台灣桑樹之分類及品種改良

Taxonomy and Cultivar Improvement of Mulberry in Taiwan

台灣桑樹依其枝條、葉片、花柱、花穗、果實形態與休眠習性可分為七大系統，分別為魯桑（M. latifolia）、廣東桑（M. atropurpurea）、長果桑（M. laevigata）、白桑（M. alba）、山桑（M. bombycis）、島桑（M. australis）與台灣桑（M formosnensis）等。早年蠶業改良場（農委會苗栗區農業改良場之前身）曾於1920-1978年間育成台桑1號（M. acidosa）、‘台桑2號’（M. alba）及‘台桑3號’（M. alba）等3種週年常綠之葉用品種（葉桑）供飼蠶之用。惟民國80年以後因蠶業式微，葉桑產業隨之沒落；但隨後在台灣省政府「果樹少量多樣化」的政策之下，桑果（桑椹）漸受歡迎。苗栗場乃陸續自種源區中篩選出若干具有生長快速、適應性強、豐產、大果或果實品質優良之果用品系（果桑），如'46C019'（M. atropurpurea）（多果桑）、'70C006'（M. laevigata）（長果桑）、'72C002'（M. atropurpurea）（多果桑）及'93C203'（M. atropurpurea）（多果桑）等4種；另亦選出樹型優雅，可作為觀賞植物之'74C005'（M. latifolia）（雲龍桑）及'69C002'（M. alba）（垂枝桑）等2種。迭經多年的栽培、引種、選拔、育種及演化，桑樹已成為台灣重要之特用、保健與園藝作物。鑑於過去桑樹形態分類之不足與國內仍無果桑命名品種，本場仍將持續桑樹分類（如台桑2、3號似不應屬白桑系）與育種之研究，未來應以分子標誌進行桑樹親緣性分析、篩選高總抗氧化能力及高機能性成份之品系以及進行高糖度、耐（抗）菌核病（swollen fruit disease）品種之選育，俾申請品種權，以利產業之發展。 According to the characteristics of morphology such as shoot, leaf, stigma, fruit, and tree dormancy habit, mulberry (Morus spp.) populations in Taiwan can be categorized into seven groups: M. latifolia; M. atropurpurea; M. laevigata; M. alba; M. bombycis; M. australis; and M. formosnensis. The Miaoli District Agricultural Research and Extension Station (MDARES) (formerly the Taiwan Sericultural Improvement Station) released three foliage cultivars named 'Taisang No.1' (M. acidosa), 'Taisang No. 2 (M. alba), and 'Taisang No. 3 (Morus alba) to feed silkworm for silkworm production during 1920-1978 period. Since the 1990s, because of the fruit's multiple uses, i.e., as a table fruit, as an agritourist attraction, as a raw material for juice, jam and winemaking, and due to the high antioxidant, the demand for mulberry has increased markedly. Mulberry has since become a popular fruit and herbal crop in Taiwan. Four promising fruiting mulberry genotypes '46C019' (M. atropurpurea), '70C006' (M. laevigata), '72C002' (M. atropurpurea), and '93C203' (M. atropurpurea) and two elite ornamental genotypes, '74C005' (M. latifolia) and '69C002' (Morus alba), were recently selected by MDARES for their abundant yield, strong adaptability, superior quality or landscape uses. Further studies related to identification of the mulberry relationship using molecular markers, to distinguishing the genotypes with high antioxidant and high levels of responsible phytochemicals, and to selection of the fruiting genotypes with high total soluble solids, offseason production potential, and resistance to swollen disease (Ciboria shiraiana) will be required to promote development in the mulberry industry.