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