IN VITRO CULTURE OF KINNOW EXPLANTS

Abstract

Kinnow mandarin is the most adaptable Citrus scion variety in Punjab, Pakistan. The explant tissues responded to culture media. BA and 2-4, D were essential for good callusing. The reproductive tissues such as nucellus have tendency of embryogenesis, while vegetative tissues like seedling leaves regenerated as shoot organogenesis. The seeds formed callus in MS medium supplemented with BA+2, 4-D each @ 1mg/litre and callus regeneration was observed in MS +GA+BA each @ 1mg/litre +2, 4-D (0.25mg/litre). Seedling leaves formed callus in MS supplemented with BA+GA each @ 1mg/litre +2, 4-D (0.5mg/litre) + proline (5mg/litre) and callus regenerated in BA + GA each @ 1mg/litre +NAA (0.5mg/litre) + Proline (5mg/litre). Nucellus regenerated in BA (1mg/litre) + 2, 4-D (0.5mg/litre) + Glutamine (5mg/litre). Buds were initially cultured in BA (1mg/litre) + GA (1mg/litre) +Glutamine (5mg/litre) and buds developed shoots in BA (2mg/litre) +NAA (0.5mg/litre) +GA (1mg/litre). Nucellus at 100 DAP (Days after Pollination) responded best (68%) at 60 Gray gamma radiation exposure. LD50 dose for mature seeds was slightly less than 100 Gray. Apical meristem explants were sensitive to gamma (γ) radiation doses. The maximum survival of explants (77%) was in control (No γ-radiation exposure) followed by 15 Gray (66% survival). The regenerated shoots were grafted on rough lemon seedlings.