Sapling Production in Citrus

• Importance: Citrus propagation is difficult due to nucellar polyembryony and slow multiplication by conventional methods. Tissue culture ensures rapid availability of disease-free rootstocks and scions.
• Challenges: Citrus plantlets are highly sensitive to transplant shock and require longer hardening compared to banana.

Stages

a. Primary Hardening:

• Plantlets transferred from culture bottles to small cups with sterilized cocopeat and sand.
• Maintained in mist chamber at 85–90 percent RH and 26–28°C.
• Shaded environment prevents desiccation.
• Period: 8–10 weeks.

b. Secondary Hardening:

• Transplanted into polybags (10 × 15 cm) filled with soil: sand: FYM (2:1:1).
• Kept under 50 percent shade net for 2–3 months.
• Regular nutrient sprays of NPK (19:19:19 at 0.2 percent) and biocontrol agents.
• Plants attain 25–30 cm height with 8–10 leaves.

c. Field Readiness:

• Tissue-cultured citrus saplings usually require 3–4 months of hardening.
• Recommended for establishing disease-free nucleus and breeder stock in citrus orchards.