Prakash Babu Adhikari

Yield and fruit quality of tomato ( Lycopersicon esculentum Mill.) cultivars established at different planting bed size and growing substrates

This study was carried out to investigate the yield and fruit quality of tomato (Lycopersicon esculentum Mill.) cultivars using different plant bed width and growing substrates in Hwacheon Farm, 2011. Transplants of tomato cultivars ‘Campari’, ‘Temptation’, ‘Annamay’, and ‘Adoration’ were planted at 20 cm, 40 cm, 60 cm, and 80 cm bed width and same cultivars were grown at cocopeat, rockwool and masato in early July, 2011 in a greenhouse. Planting bed size significantly affected the fruit number, marketable fruit number (%) and weight (g), and total yield (g) per plant. Plants grown at 60 cm bed width yielded the highest fruit number (22.4), marketable fruit number (56.0%), marketable fruit weight (356.8 g) and total yield (564.5 g) per plant. Bed width had no significant effect on fruit size and quality characters. Plants grown in cocopeat produced the highest marketable fruit number (56.2%) per plant and yielded the greatest (445.6 g) marketable yield per plant. Plants grown in cocopeat substrate produced higher fruit number (5.2%) and total yield (0.7%) than that of rockwool substrate. Fruit size and fruit quality characters showed no significant differences within growing substrates. Hence, planting the tomato cultivars in single row at 60 cm bed width is better approach to optimize the production space in greenhouse and cocopeat is recommended as potential growing substrates for tomato cultivation to increase its yield and fruit quality characters.

High frequency somatic embryogenesis and plant regeneration of interspecific ginseng hybrid between Panax ginseng and Panax quinquefolius

Background Interspecific ginseng hybrid, Panax ginseng × Panax quenquifolius (Pgq) has vigorous growth and produces larger roots than its parents. However, F1 progenies are complete male sterile. Plant tissue culture technology can circumvent the issue and propagate the hybrid. Methods Murashige and Skoog (MS) medium with different concentrations (0, 2, 4, and 6 mg/L) of 2,4-dichlorophenoxyacetic acid (2,4-D) was used for callus induction and somatic embryogenesis (SE). The embryos, after culturing on GA3 supplemented medium, were transferred to hormone free ½ Schenk and Hildebrandt (SH) medium. The developed taproots with dormant buds were treated with GA3 to break the bud dormancy, and transferred to soil. Hybrid Pgq plants were verified by random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) analyses and by LC-IT-TOF-MS. Results We conducted a comparative study of somatic embryogenesis (SE) in Pgq and its parents, and attempted to establish the soil transfer of in vitro propagated Pgq tap roots. The Pgq explants showed higher rate of embryogenesis (~56% at 2 mg/L 2,4-D concentration) as well as higher number of embryos per explants (~7 at the same 2,4-D concentration) compared to its either parents. The germinated embryos, after culturing on GA3 supplemented medium, were transferred to hormone free ½ SH medium to support the continued growth and kept until nutrient depletion induced senescence (NuDIS) of leaf defoliation occurred (4 months). By that time, thickened tap roots with well-developed lateral roots and dormant buds were obtained. All Pgq tap roots pretreated with 20 mg/L GA3 for at least a week produced new shoots after soil transfer. We selected the discriminatory RAPD and ISSR markers to find the interspecific ginseng hybrid among its parents. The F1 hybrid (Pgq) contained species specific 2 ginsenosides (ginsenoside Rf in P. ginseng and pseudoginsenosides F11 in P. quinquefolius), and higher amount of other ginsenosides than its parents. Conclusion Micropropagation of interspecific hybrid ginseng can give an opportunity for continuous production of plants.