Propagation of citrus rootstocks in greenhouses by seed, stem cuttings and tissue culture to accelerate budded tree production for out planting.

Transcription

1 Propgtion of citrus rootstocks in greenhouses by seed, stem cuttings nd tissue culture to ccelerte budded tree production for out plnting. Richrd C. Beeson Jr. Assoc. Professor Mid-Florid Reserch nd Eduction Center - Apopk University of Florid

2 Bckground Seed sources of trditionl rootstocks re shrinking. Seed of new vrieties of rootstocks very low or non existent. Options re stem cutting of tissue culture

3 Rooting cutting I hve history of propgting woody plnt cutting beginning Strting with zle nd rhododendron cuttings F Lter Live ok, Americn Elm nd numerous other species First cuttings of trifolites in 2013

4 First propgtion of citrus cuttings reported in lte 1800 s First use of uxins ws in Bck then, citrus stems were rooted in glss enclosed rooting boxes in Stuck in snd nd hnd wtered frequently. IAA t 2000 to 3000 ppm ws the stndrd In the mid-1950 intermittent mist cme into fvor using 120VAC vlves NAA ws lso used, but t ½ the concentrtion

5 Stem mturity For growing shoots, higher success nd greter root growth occurred with cutting tken from below the first 12 inches Auxin Use of thickening gent (Cell-u-wett) incresed rooting success to over 90% compred to using wter s the solvent

6 In 2014 strted experimenting with rooting of stem cuttings Tble 1. Description of types of cuttings Clss Description 1 1 node, with 1 lef cut between nodes t the bottom of stem 2. 2 nodes, with 2 leves, cut between nodes t the bottom 3 3 nodes, with 3 leves, cut between nodes t the bottom 4 2 nodes, with 2 leves, cut just below the bottom node 5 3 nodes, with 3 leves, cut just below the bottom node 6 4 nodes, with 4 leves, cut just below the bottom node

7 Stem cuttings Shoot mturity Mture hrdwood cuttings were superior to softwood cuttings. For ornge rootstocks, single node (l lef nd 1 bud) generlly rooted within 6 weeks under overhed mist from mid-mrch to mid-november. Except sour ornge, 20 other trifolite generlly rooted >90 during this period. From lte November to lte Februry, rooting ws less thn 20% with poor root growth. However heting the substrte to 80F incresed rooting,but only to < 40%

8 Tretment Auxin conc. Root dry mss (g) New shoot length (mm) Number of shoots 1 node cut t stem gh 23.8 lm 0.21 h 1 node cut t stem fgh 70.8 efgh 0.89 def 1 node cut t stem fgh 12.6 m 0.21 h 1 node cut t stem gh 30.2 klm 0.53 g 2 node cut t stem gh 38.9 jklm 0.58 g 2 node cut t stem d 61.6 fghij 0.79 efg 2 node cut t stem de 86.3 cdef 0.95 def 2 node cut t stem de 80.9 cdefg 1.03 cde 3 node cut t stem cd bc node cut t stem b 68.6 efgh 1.16 bcd 3 node cut t stem b b 1.5 The more nodes (leves) the greter the shoot growth. However, more nodes, more sprouts I use single lef/single node cutting for trifolites

9 Tble 1: Rooting percentge, root nd shoot dry msses of single node cuttings treted with 4000 or 7500 ppm uxin (Dip&Gro) concentrtions Dte 4000 ppm uxin 7500 ppm uxin Percent Percentge rooted rooted Root Dry mss (mg) Shoot elongtion (mm) Root Dry mss (mg) Shoot elongtion (mm) 6 My My b August b September b b September 14 October November December Jnury b Jnury Februry Februry Mrch April April b 9.8 b My June b

10 Effect of bottom het on root dry mss during the winter for Huhrski Kuhrski 90.0 Root dw (mg) b b b b b b b b 1/12-2/23 2/5-3/17 2/ /18-4/ Amb Temp 4000 Bottom Het 7500 Amb Temp 7500 Bottom Het

11 Tissue culture hrdening Tissue cultured plnt were obtined 5 times over the course of yer. Initited 6 July, 28 September, December 14, Mrch 9, My 17 Rootstocks were : C35 C-54 Sour Ornge US0812 Swingle -13 Kuhrsek-13

12 Tissue Culture Plntlets were removed from tissue culture boxes Roots were cut off nd stems cut into 2 cuttings No dditionl uxin ws pplied Plntlets were stuck in 60% pet:40% perlite nd plced in tents hevily shded Reltive humidity ws grdully reduced from >90% to 50%, then shding ws Removed one t time. Tretments consisted of lowering conditions every 2, 3, 4 nd 5 dys

13 Conclusions 2 dys lwys nd 3 dy for some rootstock produced the best rooted cuttings Cutting hrdened from Mrch to September were most successful > 90% Cutting initited in mid-novenber through the end of Mrch were mostly filure Use of bottom het from mid-october through Mrch ws successful with 80 degree tempertures