Asexual Propagation Of Juniperus Procera Hochst. Ex Endl. Through Rooting Of Branch Cuttings

The rooting responses of branch cuttings of Juniperus procera Hochst. ex Endl., obtained fromrnjuvenile and mature source plants to foul' plant growth regulators (PGRs), namely, indole-3-aceticrnacid (IAA), indole-3-butydc acid (lBA), naphthaleneacetic acid (NAA), and 2,4-rndichlorophenoxyacetic acid (2,4-D) at vadous concentrations (lrrJ to lrr9 iW) were examined ill sandrnculture. Assessments 011 survival, callusing and rooting of the cuttings were conducted 16 and 32rnweeks after the treatments. Odgin of root primordia was examilled microscopically, amIrnestablishment and perfonnance of stecklil;gs were done 011 sample rooted cuttings. It was found thatrnthe developmental stage of the source plants from which the cuttings were derived, and the type, asrnwell as the cOllcentratioll of the PGR, markedly affected the survival of the cuttings. About 77% ofrnthe cuttings obtained from Class 111 source plants (mature) died out withill the first 30 days afterrntreatment; while 34% of the cuttings obtained from Class 11 (mature), and 90% of the cuttingsrnobtained from Class I source plants (juvenile) survived until the end of the investigatioll. Callusingrnand rootillg of the cuttings were greatly affected by the developmental stages of the source plants.rnSixteen weeks after treahnent, meall percentage callusillg of cuttillgs obtained from Class I sourcernplants was significantly greater thall that obtailled from Class 11 source plants (p ,:; 0.05). Thernhighest attainable percelltage of callused cuttings obtained from Class I source plants was 56, treatedrnat 10-' 1'vlIAA and lrrs lW NAA. The corresponding percentage for the cuttillgs obtained from ClassrnII source plants was 29, treated at 10-' M IBA. At this time, ollly 2% of the cuttings obtained fromrnClass 1 source plants were rooted. Thirty two weeks after treatment, 24% of the cuttings obtainedrnfrom Class 1 source plants were rooted. By this time, only a single cutting from Class II sourcernplants rooted. The highest attainable percentages of rooted cuttings obtailled from Class I sourcernplallts was 60 treated at 1 rr7 1'1'1 IAA. The cOlrespondillg percentages were 50, 44 and 25 for NAArn(treated at 1rrJ J'rI), IBA (h'eated at lrrs 1'vI) alld 2,4-D (treated at 10-' and lrr7 M), respectively. Therncontrol resulted in 29% rooting. The melli/maximum attainable root numbers pel' rooted cuttings inrnIAA (treated at 10-' iW), IBA (h'eated at 1rr3 M), 2,4-D (treated at lrr9 M) and NAA (treated at lrrsrni',I) were 17.0 ± 4.1, 14.5 ± 12.5, 9.7 ± 6.7 and 7.0 ± 3.0, respectively. The mean root numberrnper rooted cuttings ill the conh'ol was 17.0 ± 1.7. The highest attainable mellll root length was 372rn± 51.5 mm, for cuttillgs treated at lrrJ M NAA. The correspollding values for IBA (h'eated at lrr3rnM), IAA (treated at 10-' M) and 2,4-D (treated at 10-' M) were 113.7 ± 11.7mm, 90.7 ± 5.6 mmrnand 67.7 ± B.B 111m, respectively. The /IIean root length of the cuttillgs rooted ill the cOllh'ol wasrn93.9 ± 7.3 /11m. Regression analysis showed that the cOllflibution of callusing to rootillg is velYrnsmall (Rt = 0.2070, P ,:; 0.05). III this species, cells of callus tissue, xylem rays, trach~ids, c011exrnalld cambium resulted ill the fonnatioll root primordia. Stecklings with well developed root systemsrnwere easily established and grew well, indicatillg the possibility of propagating the species by asexualrnmeans.

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