Abstract
Investigations were carried out to standardize suitable concentration and combination of
growth regulators for in vitro callus induction and plantlet regeneration potentiality of six
potato varieties, plantlet development and multiplication, virus indexing and virus
elimination for quality seed potato production, potato microtuber production, their field
performance were evaluated. Agrobacterium mediated genetic transformation of salinity
and drought tolerant genes were performed. The experiments were conducted mainly to
improve seed quality of potato through biotechnological approach. Different concentration
and combinations of growth regulators were used in MS medium to observe the callus
induction ability using leaf and internodal segment of in vitro plantlet as explant. The
internodal segments derived from in vitro potato plantlet exhibited better performance for
callus initiation within a shortest period of time on MS medium supplemented with the
growth regulator combination of 2.25 mg L¹ BAP and 2.50 mg L¹ NAA. NAA or BAP
alone showed low callusing response in potato explants, while they together induced more
calli. The maximum (101.33) number of days required for regenerated shoot initiation was
in Lalpakri with 2.0 mg L¹ BAP and the lowest (56.42) number of days required for
regeneration of shoot was found in variety Heera with 6.0 mg L-¹ BAP. The maximum
(12.35 cm) height of regenerated potato plantlet was in Heera variety with 6.0 mg L BAP
at 90 DAC. The highest (57.02) percentage of regenerated plantlet was produced from
variety Heera with 6.0 mg L¹ BAP. The growth of root and shoot of in vitro plantlet, MS
medium supplemented with 0.04 mg L'NAA proved the best. A wide variation on success
of obtaining in vitro plantlet through meristem culture was observed at different treatment
combinations. The control (27±1)°C showed better results than the other two treatments
(30+1)°C and (35±1)°C in which the meristems were given heat treatment after excision.
Four days of preculture plus four days of co-cultivation was the best for recovery of
transgenic shoot. Callusing percentage ranged from 71.72 to 67.19. The highest (71.72)
callusing percentage of Agrobacterium inoculated explants was found in preculture + cocultivation period of (0+2) days. During transformation of gly I three day period of
preculture and co-cultivation was the best for recovery of transgenic shoot. Internodal
segment of Heera showed highest (50.03) transformation ability. Transgenic plantlet in
(6+4) period showed the highest (26.67%) in Heera and Diamant plantlet in (4+4) showed
the lowest (6.93%) survival ability. The maximum (108.10) days required for microtuber
initiation recored in 16h photoperiod in control combination whereas, the minimum (45.22)
days in completely dark period in 200 mg L¹ + 70 g L¹. Higher (7.33) number of
microtuber plantlet was recorded in combination of 200 mg L-¹ CCC and 70 g L¹ sugar in
completely dark period, Yield of microtuber plantlet¹ was higher (3.139 g) in 200 mg LCCC and 70 g L¹ sugar combination when treated with completely dark period. The highest
(11.31) number of tubers hill¹ was recorded from Granola plantlet, the maximum (247.00
g) fresh weight of tubers hill¹ was found in Diamant. The highest percentage (29.11) of
tubers A grade by number were recorded in Granola, the lowest (23.56) small tubers found
in Granola plantlet. The highest (10.970) yield of tubers was recorded under straw mulch.