ISHS Acta Horticulturae 631: XXVI International Horticultural Congress: Issues and Advances in Transplant Production and Stand Establishment Research
ENDOPHYTE ENHANCEMENT OF TRANSPLANT PERFORMANCE IN TOMATO, CUCUMBER AND SWEET PEPPER |
| Authors: | J. Nowak, J. Nowak, V.K. Sharma, E. A'Hearn |
| Keywords: | plantlet and seedling bacterization, in vitro co-culture, Burkholderia sp. strain PsJN, inoculum delivery |
| Abstract:
A plant growth promoting bacterium, Burkholderia sp. strain PsJN, isolated from surface sterilized onion roots, which forms both endophytic and epiphytic populations and stimulates growth and biotic and abiotic stress adaptation of plants, has been very effective in a clonal propagation (micropropagation) of potato (reviewed in the In Vitro Cell. Dev. Biol.-Plant, 34:122-130). Here we report results of the evaluation of the bacterial inoculum delivery methods to the seed propagated vegetables, cucumber, sweet pepper and tomato. The inoculation was done by seed soaking (bacterized seeds), root dip of 2-3 week-old seedlings (bacterized seedlings), or both (seed soaking and seedling dip) in the bacterial suspension in phosphate buffered saline (approximately 2x108 CFU/ml). To enhance the uptake of the bacterium and its colonization of plant interior, seedling inoculation was conducted after trimming root tips. Similar to potato, in vitro cultured vegetables responded well to the bacterization. The degree of the growth stimulation varied, however, with species and method of inoculation. Seedling bacterization was the most effective in tomato and sweet pepper. Double bacterization, i.e. bacterization of both seeds and seedlings, was the best for cucumber. Seed bacterization was ineffective with sweet pepper and somewhat effective with tomato and cucumber. The bacteria also affected early growth of cucumbers inoculated as greenhouse transplants, in pots, by pouring the bacterium suspension into the root system twice, before and after transplanting. The degree of the response also differed among cultivars of tomato and sweet pepper. Tomato hybrids responded better than a non-hybrid cultivar Scotia. Late season tomato hybrid, ‘Mountain Delight’, benefited less than a mid season hybrid, ‘Celebrity’, and an early hybrid, ‘Blazer’. Similarly, the earlier cv. of sweet pepper, ‘New Ace’, responded better than the later maturing, open pollinated, ‘Staddons Select’. In the greenhouse and field experiments conducted with seedling-inoculated transplants, the early growth and developmental stimulation caused by the bacterium did not always translate into significant effects on yield. | |
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