through zygotic embryos

2. OBJECTIVE
Aims to induce high volume indirect somatic
embryogenesis in the papaya cultivar Co7.
In all the cases pH of the medium was maintained at 5.8.

3. METHODOLOGY
• Fruits (80, 100,120, 140 & 150 day-old) of Co7 were collected from
Horticultural College and Research Institute, TNAU
• Aseptically excision of zygotic embryos (ZE) were done under
a stereomicroscope
• Isolated ZE transferred to callus induction medium [CIM] {half-strength MS basal salts
and vitamins, 400 mg/L of glutamine, 6% sucrose, 4 g/L phytagel supplemented with either 0.1-12.0 mg/L 2,4-D or 2,
5, 10, and 15 µM TDZ}

4. • Pro embryogenic calli were transferred onto an embryo induction medium {half-strength MS salts, 50 mg/L
myo-inositol, full strength MS vitamins, 400 mg/L glutamine, 3% sucrose, 100 mg/L activated charcoal and 0.4% phytagel
supplemented with 0.1-10.0 mg/L 2,4-D}
• SE transferred to the maturation medium
• The maturation medium {static OR liquid suspension cultures, half strength MS basal medium supplemented with varying
concentration of ABA and sucrose (1%)}.
• Torpedo shaped embryos were turned to cotyledonary stage indicating the physiological maturity.
• These are transferred onto a modified MSR [MS salts, MS vitamins, 3% sucrose, 100 mg/L casein hydrolysate, 100
mg/L malt extract, 4 g/L phytagel] medium supplemented with 0.02 mg/L NAA and BAP (0.1-1.0 mg/L) or kinetin (1.0-
3.0 mg/L) for shoot induction.
• Shoots of 2-3 cm height with 2-3 trilobed leaves were transferred onto an MSL {MS salts, vitamins, 3%
sucrose] medium supplemented with varying levels of IBA (0.25, 0.50, 0.75, 1.0, and 2.0 mg/L)} for root induction.
• the plantlets were further cultured on hormone-free MS solid medium
• Plantlets with well-developed roots were transferred to plastic pots containing sand, soil
and farmyard manure (1:1:1 ratio) enriched with AM and were kept in the greenhouse for hardening

5. RESULTS
 Preparation of Explants: Fruits of 80, 100, 140 and 150 days old not form embryogenic
calli. The ZE derived from white seeds of 110–120-day-old fruits resulted in better
embryogenic callus.
 Induction of embryogenic calli: The percentage of explants (87%) producing calli was
observed with 2.0 mg/L of 2,4-D whereas the highest callus formation (93%) from the ZE
was recorded on CIM supplemented with 5 µM of TDZ, but limited embryogenesis (12%) .
The mean number of somatic embryos produced from every ZE was as high as 65.2%
 Maturation of Somatic Embryos: ABA (40 µM) produced significantly highest number of
cotyledonary somatic embryos. Liquid medium induced the development of higher number
of cotyledonary embryos.

6.  Plant Regeneration from SE: MSR medium containingNAA (0.02 mg/L) and BAP (0.4 mg/L) whereas
kinetin adversely affected the regeneration. The shoot regeneration was as high as 62.32%
 Rooting and Hardening of Plantlets: A rooting efficiency of 60.07% rooting was achieved on MS medium
added with 1.0 mg/L IBA