DOI QR코드

DOI QR Code

배나무(Pyrus spp.) 유전체 연구 현황

Researches of pear tree (Pyrus spp.) genomics

  • Oh, Youngjae (Department of Horticulture, Chungbuk National University) ;
  • Shin, Hyunsuk (Department of Horticulture, Chungbuk National University) ;
  • Kim, Keumsun (Department of Horticulture, Chungbuk National University) ;
  • Han, Hyeondae (Department of Horticulture, Chungbuk National University) ;
  • Kim, Yoon-Kyeong (Pear Research Institute, National Institute of Horticultural & Herbal Science, Rural Development Administration) ;
  • Kim, Daeil (Department of Horticulture, Chungbuk National University)
  • 투고 : 2015.12.16
  • 심사 : 2015.12.27
  • 발행 : 2015.12.31

초록

배나무는 원산지와 분화방향에 따라 유럽, 미국, 호주 등에서 주로 재배되는 서양배와 중국, 일본, 한국 등 동남 아시아 지역을 중심으로 분포 및 재배되고 있는 동양배로 구분된다. 17개의 기본염색체를 가진 배나무는 대부분 이배성(2n=2x=34)이며, 단일 S 유전자좌에 의해 조절되는 자가불화합성과 과수 작물의 주요 특징인 유년성으로 인해 유전 연구 및 정밀한 품종 육성에 큰 제한을 받고 있다. 배나무속 식물의 유전연구는 분자생물학 관련 기술의 발달로 다양한 형태의 분자 표지의 개발이 이루어짐과 동시에 유연관계분석, 유전자지도작성, QTL 분석과 같은 다양한 유전연구에 활발히 이용되었다. 또한 배나무의 유전자지도는 병 저항성이나 다양한 유용형질과 연관된 QTL 확인을 위한 연구로 이어지고 있다. 대량 병렬 반응 및 다중처리를 토대로 획기적인 염기서열 분석 비용의 감소를 이뤄낸 NGS 기술은 대용량, 고효율, 저비용으로 식물 유전체 해독을 가능하게 하여, 중국배 'Danshansuli'와 유럽배 'Bartlett'에서 유전체 분석이 완료되었다. 최근 국내에서는 황금배, 청실리 및 미니배의 resequencing 및 GBS를 통한 SNP 탐색 등의 연구를 통해 화기, 숙기 당도 등 농업적으로 유용형질에 대한 게놈전체 연관분석을 수행하고 있다.

Based on the place of its origin, pear tree (Pyrus spp.) is largely divided into European pears (P. communis, cultivated mainly in Europe and the U.S.) and Asian pears (P. pyrifolia, P. bretschneideri, and P. ussuriensis, distributed and grown in East Asian countries including China, Japan, and Korea). Most pear trees have 17 chromosomes (diploidy, 2n=2x=34). Their genetic studies and precise cultivar breeding are highly restricted by conditions such as self-incompatibility controlled by S-locus and juvenility as one major character of fruit crops. Genetic studies on Pyrus have been promoted by the development of various molecular markers. These markers are being utilized actively in various genetic studies, including genetic relationship analysis, genetic mapping, and QTL analysis. In addition, research on pear genetic linkage maps has been extended to studies for the identification of QTL for target traits such as disease resistance and genetic loci of useful traits. NGS technology has radically reduced sequencing expenses based on massive parallel reactions to enable high-capacity and high-efficiency. NGS based genome analyses have been completed for Chinese pear 'Danshansuli' and European pear 'Bartlett'. In Korea, GWAS for agricultural valuable traits such as floral structure, ripening, and total soluble contents have been conducted through resequencing. GBS has been performed for 'Whangkeumbae', 'Cheongsilri', and 'Minibae'.

키워드

참고문헌

  1. Altshuler D, Daly MJ, Lander ES (2008) Genetic mapping in human disease. Science 322:881-888 https://doi.org/10.1126/science.1156409
  2. Atwell S, Huang YS, Vilhjalmsson BJ, Willems G, Horton M, Li Y, Meng D, Platt A, Tarone AM, Hu TT, Jiang R, Muliyati NW, Zhang X, Amer MA, Baxter I, Brachi B, Chory J, Dean C, Debieu M, de Meaux J, Ecker JR, Faure N, Kniskern JM, Jones JDG, Michael T, Nemri1 A, Roux F, Salt DE, Tang C, Todesco M, Traw MB, Weigel D, Marjoram P, Borevitz JO, Bergelson J, Nordborg M (2010) Genome-wide association study of 107 phenotypes in Arabidopsis thaliana inbred lines. Nature 465:627-631 https://doi.org/10.1038/nature08800
  3. Bailey LH (1917) Pyrus. Standard cyclopedia of horticulture. Vol. 5. Macmillan, New York
  4. Bao L, Chen K, Zhang D, Cao Y, Yamamoto T, Teng Y (2007) Genetic diversity and similarity of pear (Pyrus L.) cultivars native to East Asia revealed by SSR (simple sequence repeat) markers. Genet Resour Crop Evol 54:959-971 https://doi.org/10.1007/s10722-006-9152-y
  5. Bassil NV, Postman JD, Neou C (2005) Pyrus microsatellite markers from genebank sequences. Acta Hort 671:289-292
  6. Belaj A, Satovic Z, Rallo L, Trujillo I (2002) Genetic diversity and relationships in olive (Olea europaea L.) germplasm collections as determined by randomly amplified polymorphic DNA. Theor Appl Genet 105:638-644 https://doi.org/10.1007/s00122-002-0981-6
  7. Bell RL (1990) Pears (Pyrus), p. 655-697. In: JN Moore, JR Ballington Jr. (eds.). Genetic resources of temperate fruit and nut crops I. ISHS, Wageningen, Netherlands
  8. Buckler ES, Holland JB, Bradbury PJ, Acharya CB, Brown PJ, Browne C, Ersoz E, Flint-Garcia S, Garcia A, Glaubitz JC, Goodman MM, Harjes C, Guill K, Kroon DE, Larsson S, Lepak NK, Li H, Mitchell SE, Pressoir G, Peiffer JA, Rosas MO, Rocheford TR, Romay MC, Romero S, Salvo S, Villeda HS, da Silva HS, Sun Q, Tian F, Upadyayula N, Ware D, Yates H, Yu J, Zhang Z, Kresovich S, McMullen MD (2009) The genetic architecture of maize flowering time. Science 325:714-718 https://doi.org/10.1126/science.1174276
  9. Cockram J, White J, Zuluaga DL, Smith D, Comadran J, Macaulayb M, Luoc Z, Kearseyc MJ, Wernerd P, Harrapd D, Tapselld C, Liub H, Hedleyb PE, Steine N, Schultee D, Steuernagele B, Marshallb DF, Thomasb WTB, Ramsayb L, Mackaya I, Baldingf DJ, The AGOUEB Consortium, Waughb R, O'Sullivana DM (2010) Genomewide association mapping to candidate polymorphism resolution in the unsequenced barley genome. Pro Natl Acad Sci USA 107:21611-21616 https://doi.org/10.1073/pnas.1010179107
  10. Chagne D, Crowhurst RN, Pindo M, Thrimawithana A, Deng C, Ireland H, Fiers M, Dzierzon H, Cestaro A, Fontana P, Bianco L, Lu A, Storey R, Knabel M, Saeed M, Montanari S, Kim YK, Nicolini D, Larger S, Stefani E, Allan AC, Bowen J, Harvey I, Johnston J, Malnoy M, Troggio M, Perchepied L, Sawyer G, Wiedow C, Won K, Viola R, Hellens RP, Brewer L, Bus VGM, Schaffer RJ, Gardiner SE, Velasco R (2014) The draft genome sequence of European pear (Pyrus communis L. 'Bartlett'). PLOS ONE 9:e92644 https://doi.org/10.1371/journal.pone.0092644
  11. Challice JS, Westwood MN (1973) Numerical taxonomic studies of genus Pyrus using both chemical and botanical characters. Bot J Linn Soc 67:121-148 https://doi.org/10.1111/j.1095-8339.1973.tb01734.x
  12. Chun JA, Do KR, Kim SH, Cho KH, Kim HR, Hwang HS, Shin IS (2012) In vitro shoot regeneration from leaf tissue of 'Whangkeumbae' pear (Pyrus pyrifolia Nakai). J Plant Biotechnol 39:288-294 https://doi.org/10.5010/JPB.2012.39.4.288
  13. Dolatowski J, Nowosielski J, Podyma W, Szymanska M, Zych M (2004) Molecular studies on the variability of Polish semi-wild pears (Pyrus) using AFLP. J Fruit Orna Plant Res 12:331-337
  14. Dondini L, Pierantoni L, Gaiotti F, Chiodini R, Tartarini S, Bazzi, Sansavini S (2004) Identifying QTLs for fire-blight resistance via a European pear (Pyrus communis L.) genetic linkage map. Mol Breed 14:407-418 https://doi.org/10.1007/s11032-004-0505-y
  15. Famoso AN, Zhao K, Clark RT, Tung C-W, Wright MH, Bustamante C, Kochian LV, McCouch SR (2011) Genetic architecture of aluminum tolerance in rice (Oryza sativa) determined through genome-wide association analysis and QTL mapping. PLoS Genet 7:e1002221 https://doi.org/10.1371/journal.pgen.1002221
  16. Food and Agriculture Organization of the United Nations (2013) FAOSTAT-Agriculture. Food and Agriculture Organization of the United Nations
  17. Ferree DC, Warrington IJ (2003) Apples: Botany, production and uses. CABI publishing
  18. Gore MA, Chia JM, Elshire RJ, Sun Q, Ersoz ES, Hurwitz BL, Peiffer JA, McMullen MD, Grills GS, Ross-Ibarra J, Ware DH, Buckler ES (2009) A first-generation haplotype map of maize. Science 326:1115-1117 https://doi.org/10.1126/science.1177837
  19. Iketani H, Abe K, Yamamoto T, Kotobuki K, Sato Y, Saito T, Terai O, Matsuta N, Hayashi T (2001) Mapping of disease-related genes in Japanese pear using a molecular linkage map with RAPD markers. Breed Sci 51:179-184 https://doi.org/10.1270/jsbbs.51.179
  20. International HapMap Consortium (2005) A haplotype map of the human genome. Nature 437:1299-1320 https://doi.org/10.1038/nature04226
  21. International HapMap Consortium (2007) A second generation human haplotype map of over 3.1 million SNPs. Nature 449:851-861 https://doi.org/10.1038/nature06258
  22. Iezzoni A, Weebadde C, Luby J, Yue C, van de Weg E, Fazio G, Main D, Peace CP, Bassil NV, McFerson J (2010) RosBREED: Enabling marker-assisted breeding in Rosaceae. Acta Hort 859:389-394
  23. Iezzoni A. Peace CP, Bassil NV, Coe M, Finn C, Gasic K, Luby J, Main D, McFerson, Norelli J, Olmstead M, Whitaker VM, Yue C (2015) RosBREED: Combining disease resistance with horticultural quality in new Rosaceous cultivars. In: Plant and animal genome XXIII conference. PAG
  24. Jang JT, Tanabe K, Tamura F, Banno K (1991) Identification of Pyrus species by peroxidase isozyme phenotypes of flower buds. J Jpn Soc Hortic Sci 60:513-519 https://doi.org/10.2503/jjshs.60.513
  25. Kajiura I, Yamaki S, Omura M, Akihama T, Machida Y (1979) Improvement of sugar content and composition in fruits, and classifications of East Asian pears by the principal component analysis of sugar compositions in fruits (in Japanese with English summary). Jpn J Breed 29:1-12 https://doi.org/10.1270/jsbbs1951.29.1
  26. Kikuchi A (1948) Horticulture of fruit trees. Vol. 1. Yokendo, Tokyo
  27. Kim D, Ko KC (2004) Identification markers and phylogenetic analysis using RAPD in Asian pears (Pyrus spp.). J Kor Soc Hort Sci 45:194-200
  28. Kim HT, Kim HJ, Nou IS, Hirata Y, Kang KK (2002) Identification of self-incompatibility alleles by S-RNases sequencing and PCR-RFLP analysis in Korean-bred pear (Pyrus pyrifolia) strains. Acta Hort 587:467-476
  29. Kim CS, Lee GP, Han DH, Ryu KH, Lee CH (2000) Classification and identification of Pyrus pyrifolia using RAPD. J Kor Soc Hortic Sci 41:119-124
  30. Kimura T, Zhong SY, Moriyuki S, Kazuo K, Nagao M, Tateki H, Yoshiyuki B, Toshiya Y (2002) Identification of Asian pear varieties by SSR analysis. Jpn Breed Sci 52:115-121 https://doi.org/10.1270/jsbbs.52.115
  31. KOSTAT (2014) http://kostat.go.kr/portal/korea/kor_nw/2/7/1/index.board
  32. Kovanda M (1965) On the generic concepts in the Maloideae. Preslia (Praha) 37:27-34
  33. Lamoureux D, Bernole A, Le Clainche I, Tual S, Thareau V, Paillard S, Legeai F, Dossat C, Wincker P, Oswald M, Merdinoglu D, Vignault C, Delrot S, Caboche M, Chalhoub B, Adam-Blondon A-F (2006) Anchoring of a large set of markers onto a BAC library for the development of a draft physical map of the grapevine genome. Theor Appl Genet 113:344-356 https://doi.org/10.1007/s00122-006-0301-7
  34. Laurens F, Aranzana MJ, Arus P, Bonany J, Corelli L, Patocchi A, Peil A, Quilot B, Salvi S, van de Weg E, Vecchietti A (2010) Fruit-Breedomics: A new European initiative to bridge the gap between scientific research and breeding Rosaceae fruit tree crops. Book of abstracts v 2. IHC Lisbon, p. 242
  35. Lin B, Shen D (1983) Studies on the germplasmic characteristics of Pyrus by use of isozymic patterns (in Chinese with English summary). Acta Agr Univ Zhejiang China 9:235-243
  36. Litt M, Luty JA (1989) A hypervariable microsatellite revealed by in vitro amplification of a dinucleotide repeat within the cardiac muscle actin gene. Am J Hum Genet 44:397-401
  37. Luty JA, Guo Z, Willard HF, Ledbetter DH, Ledbetter S, Litt M (1990) Five polymorphic microsatellite VNTRs on the human X chromosome. Am J Hum Genet 46:776-783
  38. Madabhushi RS (1998) Separation of 4-color DNA sequencing extension products in noncovalently coated capillaries using low viscosity polymer solutions. Electrophoresis 19:224-230 https://doi.org/10.1002/elps.1150190215
  39. Maghuly F, Fernandez EB, Ruthner SZ, Pedryc A, Laimer M (2005) Microsatellite variability in apricots (Prunus armeniaca L.) reflects their geographic origin and breeding history. Tree Genet Genomes 1:151-165 https://doi.org/10.1007/s11295-005-0018-9
  40. Mardis ER (2008) The impact of next-generation sequencing technology on genetics. Trends Genet 24:133-141 https://doi.org/10.1016/j.tig.2007.12.007
  41. Mondini L, Noorani A, Pagnotta MA (2009) Assessing plant genetic diversity by molecular tools. Diversity 1:19-35 https://doi.org/10.3390/d1010019
  42. Montanari S, Saeed M, Knabel M, Kim Y, Troggio M, Malnoy M, Velasco R, Fontana P, Won K, Durel C-E, Perchepied L, Schaffer R, Wiedow C, Bus V, Brewer L, Gardiner SE, Crowhurst RN, Chagne D (2013) Identification of Pyrus single nucleotide polymorphisms (SNPs) and evaluation for genetic mapping in European pear and interspecific Pyrus hybrids. PloS ONE 8,e77022 https://doi.org/10.1371/journal.pone.0077022
  43. Monte-Corvo L, Cabrita L, Oliveira C, Leitao J (2000) Assessment of genetic relationships among Pyrus species and cultivars using AFLP and RAPD markers. Genet Resour Crop Evol 47:257-265 https://doi.org/10.1023/A:1008794809807
  44. Moore SS, Sargeant LL, King TJ, Mattick JS, Georges M, Hetzel DJS (1991) The conservation of dinucleotide microsatellites among mammalian genomes allows the use of heterologous PCR primer pairs in closely related species. Genomics 10: 654-660 https://doi.org/10.1016/0888-7543(91)90448-N
  45. Morozova O, Marra MA (2008) Applications of next-generation sequencing technologies in functional genomics. Genomics 92:255-264 https://doi.org/10.1016/j.ygeno.2008.07.001
  46. Nordnorg M, Welgel D (2008) Next-generation in plants. Nature 456:720-723 https://doi.org/10.1038/nature07629
  47. Oh Y, Kim S, Shin H, Won J, Oh S, Kim YK, Kim D (2015a) High-throughput SSR marker development in Korean pear using next-generation sequencing. In: Plant and animal genome XXIII conference. PAG
  48. Oh Y, Kim YK, Kim D (2015b) Current status of knowledge and research perspectives in Korean pear genomics. Plant Breed Biotech 3:323-332 https://doi.org/10.9787/PBB.2015.3.4.323
  49. Okada K, Takasaki T, Saito T, Moriya Y, Castillo C, Norioka S, Nakanishi T (2004) Reconsideration of S-genotype for a Japanese pear 'Kumoi'. J Jpn Soc Hortic Sci 73:524-528 https://doi.org/10.2503/jjshs.73.524
  50. Pierantoni L, Cho KH, Shin IS, Chiodini R, Tartarini S, Dondini L, Kang SJ, Sansavini S (2004) Characterisation and transferability of apple SSRs to two European pear F1 populations. Theor Appl Genet 109:1519-1524 https://doi.org/10.1007/s00122-004-1775-9
  51. Pierantoni L, Dondini L, Cho KH, Shin IS, Gennari F, Chiodini R, Tartarini S, Kang S-J, Sansavini S. (2007) Pear scab resistance QTLs via a European pear (Pyrus communis) linkage map. Tree Genet Genomes 3:311-317 https://doi.org/10.1007/s11295-006-0070-0
  52. Powell W, Machray GC, Provan J (1996) Polymorphism revealed by simple sequence repeats. Trends Plant Sci 1:215-222 https://doi.org/10.1016/S1360-1385(96)86898-0
  53. Prober JM, Trainor GL, Dam RJ, Hobbs FW, Robertson CW, Zagursky RJ, Cocuzza AJ, Jensen MA, Baumeister K (1987) A system for rapid DNA sequencing with fluorescent chain terminating dideoxynucleotides. Science 238:336-341 https://doi.org/10.1126/science.2443975
  54. Rehder A (1915) Synopsis of the Chinese species of Pyrus. Proc Amer Acad Art Sci 50:225-241 https://doi.org/10.2307/20025539
  55. Rubzov GA (1944) Geographical distribution of the genus Pyrus and trends and factors in its evolution. Am Naturalist 78:358-366 https://doi.org/10.1086/281206
  56. Sanger F, Nicklen S, Coulson AR (1977) DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci 74:5463-5467 https://doi.org/10.1073/pnas.74.12.5463
  57. Sax K (1931) The origin and relationships of the Pomoideae. J Arnold Arboretum 12:3-22
  58. Smailus DE, Marziali A, Dextras P, Marra MA, Holt RA (2005) Simple, robust methods for high-throughput nanoliter-scale DNA sequencing. Genome Res 15:1447-1450 https://doi.org/10.1101/gr.4221805
  59. Smith LM, Sanders JZ, Kaiser RJ, Hughes P, Dodd C, Connell CR, Heiner C, Kent SBH, Hood LE. (1986) Fluorescence detection in automated DNA sequence analysis. Nature 321:674-679 https://doi.org/10.1038/321674a0
  60. Sun W, Zhang Y, Le W (2009) Construction of a genetic linkage map and QTL analysis for some leaf traits in pear (Pyrus L.). Front Agric China 3:67-74
  61. Tan XF, Wuyun T, Zhang DQ, Zeng TL, Li XG (2008) Isolation and identification of seven new S-RNase genes from Pyrus pyrifolia in China. Acta Hort 769:289-296
  62. Teng Y, Tanabe K, Tamura F, Itai A (2001) Genetic relationships of pear cultivars in Xinjiang, China as measured by RAPD markers. J Hortic Sci Biotech 76:771-779 https://doi.org/10.1080/14620316.2001.11511444
  63. Teng Y, Tanabe K, Tamura F, Itai A (2002) Genetic relationships of Pyrus species and cultivars native to East Asia revealed by randomly amplified polymorphic DNA markers. J Am Soc Hortic Sci 127:262-270
  64. Terakami S, Nishitani C, Kunihisa M, Shirasawa K, Sato S, Tabata S, Kurita K, Kanamori H, Katayose Y, Takada N, Saito T, Yamamoto T (2014) Transcriptome-based single nucleotide polymorphism markers for genome mapping in Japanese pear (Pyrus pyrifolia Nakai). Tree Genet Genomes 10:853-863 https://doi.org/10.1007/s11295-014-0726-0
  65. Varshney RK, Nayak SN, May GD, Jackson SA (2009) Nextgeneration sequencing technologies and their implications for crop genetics and breeding. Trends Biotechnol 27:522-530 https://doi.org/10.1016/j.tibtech.2009.05.006
  66. Weber JL, May PE (1989) Abundant class of human DNA polymorphisms which can be typed using the polymerase chain reaction. Am J Hum Genet 44:388-396
  67. Westwood MN, Challice JS (1978) Morphology and surface topography of pollen and anthers of Pyrus species. J Amer Soc Hort Sci 103:28-37
  68. Winter P, Kahl G (1995) Molecular marker technologies for plant improvement. World J Microbiol Biotechnol 11:438-448 https://doi.org/10.1007/BF00364619
  69. Won J, Oh Y, Kim S, Shin H, Oh S, Kim YK, Kim D (2015) Development of high-throughput Indel marker based on next generation sequencing in Korean pears (Pyrus spp.). In: Plant and animal genome XXIII conference. PAG
  70. Wu J, Li L-T, Li M, Khan MA, Li X-G, Chen H, Yin H, Zhang S-L (2014) High-density genetic linkage map construction and identification of fruit-related QTLs in pear using SNP and SSR markers. J Exp Bot doi: 10.1093/jxb/eru311
  71. Wu J, Wang Z, Shi Z, Zhang S, Ming R, Zhu S, Khan MA, Tao S, Korban SS, Wang H, Chen NJ, Nishio T, Xu X, Cong L, Qi1 K, Huang X, Wang Y, Zhao X, Wu J, Deng C, Gou C, Zhou W, Yin H, Qin G, Sha Y, Tao Y, Chen H, Yang Y, Song Y, Zhan D, Wang J, Li L, Dai M, Gu C, Wang Y, Shi D, Wang X, Zhang H, Zeng L, Zheng D, Wang C, Chen M, Wang G, Xie L, Sovero V, Sha S, Huang W, Zhang S, Zhang M, Sun J, Xu L, Li Y, Liu X, Li O, Shen J, Wang J, Paull RE, Bennetzen JL, Wang J, Zhang S (2013) The genome of the pear (Pyrus bretschneideri Rehd.). Genome Res 23:396-408 https://doi.org/10.1101/gr.144311.112
  72. Yakovin NA, Fesenko IA, Isachkin AV, Karlov GI (2011) Polymorphism of microsatellite loci in cultivars and species of pear (Pyrus L.). Rus J Genet 47:564-570 https://doi.org/10.1134/S1022795411040156
  73. Yamamoto T, Kimura T, Shoda M, Imai T, Saito T, Sawamura Y, Kotobuki K, Hayashi T, Matsuta N. (2002) Genetic linkage maps constructed by using an interspecific cross between Japanese and European pears. Theor Appl Genet 106:9-18 https://doi.org/10.1007/s00122-002-0966-5
  74. Yamamoto T, Kimura T, Terakami S, Nishitani C, Sawamura Y, Saito T, Kotobuki K, Hayashi T (2007) Integrated reference genetic linkage maps of pear based on SSRs and AFLPs. Breed Sci 57:321-329 https://doi.org/10.1270/jsbbs.57.321
  75. Yamamoto T, Chevreau E (2009) Pear genomics, p. 163-186. In: Genetics and genomics of Rosaceae. Springer, New York
  76. Yamamoto T, Terakami S, Moriya S, Hosaka F, Kurita K, Kanamori H, Katayose Y, Saito T, Nishitani C (2011) DNA markers developed from genome sequencing analysis in Japanese pear (Pyrus pyrifolia). In: XIII Eucarpia symposium on fruit breeding and genetics 976:477-483
  77. Yamamoto T, Terakami S, Takada N, Nishio S, Onoue N, Nishitani C, Kunihisa M, Inoue E, Iwata H, Hayashi T, Itai A, Saito T (2014) Identification of QTLs controlling harvest time and fruit skin color in Japanese pear (Pyrus pyrifolia Nakai). Breed Sci 64:351-361 https://doi.org/10.1270/jsbbs.64.351
  78. Yuan F, Du S (1980) Pears of northwestern China (in Chinese). Shaanxi Sci Technol Press, Xian, People's Republic of China
  79. Zhang R-P, Wu J, Li X-G, Khan MA, Chen H, Korban SS, Zhang S-L (2013) An AFLP, SRAP, and SSR genetic linkage map and identification of QTLs for fruit traits in pear (Pyrus L.). Plant Mol Biol Rep 31:678-687 https://doi.org/10.1007/s11105-012-0544-1
  80. Zeven AC, Zhukovsky M (1975) Dictionary of cultivated plants and their centres of diversity. Centre for Agricultural Publishing and Documentation. Wageningen
  81. Zou L, Zhang X, Zhang Z, Sun B, Guo S (1986) Studies on the systematic relationship of some of the species in the genus Pyrus based on pollen grain morphology (in Chinese with English summary). Acta Hort Sinica 13:219-224