Budding methods

1. Budding methods • T-budding or shield budding • Patch budding • Chip budding

2. Features of T-budding • widely used for fruit and ornamental trees, as well as roses • two methods: “wood in” and “wood out” (i.e., whether the bark of the scion is slipping or not) • bark of the stock must be slipping

8. How healing occurs with T-budding • when bark of the stock is lifted, separation occurs in young xylem • primary union is between the phloem on the inner shield face and young xylem on the stock’s surface • callus originates almost entirely from rootstock tissue • for successful “takes”, a continuous cambium must be established between bud and rootstock

11. Timing the T-budding operation • Fall budding (July to early Sept): budwood needn’t be collected and stored, but budding must be done while the stock is actively growing • Spring budding (Mar and Apr): budding must be done before bark stops slipping on the stock, usu. by late spring; budwood must be collected and stored prior to budding • June budding (late May to early June): it is used to obtain a 1-yr-old budded tree in 1 season

13. Chip budding • a chip (with a bud) is placed into a stock that has had a chip removed • neither stock nor scion needs to have slipping bark • cambia of scion chip and stock must be matched closely

15. Patch budding • scion patch (w/bud, w/o wood) is slid off sideways, placed into a stock after the bark “patch” is removed • works well on thick-barked species (e.g., pecans, walnuts) • requires bark of both scion and stock to be slipping easily • usu. done in late summer or early fall

17. Factors influencing success in grafting/budding • the kind of plant • the healing environment (temperature, moisture, oxygen) • growth activity of stock and/or scion • grafting technique • viruses, insects, disease • polarity • limits (closeness of the botanical relationship) • graft incompatibility

18. Symptoms of graft incompatibility • yellowing foliage (esp. in the latter part of the growing season) • premature death of the tree • difference in growth rate or vigor of the scion, compared with the stock • graft components break apart cleanly at the graft union

19. Types of graft incompatibility • anatomical flaws (e.g., vascular discontinuity) • localized incompatibility (i.e., requires contact between stock and scion) • translocated incompatibility (i.e., not overcome by an interstock) • pathogen-induced incompatibility (i.e., a latent virus introduced by grafting from a resistant to a susceptible partner)

20. Translocated incompatibility • ‘Nonpareil’ almond/’Marianna 2624’ plum - incompatible • ‘Texas’ almond/’Marianna 2624’ plum - compatible • ‘Nonpareil’/’Texas’/’2624’ - incompatible (phloem breakdown at the Texas/2624 junction means that the “incompatibility factor” is translocated)