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Abstract
The root-knot nematode M. javanica did not develop on two-month-old peach seedlings of the resistant cvs. Nemaguard and Okinawa, even when they were copiously inoculated with egg masses of the nematode, under conditions in which seedlings of the susceptible ‘Baladi’ supported a considerable nematode population. However, when “resistant” seedlings were wick-fed with kinetin or NAA, the development of a normal nematode population became possible. The 2 substances produced synergistic stimulating effects on nematode development; they also increased the nematode population in the susceptible cultivar.
The effect on the plant of NAA supplied by this technique was expressed in increased root growth and reduced top growth. It caused the development of swelled, non-suberized branch roots which became the favored habitat of the nematodes. Kinetin at the concentrations used, on the other hand, had no visible effect on the growth of the seedlings. The possible role of kinetin and NAA in altering the host-parasite relationship is discussed.
Abstract
Cytokinin and auxin levels were examined in the roots of peach cultivars, resistant (‘Nemaguard’ and ‘Okinawa’) and susceptible (‘Baladi’ and ‘L 198-12’) to the root knot nematode Meloidogyne javanica. This approach was taken in the light of our earlier finding that this nematode developed and completed its life cycle in seedlings of a resistant cultivar when they were wick-fed with kinetin and 1-naphthylacetic acid (NAA). The cytokinin activity in roots of resistant rootstocks was significantly lower when compared with susceptible rootstocks. Wick-feeding with kinetin and NAA increased cytokinin-like activity in the roots of a resistant rootstock. Significant differences were found in the activity of several basic-ether soluble auxin-like growth promoters.
Abstract
The effect of 7 growth inhibitors on the development of the nematode Meloidogyne javanica (Treub) Chitwood in the roots of the susceptible peach rootstock ‘Baladi’ was examined. Thiourea, maleic hydrazide, triiodobenzoic acid and Actidione most effectively inhibited gall formation, as well as maturation of nematodes in galls. 7-aza-indole, 2-hydroxy-5-nitrobenzyl bromide and 2,6 diaminopurine were effective in preventing gall formation, but once galls had formed, nematode development was affected less.
Abstract
The rest period of peach buds was broken by application of several compounds. DNOC-mineral oil, thiourea, aqueous DNOC, KNO3, gibberellic acid and kinetin were found to be active. Combinations of active compounds found to be most efficient were: DNOC-mineral oil + thiourea; DNOC-mineral oil + gibberellic acid; and KNO3 + thiourea. Potassium nitrate and kinetin mainly advanced flower bud opening, while thiourea had a more pronounced effect on leaf bud opening. Combinations of pairs of the 3 compounds, DNOC-mineral oil, thiourea and KNO3 were best for commercial use.