Chromosome doubling has been widely explored as a bridge to help gene introgression between different ploidy levels both between and within species for crop improvement (Hayward et al., 1993; Meru, 2012; Wu et al., 2011). Both fruit and seed are often larger after chromosome doubling (Campos et al., 2009; Wu et al., 2012; Ye et al., 2010). However, very little information has been available on the effects of increasing ploidy level on other attributes of fruit quality considered important in crop improvement.
Actinidia Lindl. (kiwifruit) species have only relatively recently been introduced into cultivation and grown as commercial crops. Most kiwifruit produced are consumed fresh (Ferguson, 2009), so returns to producers depend on the prices obtained for the fresh fruit. Factors influencing fruit price include total supply, season of supply, cultivar and, most important, fruit quality.
Fruit quality in kiwifruit has many components such as fruit size, shape, flesh texture, color, flavor, firmness, DM, SSC, vitamin C content, core size, and skin color and thickness. Further expansion of the kiwifruit industry will require the development of new cultivars with enhanced sweetness, flavor, and storage life and a variety of flesh colors (Ferguson and Seal, 2008) as well as optimum fruit quality with easy handling during field management and harvesting, packing, storage, and marketing.
In this article, we compare some aspects of fruit quality in some diploid selections of Actinidia chinensis with those of fruit from autotetraploids produced by colchicine-induced chromosome doubling. Our aim was to determine the effects of increasing the number of genomes on fruit quality and development using a number of easily measured attributes. During fruit development, SSC at harvest is an indicator of fruit maturity, and DM content reflects the potential SSC at eating ripeness once starch reserves have been converted to sugar (Burdon et al., 2004; Feng et al., 2011). Flesh firmness can also be used to assess fruit maturity and storage ability. One of the selections studied was ‘Hort16A’ and autotetraploids derived from it. As fruit of ‘Hort16A’ mature, the flesh color changes from green to yellow, and flesh hue angle (ho) is one of the key parameters used to determine the quality and maturity of its fruit because the color appeals greatly to consumers. The three other selections studied came from a program to develop kiwifruit with red flesh: the extent and intensity of red pigmentation are important parameters for assessing quality in these selections. These various quality attributes were used to assess the possible commercial potential of the different selections and the autotetraploid plants derived from them.
Belrose, Inc 2009 World kiwifruit review. 2009 Ed. Belrose, Inc. Publishers, Pullman, WA
Burdon, J., McLeod, D., Lallu, N., Gamble, J., Petley, M. & Gunson, A. 2004 Consumer evaluation of ‘Hayward’ kiwifruit of different at-harvest dry matter contents Postharvest Biol. Technol. 34 245 255
Campos, J.M.S., Davide, L.C., Salgado, C.C., Santos, F.C., Costa, P.N., Silva, P.S., Alves, C.C.S., Viccini, L.F. & Pereira, A.V. 2009 In vitro induction of hexaploid plants from triploid hybrids of Pennisetum purpureum and Pennisetum glaucum Plant Breed. 128 101 104
Cheng, C.H., Seal, A.G., Murphy, S.J. & Lowe, R.G. 2007 Red-fleshed kiwifruit (Actinidia chinensis) breeding in New Zealand Acta Hort. 753 139 146
Cheng, Z.-Q., Liu, W.-G., Liu, Z.-M., Yan, Z.-H., Zhao, S.-J., He, N. & Zhang, J.-J. 2008 Comparison of vitamin C contents in watermelon fruits with different ploidy J. Fruit Sci. 25 760 763
Cui, Z.-X. 1993 Zhongguo Mihoutao [Kiwifruit in China]. Shandong Science and Technology Publisher, Jinan, China
Deutsch, M.J. 1996 Vitamins and other nutrients. 45.1.14. AOAC Official Method 967.21. Ascorbic acid in vitamin preparations and juices. 2,6-Dichloroindophenol titrimetric method. 45:16–17. In Cunniff, P. (ed.). Official methods of analysis of AOAC International. 16th Ed. AOAC International, Gaithersburg, MD
Feng, J., McGlone, A.V., Currie, M., Clark, C.J. & Jordan, B.R. 2011 Assessment of yellow-fleshed kiwifruit (Actinidia chinensis ‘Hort16A’) quality in pre- and post-harvest conditions using a portable near-infrared spectrometer HortScience 46 57 63
Ferguson, A.R. & Seal, A.G. 2008 Kiwifruit, p. 235–264. In: Hancock, J.F. (ed.). Temperate fruit crop breeding: Germplasm to genomics. Springer, Dordrecht, The Netherlands
Ferguson, A.R., Zhang, J.-L., Duffy, A.M., Beatson, R.A., Cheng, C.-H., Datson, P.M., Lowe, R.G., McNeilage, M.A., Harris-Virgin, P.M., Seal, A.G. & Wu, J.-H. 2009 Ploidia e uso della citometria a flusso nel miglioramento genetico dell’actinidia Italus Hortus 16 5 78 83
Harker, F.R., Carr, B.T., Lenjo, M., MacRae, E.A., Wismer, W.V., Marsh, K.B., Williams, M., White, A., Lund, C.M., Walker, S.B., Gunson, F.A. & Pereira, R.B. 2009 Consumer liking for kiwifruit flavour: A meta-analysis of five studies on fruit quality Food Qual. Prefer. 20 30 41
Hayward, M.D., Bosemark, N.O. & Romagosa, I. 1993 Plant breeding—Principles and prospects. Chapman & Hall, Cambridge, UK
Jaeger, S.R., Harker, R., Triggs, C.M., Gunson, A., Campbell, R.L., Jackman, R. & Requejo-Jackman, C. 2011 Determining consumer purchase intentions: The importance of dry matter, size and price of kiwifruit J. Food Sci. 76 S177 S184
Liu, Q.-Z., Yuan, K.-J., Zhang, L.-S., Zhao, H.-J., Liu, P. & Han, Z.-H. 2006 Growth and fruit characteristics of autotetraploid plants of Royal Gala apple J. Fruit Sci. 23 102 104
Luo, Y.-W., Qiao, Z.-J., Zhu, Z.-Y., Huangpu, Z.-S. & Chang, J.-H. 1997 Study on autotetraploid grape cv. Muscat Hamburg with good quality Acta Hort. Sin. 24 125 127
McGhie, T.K. & Ainge, G.D. 2002 Color in fruit of the genus Actinidia: Carotenoid and chlorophyll compositions J. Agr. Food Chem. 50 117 121
Meru, G. 2012 Polyploidy. In: Brummer, C. and C. McGregor (eds.). Plant breeding in the 21st century. PBGG, University of Georgia, Athens, GA. 16 Jan. 2013. <http://projects.coe.uga.edu/plantbreeding/index.php?title=Main_Page>
Minchin, P.E.H., De Silva, N., Snelgar, W.P., Richardson, A.C. & Thorp, T.G. 2003 Modelling of colour development in the fruit of Actinidia chinensis ‘Hort16A’ N. Z. J. Crop Hort. Sci. 31 41 53
Monastra, F. & Testoni, A. 1992 Horticultural performance and quality characteristics of fruit from kiwifruit plants (cv. Hayward) obtained by in-vitro propagation, by cuttings and by grafting Acta Hort. 297 197 203
Montefiori, M., McGhie, T.K., Hallett, I.C. & Costa, G. 2009 Changes in pigments and plastid ultrastructure during ripening of green-fleshed and yellow-fleshed kiwifruit Sci. Hort. 119 377 387
Nukaya, T., Yahata, M., Suzuki, K., Yasuda, K., Kunitake, H., Komatsu, H., Mukai, H., Harada, H. & Takagi, T. 2009 Fruit characteristics in autotetraploid Meiwa kumquat induced by colchicine treatment to nucellar embryos Hort. Environ. Biotechnol. 50 188 190
SAS Institute Inc 2000–04 SAS 9.1.3 help and documentation. SAS Institute Inc. Cary, NC
Sugiyama, S.I. 2005 Polyploidy and cellular mechanisms changing leaf size: Comparison of diploid and autotetraploid populations in two species of Lolium Ann. Bot. (Lond.) 96 931 938
Van Laere, K., Franca, S.C., Vansteenkiste, H., Van Huylenbroeck, J., Steppe, K. & Van Labeke, M.-C. 2011 Influence of ploidy level on morphology, growth and drought susceptibility in Spathiphyllum wallisii Acta Physiol. Plant. 33 1149 1156
Viehmannová, I., Trávíčková, M., Špatenková, E., Černá, M. & Trávníček, P. 2012 Induced polyploidization and its influence on yield, morphological, and qualitative characteristics of microtubers in Ullucus tuberosus Plant Cell Tissue Organ Cult. 109 83 90
Woodward, T.J. & Clearwater, M.J. 2008 Relationships between ‘Hayward’ kiwifruit weight and dry matter content Postharvest Biol. Technol. 48 378 382
Wu, J.-H., Ferguson, A.R. & Murray, B.G. 2011 Manipulation of ploidy for kiwifruit breeding: In vitro chromosome doubling in diploid Actinidia chinensis Planch Plant Cell Tissue Organ Cult. 106 503 511
Wu, J.-H., Ferguson, A.R., Murray, B.G., Jia, Y., Datson, P.M. & Zhang, J. 2012 Induced polyploidy dramatically increases the size and alters the shape of fruit in Actinidia chinensis Ann. Bot. (Lond.) 109 169 179
Ye, Y.M., Tong, J., Shi, X.P., Yuan, W. & Li, G.R. 2010 Morphological and cytological studies of diploid and colchicine-induced tetraploid lines of crape myrtle (Lagerstroemia indica L.) Sci. Hort. 124 95 101