title: Seed formation in triploid loquat (Eriobotrya japonica) through cross-hybridization with pollen of diploid cultivars.
abstract: As the fruits of loquat (Eriobotrya japonica, 2n = 2x = 34) carry large seeds, the breeding of seedless loquat has long been a goal. The recent creation of triploid cultivars (2n = 3x = 51) and the application of gibberellins allow commercial production of seedless loquat, but the possibility of seed formation in triploid loquats has not been carefully investigated. Through crossing experiments and cytological observations of meiosis and pollen tube growth, we found that the triploid line 3N-N28 was essentially self-sterile, but developed seeds on pollination with pollen from diploid cultivars at rates of up to 5.5%. Almost half of the seedlings survived to 5 months, and carried diploid (2n = 34), tetraploid (2n = 68), or aneuploid chromosome numbers. Our results suggest that triploid loquat cultivars might retain the risk of seed formation. Protection from pollination by diploid cultivars or the development of new triploid cultivars will be necessary to ensure the production of seedless loquat fruits.
authors.affiliation: Graduate School of Horticulture, Chiba University , Matsudo 648, Matsudo, Chiba 271-8510 , Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kikuchi
authors.affiliation: Faculty of Horticulture, Chiba University , Matsudo 648, Matsudo, Chiba 271-8510 , Japan.
authors.forename: Miwako
authors.initials: M
authors.lastname: Iwasuna
authors.affiliation: Faculty of Horticulture, Chiba University , Matsudo 648, Matsudo, Chiba 271-8510 , Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Kobori
authors.affiliation: Southern Prefectural Horticulture Institute, Chiba Prefectural Agriculture and Forestry Research Center , Yamamoto 1762, Tateyama, Chiba 294-0014 , Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Tsutaki
authors.affiliation: Awa Agriculture Office , Hojyo 402-1, Tateyama, Chiba 294-0045 , Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshida
authors.affiliation: Chiba Prefectural Agriculture and Forestry Research Center , Daizen-no 808, Midori, Chiba, Chiba 266-0006 , Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Murota
authors.affiliation: Graduate School of Horticulture, Chiba University , Matsudo 648, Matsudo, Chiba 271-8510 , Japan.
authors.forename: Eisho
authors.initials: E
authors.lastname: Nishino
authors.affiliation: Graduate School of Horticulture, Chiba University , Matsudo 648, Matsudo, Chiba 271-8510 , Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Sassa
authors.affiliation: Graduate School of Horticulture, Chiba University , Matsudo 648, Matsudo, Chiba 271-8510 , Japan.
authors.forename: Takato
authors.initials: T
authors.lastname: Koba
keywords: cross-hybridization; loquat; meiosis; pollen tube growth; seed formation; triploid