Limited tests indicate possibilities of rooting commercial varieties

G. F. RYAN E. F. FROLICH plied by momentary basal dip. The three ROOTING OF BARTLETT PEAR CUTTINGS rooting environments consisted of (1) a Summary of rooting under mist after treatment standard sash-covered propagating case with indolebuiyric acid-4.8 or 2 per cent Bartlett cuttings rooted best in recent tests shaded with cheesecloth when necessary, powder or 8 mg per ml quick-dip solution to obtain own-rooted trees of commercial (2) a polyethylene case cooled by an Per cent rooted pear varieties, and the new USDA varie- Source intermittent water spray, and (3) mist Sub-tip ties-Magness, Moonglow and Dawn- Date of Tip 6k-l Short applications at three-minute intervals. cuttings’ cuttings shoots were intermediate. Anjou rated last, with Vermiculite (industrial No. 1grade) was results not very successful rega.rdless of March 27 ...... I 100 100 .. used as the rooting medium, and it was April 19 .II 60 96 rooting medium or environment...... maintained at a minimum temperature of May8 ...... I 67 75 .. about 72’F by means of an electric heat- May 23 ...... II .. .. 77 June 15 ...... t 57 100 .. he rapid spread of pear,decline and ing cable. Bartlett grafted on P. Calleryana, grown in glass- the evidence that it may be asso- Bartlett cuttings hause; I grafted February 15; II grafted March 16. ciatedT with a rootstock-scion relationship The Bartlett cuttings began to show stimulated these studies to determine roots in less than a month, and all of whether Bartlett and Anjou varieties cent or 2 per cent IBA powder averaged them had rooted by the end of seven could be propagated on their own roots 72 per cent rooting under mist. An equal weeks. A second lot of Bartlett cuttings by means of softwood or semi-hardwood number placed in the propagating case taken from the same plants six weeks leafy cuttings. Also included were three completely failed to root. With the same later (May 8), and treated with 0.8 per new pear VarietieeMagness, Moonglow, treatments, a third lot of Bartlett cuttings and Dawn-recently named and regis- under mist averaged 85 per cent-the tips tered by USDA. In addition to good fruit Bartlett pear cuttings showing root system at rooting 57 per cent, and the sub-tip and end of seven weeks. quality, Magness and Moonglow have a basal cuttings, 100 per cent. high degree of resistance to fire-blight. In March, 70 more Bartlett scions and Rooted cuttings of these varieties would 70 Anjou scions were grafted in the same be expected to produce trees with blight- way as the first set. Cuttings were taken resistant roots as well as,tops. from the Bartlett scions after five weeks. Scions of Bartlett and the three USDA Sub-tip and basal cuttings which received varieties were grafted in February, 1961, the two stronger treatments (0.8 per cent onto evergreen pear, Pyrus Calleryana, in and 2 per cent IBA) rooted 93 to 100 per one-gallon cans on a glasshouse bench. cent under mist, and tip cuttings with the Cuttings were available six weeks after same treatments rooted 60 per cent. In grafting. Shoots 5 to 8 inches long, still the other two environments with these soft at the tip, were cut into two or three cuttings each. They were divided into EFFECT OF THREE ENVIRONMENTS ON ROOT- groups, given two different growth sub- ING OF BARTLETT CUTTINGS stance treatments, and placed under three Per cent rooted ~~ rooting environments. The treatments Mist Polyethylene-- Case were made using 0.8 per cent IBA (in- IBA IBA IBA IBA IBA IBA dolebutyric acid) powder “Hormodin 3” 0.8% 2% 0.8% 2% 0.8% 2% and IBA at 8 milligrams per milliliter Tip ...... 60 60 60 20 40 40 (mg per ml) in 50 per cent alcohol, ap- Sub-tip 6 base. 93 100 50 36 21 43

10 CALIFORNIA AGRICULTURE, APRIL, 1962 treatments, maximum rooting was 6 per was again in the propagating case, where cent. With 0.3 per cent IBA and no treat- 33 per cent of the tip and 44 per cent of ment, rooting was not over 6 per cent, the sub-tip and basal cuttings rooted. regardless of location. Under mist the results were 17 per cent The next lot of cuttings from the second and 31 per cent respectively. Rooting was set of Bartlett scions consisted mostly of negligible under polyethylene. Treat- shoots not over 4 inches long. These were ments in this experiment were with 0.8 treated with 0.8 per cent IBA or with a per cent and 2 per cent IBA. 2 per cent NAA (naphthaleneacetic acid) About five weeks after the first lots of powder, and inserted in vermiculite in Anjou cuttings were taken, a second lot 21/-inch peat pots. The IBA-treated cut- was available from each group of plants. tings rooted 77 per cent under mist and This time rooting percentages were even 47 per cent in the closed case. For the lower than for the first two lots averaging NAA-treated cuttings the results were 35 only 3 to 5 per cent. per cent under mist and 58 per cent in the The rooting response of Magness, closed case. Dawn, and Moonglow was intermediate between Bartlett and Anjou. Cuttings of Magness taken in March and June aver- aged 33 per cent for tip and 64 per cent for sub-tip and basal cuttings. A small number of cuttings taken May 8 did not root as well. George F. Ryan, formerly Assistant Professor of Horticultural Science and Assistant Horticulturist, Experiment Sta- tion, Los Angeles, is now Assistant Horti- culturist at the Citrus Experiment Station, Lake Alfred, Florida. Edward F. Frolich is Laboratory Technician IVY Depart- ment of Plant Biochemistry, University of California, Los Angeles. This report is based on Project 1068.

ROOT DEVELOPMENT OF SAFFLOWER SAFFLOWER,a crop of increasing impor- tance in California, develops the deepest root system of any annual crop yet inves- tigated by the Department of Irrigation. Under favorable soil conditions, mature Bartlett pear cutting showing root development Rooted cuttings of Bartlett (left) and Magness plants can completely exhaust the avail- through a peat pot. (right) 4% months after cuttings were made. able soil moisture to a depth of 10 feet and can utilize most of the available mois- Survival after rooting these shoots were made into two or three ture to a depth of 12 feet (the greatest Survival and growth after rooting has cuttings each, treated, and placed in the depth sampled). There is little difference been one of the problems with producing three rooting environments. Response of in root development in present commer- own-rooted pear trees. In these experi- the Anjou cuttings was much different cial varieties. ments, the rooted cuttings were potted than Bartlett. Total rooting in the propa- Because of this characteristic, there is and transferred to a closed case where gating case was less than 15 per cent and little or no yield response to irrigation they were left until growth started or, results showed no apparent relationship during the growing season when safflower when rooted in peat pots, were moved to type of cutting or to treatment-which is planted on deep soils of high water- into gallon cans in a high-humidity glass- included concentrations up to 20 mg per holding capacity-provided that the soil house. In the first two lots 90 to 95 per ml IBA and .02 per cent 2,4,5-TP (2,4,5- is moist to great depths at planting time cent of the rooted cuttings survived and trichlorophenoxyacetic acid) -as well as and that there are no tight soil layers to most of these grew vigorously. Cuttings lower concentrations and no treatment. retard root development. Minimizing taken March 27 made as much as 3 to 4 Other rootings were even less satisfactory, surface irrigation during the growing feet of growth by mid-August. Growth totalling 1 per cent under mist and 5 per season is important because safflower is was best on cuttings that rooted rapidly. cent under polyethylene. highly susceptible to root-rot injury in The Anjou scions grafted in mid- Similar cuttings taken two weeks later wet soils.-D. W. Henderson, Associute March produced shoots up to 10 inches from another group of Anjou grafts gave Professor of Irrigation, Dept. of Irriga- long in less than a month. A hundred of somewhat better results. The best rooting tion, University of California, Davis.

CALIFORNIA AGRICULTURE, APRIL, 1962 11