Development, maturation, and postharvest responses of Actinidia arguta (Sieb. et Zucc.) Planch, ex Miq. fruit

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1 New Zeala Journal of Crop a Hortcultural Scence ISSN: (Prnt) (Onlne) Journal homepage: Development, maturaton, a postharvest responses of Actnda arguta (Seb. et Zucc.) Planch, ex Mq. frut A. K. Hassall, G. J. Prngle & E. A. Macrae To cte ths artcle: A. K. Hassall, G. J. Prngle & E. A. Macrae (998) Development, maturaton, a postharvest responses of Actnda arguta (Seb. et Zucc.) Planch, ex Mq. frut, New Zeala Journal of Crop a Hortcultural Scence, 26:2, 95-08, DOI: 0.080/ To lnk to ths artcle: Publshed onlne: 22 Mar 200. Submt your artcle to ths journal Artcle vews: 369 Vew related artcles Ctng artcles: 2 Vew ctng artcles Full Terms & Cotons of access a use can be fou at

2 New Zeala Journal of Crop a Hortcultural Scence, 998, Vol. 26: /98/ $7.00 The Royal Socety of New Zeala Development, maturaton, a postharvest responses of Actnda arguta (Seb. et Zucc.) Planch, ex Mq. frut A. K. HASSALL G. J. PRINGLE E. A. MACRAE* The Hortculture a Food Research Insttute of New Zeala Ltd Mt Albert Research Centre Prvate Bag Auckla, New Zeala emal: emacrae@hort.cr.nz Abstract Frut from a range of seedlng selectons of Actnda arguta, or hybrds between A. arguta a A. melanara were compared for frut growth, maturaton, a postharvest storage. Tmng a duraton of the flowerng perod vared. Long frut had greater maxmum growth rates than rou frut, but the tmng of maxmum growth (25-30 days after anthess (DAA)) teed to be smlar for all selectons a was smlar to that for other Actnda speces. A smaller seco peak n growth rate occurred arou DAA. Frut on the vne progressed from a slow to a rapd ncrease n soluble solds concentraton, typcal of commercal kwfrut. Ths occurred at the tme when temperatures n New Zeala are at ther hghest (February), catng a prmarly physologcal cause for an ncrease n soluble solds concentraton rather than a response to lowered temperatures as generally postulated for commercal kwfrut (A. delcosa). Maxmal dry matter accumulaton also vared accordng to selecton, wth some selectons able to contnue to accumulate carbohydrate durng on-vne rpenng. There was varaton between selectons n rate of on-vne softenng, wth the most rapd beng 4 days. Frut wth A. melanara n ther parentage sometmes developed reddenng of the skn or flesh or both as they Author to whom correspoence s to be addressed. H9706 Receved 8 December 997; accepted 6 Aprl 998 matured a rpened. Frut softenng a reddenng began at ether the stem e or the stylar e depeng on selecton. Soft frut stored 2 weeks at 0 C, whereas frm frut lasted at least 6 weeks. There was no dfference n storage longevty between 0 a 3 C. Compressve a puncture tests showed smlar patterns of softenng, however compressve tests were non-destructve, more senstve, a hence more useful. No major dsorders or dseases were noted, a shrvel (water loss) was the most sgnfcant cause of potental commercal loss. In red cultvars, the ablty to colour after harvest was severely retarded f frut were held at low temperatures. These results cate there wll be some dffculty n selectng a sutable maturty parameter that wll allow a commercal postharvest lfe for A. arguta types. Keywords Actnda arguta; frut growth; frut maturaton; frut storage; frut frmness; frut carbohydrate; frut colour INTRODUCTION Actnda arguta (Seb. et Zucc.) Planch, ex Mq. belongs wthn a secton of the genus Actnda whch s dfferent to that of commercal kwfrut, A. delcosa var. delcosa (A.Chev.) C.F. Lang et A.R. Ferguson 'Hayward' (Ferguson 990). A. arguta has dplod, tetraplod, hexaplod, a octoplod cytotypes, a characterstcally has small smooth -sknned frut that grow sngly or n multples. The frut have been reported to contan a hgh vtamn C content, good flavour, a to be more cold resstant durng growth than commercal kwfrut. Therefore, the speces s of commercal nterest n several countres (e.g., Kabaluk et al. 997) as a potental new frut varety. One factor lmtng ts advance s knowledge of the preharvest a postharvest behavour of the frut. Prelmnary results (R. L. Cotter & E. A. MacRae unpubl. data) cated that: () A. arguta had a much shorter growth a maturaton perod (3 months compared

3 96 New Zeala Journal of Crop a Hortcultural Scence, 998, Vol. 26 to 5-6 months for A. delcosa); (2) a starch/sugar converson smlar to that of A. delcosa occurred at frut maturty; a (3) frut were able to store at 20 C week only after harvest. Current commercal practse s to harvest frut as a strp pck when c. 0% of the frut on a vne are soft to the touch. Wth consderable effort beng nvested nto breedng A. arguta, ether for tself or as a parent n a cross (Ferguson 990; Whte & Beatson 993), t s tmely to compare a number of dfferent selectons to evaluate the range a lmts of frut developmental a postharvest behavours, as they currently exst. We report here on the comparson a evaluaton of frut growth, maturaton, a rpenng/storage behavour of a number of A. arguta selectons a hybrds. The selectons were chosen to represent the range of frut types (based on breeders' evaluatons) currently avalable, a selectons were evaluated for storage only f there were suffcent frut on a vne to allow the numbers requred for assessments of storage a shelf lfe. MATERIALS AND METHODS Plant materal Twenty vnes, each an vdual seedlng of Actnda arguta (2n=4x=l 6) or a hybrd between A. arguta a A. melanara Franch., were planted n 988 on T-bars at the HortResearch Orchard, Kumeu, New Zeala or at the HortResearch Orchard, Te Puke, New Zeala. Frut assessed fell nto several nterrelated groupngs. Herbarum specmens of some have been deposted wth CHR (Lacare Herbarum, Chrstchurch). AAll_0 (Collecton No. ARF 67,82), named 'Issa' has been confrmed as beng hexaplod (A. R. Ferguson pers. comm.). AA0_0 (Collecton No. ARF 70,8) a AA02_0 (CollectonNo. ARF 9,82); early seedlng selectons of Actnda arguta, were used as female parents n a number of ntra- a nter-specfc crosses between Actnda arguta a tself or Actnda melanara. Red colour appeared when A. melanara had been ntroduced to a cross. There was always a mxture of sngle a multple frut bunches wthn any one selecton although there was often a bas towards one or other. Parentage of each seedlng selecton s outlned (Table ) a specfc characterstcs of each selecton are brefly outlned n Table 2. The selectons studed were chosen to represent the range of shapes, szes, colours, or tmng n flowerng a rpenng, a had to have suffcent crop to allow frut numbers for ether developmental studes or postharvest storage assessments or both. Frut were assessed n 994/95 or 995/96 frutng seasons. Nne of the selectons were assessed for maturaton a storage over both seasons to evaluate seasonal varaton. Frut growth In early November, flowers were tagged at anthess (cupped petals), on consecutve days from the date of frst flower openng untl fnal flower openng. Numbers of flowers tagged each day was recorded. Frut growth was measured (length a large a small dameters) usng Mtutoyo Corporaton seres 500 dgtal callpers. In the 994/95 season, records were made of 0 frut (sngle or kng flowers from trplets) from each selecton whch had been tagged on the same day n the mddle of the flowerng perod. Measurements were repeated on four selectons durng the 995/96 season. Table Parentage of seedlngs evaluated. (AA = Actnda arguta; ME = Actnda melanara.) Female parent AA02_0 AA0_0 AA05_0 AA04_02 AAME0_0 Male parent AA3_0 AAME0_05 AA3_0 AA04_0 AA3_0 ME0_0 ME0_0 ME0JM AAME0_05 Progeny J5I3; J5H3; K2D4; K3E5; J32 K3G; K2E; M4F6; K3G2 K6G C3C3 K3I J4D4; J5F3 K6H5 E3H6 E4I6

4 Hassall et al. Evaluaton ofactnda arguta 97 To relate the growth measurements to frut weght, 20 frut were harvested from each selecton n the 995/96 season a frut weght a the dameters a length were measured. Ths was repeated four tmes at 3-weekly ntervals startng n md December a the data used to estmate frut volume durng growth (Snelgar et al. 992; Tombes et al. 994). The equaton (C. Clayton 996): weght = (length x dameter x dameter 2) /000 x slope of the regresson; was able to predct frut weght wth an error of <5% at all tme ponts a for both frut shapes. The regresson slope vared between a for the four selectons used to establsh the valdty of the equaton, a a mean value was used to calculate predcted weght for the selectons not modelled. Frut maturaton At regular ntervals untl frut were vne-rpe (between md January a md Aprl), 0 frut tagged on the same day per selecton, were harvested a assessed for a range of maturty characterstcs. The characterstcs measured were based on those used n other Actnda frut assessments. Frut were weghed a skn a flesh colour measured usng a Mnolta Chroma Meter wth a D65 lght source (II Reflectance; Mnolta Camera Co., Osaka, Japan). Colour was expressed as chroma (ntensty of colour) or hue angle (actual colour) accordng to McGure (992). The skn was wped clean wth a tssue a one skn colour readng taken from the equator of the frut. Flesh colour was then measured after removal of a mm slce of skn from the same poston. Frut frmness was measured usng a 3 mm dameter penetrometer probe (movng at 50 mm/mn) on the Unversal Materals Testng Machne (Instron, Canton, Mass., Unted States). Two measurements were taken at 80 to each other on the equator of the frut (skn removed as for flesh colour). Soluble solds concentraton (SSC) of a slce from the equator of the frut was measured usng an Atago N- refractometer. Dry matter concentraton (DM) was measured by dryng a 4 mm slce from each sde of the prevous equatoral slce to a constant weght n an oven at 65 C for c. 8 h. Frut were grouped n lots of three or four to form three replcates per assessment. Seed colour was measured by estmatng the percentage of dark seeds n each slce from the slces taken for DM measurement. In a further experment, two selectons (J5H3, J5I3) were dvded nto early, mddle, a late flowerng a assessed separately durng maturaton n the 995/96 season. Ten frut replcates were used. Table 2 Frut characterstcs of Actnda arguta a A. arguta x A. melanara seedlngs. Weght (g) Skn Colour Flesh Shape AA0 0 AA02 0 AA 0 J5I3 J5H3 K2D4 K.3E5 J3I2 K3G K2E M4F6 K3G2 K.6G C3C3 E3H6 E46 K.3I J4D4 J5F3 K6H red blush red blush red blush red blush red red red red, nner percarp red, nner percarp red, nner percarp red, nner percarp red red oval rou rou rou rou rou rou rou heart rou-oval rou rou-oval rou oval oval oval heart oval, wasted oval oval heavy crop heavy crop sngles-trplets sngles-trplets large flowers, sngles, few trplets sngles-trplets sngles, few trplets sngles-trplets sngles-trplets sngles-trplets sngles-trplets large bunches, sngles-trplets sngles-septuplets sngles, few trplets

5 98 New Zeala Journal of Crop a Hortcultural Scence, 998, Vol. 26 Frut storage When 5-0% frut on the vne were soft, frut were harvested for postharvest assessments. Frut (wth stalks on) were harvested from the vne wth scssors a transported to the laboratory n paper bags where they were sorted (<2 h after harvest) nto expermental treatments as follows. Experment To compare the behavour of frm frut durng storage at 0 or 3 C, frut from four selectons were harvested n the 994/95 season, segregated nto frm or soft frut a packed separately nto kwfrut trays wth a cotton wool lned kwfrut plx a polylner. Soft frut were retaned a stored at 0 C to allow comparson between storage responses of frm a soft frut at one temperature. At weekly ntervals frmness was measured noestructvely on the same 0 frut whle at storage temperature. Frut were compressed 0.2 mm on the Instron Unversal Materals Testng Machne at a speed of 50 mm/mn. After wannng (24 h at 20 C), frut weght, skn a flesh colour, frmness (destructve a non destructve), SSC, a the presence of rots, shrvellng a other dsorders were assessed at 0, 3, a 6 weeks for frm frut a at 0 a 2 weeks for soft frut. Experment 2 To compare the effects of the presence of a frut pedcel, contaners wth dfferent gas a water loss characterstcs, a relatve temperature on shrvel a rate of water loss from frut durng coolstorage, frut were harvested n the 994/95 season a treated as follows: () frut from one selecton were placed at 0 C n punnets a covered wth cellophane wth or wthout perforatons; (2) frut from two selectons were placed at 0 or 3 C n punnets wth cellophane a no perforatons; (3) frut, wth or wthout frut pedcel, from a fourth selecton was placed at 0 C; a (4) frut, wth or wthout frut pedcel, of a ffth selecton were stored at 3 C. All experments conssted of seven replcate 250 g punnets wthout perforatons, each contanng 0 frut. After 0, 3, a 6 weeks of storage, frut were warmed to 20 C a assessed for frut weght, skn a flesh colour, frmness, SSC, a the presence of rots, shrvellng a other dsorders. Experment 3 To nvestgate shelf lfe after storage, three selectons from the 995/96 season were harvested nto ldded punnets wth eght perforatons (20 frut per punnet) a stored at 0 C. Sx punnets per selecton were removed from coolstorage at 0,3,4, a 6 weeks of storage. After warmng, frut from three punnets were assessed for frut weght, frmness, SSC, colour, a dsorders. The remanng three punnets were weghed daly durng shelf lfe at 20 C a assessed for frut weght, frmness, SSC, colour, ethylene a CO 2 concentratons, rots, shrvellng a other dsorders. Two storage temperatures were chosen for comparson as t was unknown whether chllng njury, or low temperature breakdown (whch can occur n other speces of Actnda) mght occur. Selectons used n storage experments were chosen solely on the bass of frut avalablty a to vary the types (e.g., red or not red, parentage dfferences) examned. Parameters for assessment were selected based on prevous methods for other Actnda speces. Compressve (non-destructve) frmness measurements were ncluded when t became apparent that destructve puncture tests were not delverng suffcent nformaton on softenng behavour, a wth low frut numbers a non-destructve test allowed better montorng of softenng of frut wth tme. As shrvellng occurred n prelmnary experments a was common across a number of selectons examned, methods of both assessng degree of shrvellng a methods to amelorate t (e.g., retenton of a pedcel, packagng varatons) were examned n the experments. Shrvel was assessed vsually on a scale 0-3 where refers to shrvel beng barely notceable a occurrng only at the e of the frut that softens frst, 2 refers to suffcent shrvel to be seen by a lkely to be unacceptable to consumers a occurrng at least halfway up the frut, 3 refers to shrvel coverng the entre frut a would be unacceptable to consumers. Ethylene a CO 2 measurements were made by staard gas chromatography after samplng the punnets at regular ntervals through a gas tght seal. RESULTS AND DISCUSSION Flowerng There appeared to be lttle seasonal dfference n the rankng of selectons for tmng of flowerng. The frst flowers of the selectons flowerng earlest (e.g., E3H6) opened on 7 or 8 November a the frst flowers of the latest selectons (e.g., J5F3) on 6 or 22 November n 994 a 995 respectvely. The man flush of flowerng occurred 4-5 days earler n

6 Hassall et al. Evaluaton of Actnda arguta Tme (DAA) Tme (DAA) Fg. Growth of Actnda arguta selectons durng the 995/96 season for calbraton of regresson curves. A, longfruted K3 length ( ) a two dameters (, A); B, apple-shaped frut K2D4 length ( ) a two dameters (, A); C, growth rate of K.3I ; a D, growth rate of K.2D4. (All data ponts have not been cated to mprove clarty.) Data based on 0 replcate frut. (DAA = days after anthess.) 994 than n 995. Most selectons showed a short perod of flower openng of about 0 days, smlar to that of the commercal kwfrut A. delcosa (Hoppng 990). In contrast, flowerng n J5I3 took place over at least 23 days (data not shown). Frut growth In all selectons, 80% offrut growth occurred wthn c. 40 days after anthess (DAA, Fg. ), regardless of the shape of the frut or ts fnal frut sze. Maxmum growth rates occurred DAA across all selectons, a ranged from 65 to 550 mm 3 /day. Between seasons, the relatve value of the maxmum growth rate a date of maxmum growth rates was consstent among selectons (Table 3). Frut wth an oval shape teed to have a hgher maxmum growth rate than frut wth a rou shape (Fg., Table 3), a also teed to be larger. Durng the frst 40 DAA, frut grew more n length than n dameter n both oval a rou frut (Fg. ). From then on, oval frut grew more n dameter than n length. There was a seco peak n growth rate between 50 a 80 DAA (Fg. ). After ths, growth contnued at a low rate untl frut softened on the vne. Most growth n A. arguta was completed by 40 DAA, whereas 80 DAA were requred for kwfrut (Snelgar et al. 992; Tombes et al. 994). The two peaks n growth rate were more clearly demonstrated n A. arguta types than n A. delcosa 'Hayward'. The double sgmod pattern typcal of grape (Kanells & Roubelaks-Angelaks 993), whch also rpens on vne before harvest, was not observed.

7 00 New Zeala Journal of Crop a Hortcultural Scence, 998, Vol. 26 Frut maturaton Colour All selectons had skn a flesh throughout frut growth. There was no colour change durng maturaton n the frut (data not shown). Table 3 Calculated frut growth rates n 995 a 996 seasons for Actnda arguta a A. arguta x A. melanara seedlngs based on regresson equatons generated from correlatons between dameter a length measurements a fresh weghts. (DAA = days after an thess.) Selecton AA0_0 AA02_0 AAll_0 (Issa) J5I3 J5H3 K2D4 M4F6 E3H6 E4I6 K3I J5F3 K.6H5 Tme of maxmum growth rate (DAA) 995(996) (26) 32 (32) (26) 32 25(8) Value of maxmum growth rate (mm 3 /day) 995(996) (65) 240 (250) (295) (550) Selectons wth red skn a/or flesh changed colour 73 DAA (K6H5) a 09 DAA (E4I6 a J5F3). Reddenng occurred at the e of the frut that softened frst a the tmng of red colour development was consstent among selectons between seasons (data not shown). Seeds Seed colour changed from lght to dark durng the seco peak (50-80 DAA) n growth rate (Table 4). Complete coloraton took place over 4-39 days n the 994/95 season a days n the 995/96 season. All seeds n all selectons were dark by 98 DAA, as frut growth rates reduced to a mnmum. Hence the perod between seed maturaton a harvest (0% soft frut) vared sgnfcantly between selectons. DMaSSC DM n md January for the selectons studed were generally lower n 996 than n 995, rangng from 4.5 to 8.7% n the 995 season a 0.7 to 6.8% n the 996 season. J5F3 had the lowest a J5H3 the hghest DM at ths tme n both seasons. DM ncreased as frut matured (Fg. 2 a 3), accumulaton plateaued n some selectons, but n 996 n partcular, DM contnued to ncrease n many selectons as frut rpened on the vne. The tmng of the plateau vared between selectons, rangng from c. 60 DAA (K3I) to 20 DAA (J5H3). Frut of E4I6, Table 4 Maturaton parameters fox Actnda arguta selectons n 995 a 996. Seed coloraton s frst compared as the number of days between the frst day dark seeds were observed to the day where all seeds were dark; seco as the number of days after anthess when all seeds were dark. (SSC = soluble solds concentratons; DM = dry matter; DAA = days after anthess; data from measurements of 0 vdual frut per selecton sampled sequentally throughout the growng season; = not done.) Seed coloraton 0-00% (days) 995/996 00% mature (DAA) 995/996 SSC Tme of rapd ncrease (DAA) DM Tme to plateau (DAA;) Softenng Tme to 0% soft frut (DAA) AA0 0 AA02 0 AA3 0 J53 J5H3 K2D4 M4F6 E3H6 E4I6 K3 J5F3 K6H5 39/ 29/ 39/ 35/28 23/3 30/38 30/28 4/28 23/28 30/28 30/3 23/28 98/ 95/ 9/ 98/94 85/96 92/97 9/92 87/9 88/95 94/96 92/87 94/

8 Hassall et al. Evaluaton of Actnda arguta Tme (DAA) Tme (DAA) Fg. 2 Increase n soluble solds concentratons (A) a dry matter concentraton ( ) n representatve Actnda arguta selectons durng frut maturaton a on-vne rpenng n 995. A, K3G; B, J4D4; C, K3I; a D, J5H3. Data are means of 0 frut replcates, SEM vared by <5%. E3H6, K3G, a J4D4 showed a contnuous ncrease n DM durng maturaton, untl 0% of frut were soft (Fg. 2, data not shown). There was remarkably lttle dfference between frut from flowers that opened near the begnnng of the flush of flowerng, a those that opened towards the e n both selectons examned. Wth a gap of days between early a late flowers n both J5H3 a J5I3, SS a DM levels for the same calear date were very smlar, but there was a teency for frut from late flowers to have a slghtly hgher DM on the same DAA compared to frut from early flowers (Fg. 3). In md January of both seasons, t was dffcult to get suffcent juce to obtan a readng on a refractometer because of vscosty of the juce. Average SSC of all selectons at ths tme ranged from 4.2 to 5.% a 3.5 to 4.5% for 995 a 996 respectvely. As frut matured, a slow ncrease n SSC changed to become a rapd ncrease (Fg. 2 a 3). At varyng lengths of tme after ths change frut became soft on the vne (Table 4). The tmng of the change n SSC fell between 2 February (K6H5) a 7 March (K3G, 996), but n all nstances the tmng was smlar to that of seed maturaton, or after seed maturaton. Frut of M4F6 were the excepton, wth both SSC a DM contnung to ncrease at a steady rate untl frut were soft (data not shown). DM at harvest ranged between 5.6 a 24.0 depeng on selecton a season (Table 5). In both seasons, frut of J5H3, J5I3, K2D4, M4F6, J5F3, a K6H5 all had smlar DM a SSC concentratons at the same number of DAA (data not shown). In frut of E3H6, K3I, a E4I6 the rapd rse n SSC occurred earler n 996 than n 995, although total DM was smlar (data not shown). In A. delcosa 'Hayward', frut maturty s judged to occur as DM plateaus a a rapd ncrease n soluble sugars occurs (Beever & Hopkrk 990). Ths generally occurs as the clmate becomes cooler n autumn, a controlled experments have demonstrated that rasng or lowerng the temperature durng ths perod delays or encourages a rapd ncrease n soluble solds concentratons (Hopkrk et al.

9 02 New Zeala Journal of Crop a Hortcultural Scence, 998, Vol. 26 S U0 60 Tme (DAA) Fg. 3 Soluble solds concentratons (,A) a dry matter concentraton (O, A) durng frut maturaton n frut from early (, O) or late ( A, A) flowers n Actnda arguta selectons: A, J5H3; a B, J5I3. Data are means of 0 replcate frut, SEM <5% of mean. Table 5 Dry matter (DM) a soluble solds concentraton (SSC) at harvest (5-0% of frut soft) of Actnda arguta selectons. Data are means of three replcates for DM a 0 replcates (SSC). ( = not done.) AA0 0 AA020 AA 0 J5I3 J5H3 K2D4 K3E5 J3I2 K3G K2EI M4F6 K3G2 K.6G C3C3 E3H6 E4I6 K3 J4D4 J5F3 K.6H DM (<Vo) SSC( %) ). The equvalent concept does not easly apply to frut of A. arguta types. There was wde varaton between selectons n the pattern of DM accumulaton a the total amount. Ths s mportant n terms of assessng frut maturty a applyng knowledge from one speces to another. If selectons have dfferent behavours wth respect to DM a sugar accumulaton then these parameters are unlkely to be useful n maturty assessments. The pattern also vared between seasons, a carbohydrate often contnued to accumulate untl 5-0% of frut were soft. However selectons remaned smlar n the relatve quantty of DM accumulated between seasons. The length of tme requred for accumulaton of DM also vared between selectons, e.g., the slowest accumulator also had the slowest growth rate a the fastest accumulator (K3I) has the greatest growth rate of the frut measured. A dfference n on-vne rpenng among selectons was also observed by Kabaluk et al. (997) where they classfed Tssa' as a late "maturng" selecton, requrng 5 months from flowerng to rpeness. Frut of Tssa' n New Zeala, however, requred c. 3 months to rpen on the vne, probably catng a major effect of clmate or envronment, as other selectons n our study requred nearly 5 months n the same season. Klages et al. (998) analysed frut of two selectons for sugar a starch content n parallel wth our study. When comparng J4D4 (K. Klages unpubl. data), J5H3, a J5I3 (Klages et al. 998), t was apparent that an ncrease n sucrose generally concded wth the loss of starch a ncrease n SSC, but the tmng of ths occurred before the maxmal accumulaton of DM. For example, n J4D4 the starch to sucrose converson occurred at a DM of 8.5% (maxmal accumulaton of 23%), at 6% DM for J5I3 (maxmal 23%), a 22% DM for J5H3 (maxmal 25%). These results cate a contnung mport of sgnfcant amounts of sugar from the vne once starch accumulaton has ceased, unlke the stuaton n kwfrut (Beever & Hopkrk 990; MacRae & Redgwell 990). Based on the experence wth 'Hayward'(MacRae et al. 989), the contnued mport of sugar nto the frut wll have an mpact on assessment of frut maturty a flavour preference. Frut frmness There was consderable varaton among selectons n frut puncture frmness n md January (60-72 DAA). For example, E4I6 at 67 DAA had a mean frut frmness of 9.5 N, whereas J5H3 at 67 DAA had a mean frut frmness of 4.0 N. There was a

10 Hassall et al. Evaluaton ofactnda arguta 03 slow decrease n frut frmness untl between md February a late March. At ths tme (depeng on selecton) there was more rapd softenng as the frut began to rpen on the vne. Frut of J5I3 were the quckest to soften, takng 4 days to soften from a mean of.4 to.07 N. Frut of M4F6 were the slowest to soften, takng 7 days to drop from.2 to.96 N. SSC vared between 5.7 a 0% at the tme when 0% of frut were soft across both seasons (Table 5). Some selectons (E4I6, K.3G) softened from the stem e down a others from the stylar e up (J4D4, K6H5). Rapd softenng from frm to eatng rpeness cates a potental problem when determnng harvest maturty. The short tme-frame allows for very lttle error n tme n decdng when to harvest, especally f the rate of ncrease n SSC s examned (J5I3). Unlke commercal kwfrut, there was no large change n rate of ncrease n SSC, or n any oder character measured, that mght reflect such rapd softenng. The dfferental softenng/colourng has also been observed to occur n strawberry, but ths phenomenon has generally not been well documented. A prevous assessment of how A. arguta frut soften usng puncture tests (Jackson & Harker 997) cated that softenng occurred wth a longtudnal gradent (n selectons K3I2 a K3J5) wth the stem e frmer than the dstal e. Maturty cators The contnued ncrease n DM after or wthout a sharp rse n SSC as frut rpen on the vne cates that the staard methods for assessng maturty n commercal kwfrut may not be applcable to A. arguta types. When the speces hybrd 'Kr' ((A. delcosa x A. arguta) x A delcosa) was examned (Whte & Beatson 993), t was noted that the DM contnued to ncrease as the rapd rse n SSC occurred. It s clear from our data that ths s lkely to be a contrbuton from the A. arguta parentage. Smlarly the characterstc of rapd frut softenng on the vne a rapd softenng n postharvest storage were also noted to occur n ths hybrd, a are characterstc of the A. arguta selectons examned here. Coloraton (n those selectons that redden) occurs too late n frut softenng to be of value as a maturty cator. If the tme after seeds reach maturty s examned, then n 995 there were between 4 a 73 days untl a rapd SSC ncrease depeng on selecton (values after the seco growth rate peak were smlar) a between 4 a 26 days untl the DM plateaued. Comparable values n 996 for the same selectons were between 0 a 0 days untl the SSC ncrease, a between 4 a 40 days untl the DM plateau. The seasonal varaton therefore makes SSC a DM also unlkely to be useful as cators of harvest tme. Frut storage Durng storage the two methods of measurng frmness (puncture a compresson) showed smlar tres n softenng (Fg. 4), but the compresson test was more nformatve. As a non-destructve test t also allowed contnual assessment of the same frut. For all selectons, c. 90% of softenng a ncrease n SSC occurred durng the frst 3 weeks of storage (Fg. 4 a 5). Soft frut ( N at harvest) stored for up to 2 weeks at 0 C (data not shown), a frm frut for at least 6 weeks at 0 a 3 C (Fg. 4). Once the frut were soft, there was lttle dfference n frut characterstcs between the two temperatures studed. 'Issa' was unusual n dsplayng a dfferent rate of softenng between the 0 a 3 C storage temperatures, remanng frmer at 0 C for longer (Fg. 4). Kempler et al. (995) stored a small range of selectons of A. arguta at C for 7 days, ncludng 'Issa', but dd not dstngush 'Issa' from the other selectons n ths study. When frut were rpe ( N), the stalks were brown a shrvelled n frut of all selectons. There was lttle or no evdence of storage rots, or damage to the frut at ether temperature, or n frut held n or out of punnets (data not shown). If rots appeared, t was only after 6 weeks of storage. The only dsorders noted were the presence of pttng n selecton K2D4. Ths frst appeared c. 2 weeks after transfer to 0 C. Kempler et al. (995) also dd not observe storage dsorders or dsease n ther study, but warned of CO2 damage wth rased temperatures or lack of adequate ventlaton. However pttng was not a reported form of damage n ther study, although t has been assocated wth chllng njury n other fruts (Wang 993), a may cate that ths selecton s less cold tolerant than others. Frut shrvel In Experment where frut were held n trays, slght levels of shrvellng (water loss) occurred n all selectons except K3I after 6 weeks of storage (data not shown). Shrvellng was more notceable n frut stored at 3 C than at 0 C. In Experment 2 the same was observed, where shrvel was more severe at 3 C. However weght loss by the frut at 3 C was approxmately half that at 0 C (P < 0.05), mplyng that

11 04 New Zeala Journal of Crop a Hortcultural Scence, 998, Vol Tme after harvest (weeks) Tme after harvest (weeks) Fg. 4 Loss of frut fnnness n Actnda arguta selectons durng storage at 0 C (A) or 3 C ( ) usng ether puncture tests (left ha graphs) or compressve tests (rght ha graphs). A, K3 ; a B, 'Issa'. water loss s not the only component nvolved n weght loss. If frut stored at 0 C, wth or wthout stalks, were compared (Experment 2), there was no detectable dfference n shrvel. However after 6 weeks of storage at 3 C, frut wth stalks had more shrvel (.8 cf..0). Weght loss dd not reflect ths result. K3E5 held at 0 C, showed no sgnfcant dfference n weght loss wth or wthout stalks. K6G showed sgnfcantly (P < 0.0) greater weght loss wthout stalks than wth when stored at 3 C. If frut were stored n punnets wth perforatons (Experment 2) then weght loss was greater (5.0% cf. 6.%) but the dfference was not sgnfcant n ths nstance. In Experment 3 shrvellng ncreased slghtly durng storage at 0 C, then doubled durng shelf lfe (Table 6). As much as 0% of the frut weght was lost when frut were held at 20 C (Fg. 6), a enclosng the frut n punnets reduced ths sgnfcantly (P < 0.00). As frut remaned n coolstorage for longer perods, the amount of shrvel n rpe frut after storage was reduced, but shelf lfe tself was also reduced (as cated by frut frmness). Weght loss a shrvel do not correlate hghly, e.g., 0% loss of weght at 20 C n K2D4 but only 0.6 as a shrvel score compared to 6% weght loss at 20 C after storage but a shrvel score of.6. It may be that weght loss at 20 C also represents a sgnfcant proporton of loss of carbohydrate through respraton, as well as that lost as water. Frut colour Harvestng frut altered the rate of colour development, such that when frut are rpened at 20 C the amount of red coloraton was less than that of frut on the vne (data not shown). Placng the frut at low temperatures also nterrupted colour development (Table 6), such that when frut were rpe after exteed perods n storage, reddenng (ncrease n Hue angle) was reduced.

12 Hassall et al. Evaluaton of Actnda arguta I 2 M S 0 ^ B v - I 8 ' x 6, 4 2 n Tme (weeks) Tme (weeks) Fg. 5 Loss of frut frmness usng puncture tests ( ) a ncrease n soluble solds concentratons (V) n frut of Actnda arguta selectons durng postharvest storage at 0 C. Data are means of 0 replcate frut a SEM <5% of mean. A, K3I; B, 'Issa'; C, J5H3; a D, K2D4. Table 6 Softenng a shrvel n three Actnda arguta selectons durng postharvest storage a subsequent shelf lfe, a development of redness n one selecton (hgher hue angle denotes greater redness). Data are means of 20 frut per assessment, ( = not done.) Shelf lfe Storage Shelf lfe Storage Shelf lfe Storage Shelf lfe Selecton Harvest (7 days) (25 days) (5 days) (35 days) (2 days) (42 days) (3 days) J4D4 Frut frmness (N) Shrvel (score 0-5) J5F3 Frut frmness (N) Shrvel (score 0-5) Colour (hue) K2D4 Frut frmness (N) Shrvel (score 0-5) Ethylene a CO2 concentratons If frut were held n punnets wthout perforatons ethylene a CO 2 accumulated when frut were at 20 C (Fg. 7). If punnets had perforatons, nether ethylene nor CO 2 accumulated to any degree. No sgnfcant accumulaton of ether gas was noted at 0 C.

13 06 New Zeala Journal of Crop a Hortcultural Scence, 998, Vol A 0 D Weght los (X) t t _ ^ - 4 (X) Weght loss Wegltt loss (X) f '! o I I f 9 B y r J Tme (days) 0 < < I A c loss (: Weght ! "<p 0 Â Tme (days) _ ^ J / Fg. 6 Weght loss from frut of Actnda arguta selectons n punnets durng storage at 0 C ( ) a shelf lfe at 20 C ( ). Sold symbols cate value durng storage, open symbols cate values durng shelf lfe; symbol changes wth each removal from storage. A, J5H3; B, J4D4; C, K2D4; a D, K2D4 (sold symbols represent weght loss of frut not wthn punnets, a open symbols weght lossfromfrutwthn punnets). Data are means of three replcate punnets a SEM vared by <5%. CONCLUSIONS Actnda arguta crosses of dfferng genetc backgrou showed some remarkably smlar characterstcs, many of whch were also common to the commercal kwfrut, Actnda delcosa 'Hayward'. These were the generally short duraton of the flowerng perod, the frut growth pattern (albet of a shorter duraton n A. arguta than n A. delcosa), maturaton of seeds after the man growth flushes, the accumulaton of DM a a rapd ncrease n SSC, a the lack of storage dsorders at 0 C. Key dfferences to commercal kwfrut were n the rapd onvne softenng, contnued sugar mport a DM accumulaton as starch s lost, the short storage lfe, a frut shrvel. A key factor n commercal development of A. arguta types wll be a relable cator of harvest maturty. DM accumulaton a DM/SSC changes as used n A. delcosa types are unlkely to be suffcent as shown by the contnued mport of sugar/ DM seen n some A. arguta selectons, a

14 Hassall et al. Evaluaton of Actnda arguta a> : LU 0. - / J. t é! Ú! 7 A methods to enhance postharvest reddenng, the red A. arguta wll be a short perod, local market or ar freght specalst fresh frut. ACKNOWLEDGMENTS Ths work was fued by the New Zeala Fouaton for Research Scence a Technology (CO 630, CO6620). Zespr Internatonal (formerly NZKMB) contrbuted to the postharvest research reported here. We would also lke to thank Karn Klages a Helen Donnson for access to unpublshed data; Kevn Patterson for help wth the growth analyses; a Annette Rchardson, Anne Whte, a Ross Ferguson for useful comments on the manuscrpt. REFERENCES ü Tme (days) Fg. 7 Ethylene a CO 2 concentratons n punnets of Actnda arguta selecton K2D4 durng storage at 0 C (closed symbols) a shelf lfe at 20 C (open symbols; symbols change accordng to tme n storage before removal to 20 C). Data are means of three punnets a SEM prevously reported for a hybrd between A. delcosa wad A. arguta (Whte & Beatson 993). Compresson tests are clearly the method of preference n assessng frmness of A. arguta. The two major problems assocated wth postharvest storage of the frut of selectons examned were shrvel a poor coloraton. Control of water loss n the frut by storage technques wll therefore be crucal n establshng commercal sales of ths speces. For those frut that turn red, there s an addtonal problem assocated wth harvestng a postharvest lfe of the frut. For example, red frut wll need to be harvested when red or nearly completely red, whch wll result n the harvest of soft frut. In turn these frut have a maxmum postharvest storage lfe at low temperature of 2 weeks (uer staard cotons), wth lttle or no shelf lfe followng ths. Hence unless alternatve postharvest technologes can be used, or Beever, D. J.; Hopkrk, G. 990: Frut development. In: Warrngton, I. J.; Weston, G. C. ed. Kwfrut scence a management. Ray Rchards Publsher. Pp Clayton, C. M. 996: Frut growth a development of Actnda chnenss (Planch.). Unpublshed Masters thess, School of Bologcal Scences, Unversty of Auckla, New Zeala. Ferguson, A. R. 990: The Genus Actnda. In: Warrngton, I. J.; Weston, G. C. ed. Kwfrut scence a management. Ray Rchards Publsher. Pp Hassall, A. K.; Prngle, G.; Bon, L. M.; Hale, C. 995: Growth, maturaton a storage of Actnda arguta. In: Proceedngs Australasan Postharvest Hortculture Conference, 8-22 September, Melbourne. P. 23 (Abstract). Hopkrk, G.; Snelgar, W. P.; Home, S. F.; Manson, P. J. 989: Effect of ncreased preharvest temperature on frut qualty of kwfrut (Actnda delcosa). Journal of hortcultural scence 64: Hoppng, M. 990: Floral bology. In: Warrngton, I. J.; Weston, G. C. ed. Kwfrut scence a management. Ray Rchards Publsher. Pp Jackson, P. J.; Harker, F. R. 997: Changes n frmness of the outer percarp, nner percarp, a core of Actnda speces durng rpenng. New Zeala journal of crop a hortcultural scence 25: Kabaluk, J. T.; Kempler, C.; Tovonen P. M. A. 997: Actnda arguta characterstcs relevant to commercal cultvaton. Frut varetes journal 5: Kanells, A. K.; Roubelaks-Angelaks, K. A. 993: Grape. In: Seymour, G.; Taylor, J.; Tucker, G. ed. Bochemstry of frut rpenng. Loon, Chapman a Hall. Pp

15 08 New Zeala Journal of Crop a Hortcultural Scence, 998, Vol. 26 Kempler C.; Kabaluk, J. T.; Tovonen, P. M. A. 995: Harvestng a halng frut of Actnda arguta experments wth ethylene gas. Agrculture a Agr-food Canada techncal bulletn no. 2. Klages, K.; Donnson, H.; Boldngh, H.; MacRae, E. 998: myo-inostol s the major sugar n Actnda arguta durng early frut development. Australan journal of plant physology 25: Lallu, N.; Searle, A. N.; MacRae, E. A. 989: An nvestgaton of rpenng a halng strateges for early season kwfrut (Actnda delcosa cv, Hayward). Journal of the scence of food a agrculture 47: MacRae, E. A.; Bowen, J. H.; Stec, M. G. H. 989: Maturaton of kwfrut (Actnda delcosa cv Hayward) from two orchards: dfferences n composton of the tssue zones. Journal of the scence of food a agrculture 47: MacRae, E. A.; Redgwell, R. J. 990: Parttonng of 4 C- photosynthate n developng kwfrut. Scenta hortculturae 44: McGure, R. G. 992: Reportng of objectve colour measurements. HortScence 27: Snelgar, W. P.; Manson, P. J.; Martn, P. J. 992: Influence of tme of shadng on flowerng a yeld of kwfrut vnes. Journal of hortcultural scence 67: Tombes, A.; Antognozz, E.; Pallott, A. 994: Optmum leaf area ex n T-bar traned kwfrut vnes. Journal of hortcultural scence 69: Wang, C. Y. 993: Approaches to reduce chllng njury of fruts a vegetables. Hortcultural revews 75: Whte A.; Beatson, R. 993: Evaluaton of a new kwfrut hybrd. Proceedngs of the Australasan Postharvest Conference. Pp