サトウキビとエリアンサスとの属間交雑における DNA マーカーを用いた雑種判定法の検証

The sugarcane Breeding Unit in the National Agricultural Research Center for Kyushu Okinawa Region has been working on intergeneric hybridization between sugarcane (Saccharum spp. hybrid) and Erianthus (Erianthus arundinaceus) to develop innovative breeding materials. In the present study, we applied Erianthus-specific EaCIR1 and 5S rDNA markers to identify hybrids. EaCIR1 is a tandemly-repeated DNA sequence in the subtelomeric regions of most Erianthus chromosomes. Progenies produced by intergeneric crossing (sugarcane x Erianthus) were divided into three groups : group A had both EaCIR1 and 5S rDNA markers, group B had only the EaCIR1 marker, and the other group did not have either marker. Seedlings of group A exhibited poor growth and had intermediate DNA amounts between their parents. One of them lost dewlaps (joint part of leaf blade and sheath) as morphologically similar to Erianthus. These results indicated that group A was composed of intergeneric hybrids. Group B had dewlaps and growth characteristics similar to sugarcane instead of Erianthus. The amount of DNA in seedlings of group B was almost the same as that of their maternal sugarcane. Marker analyses with 28 Erianthus-specific primers revealed no Erianthus-specific band pattern in group B. These results did not present any evidence that Erianthus chromosomes were introduced into individuals of group B. Consequently, the EaCIR1 marker should not be Erianthus-specific. Additionally, we used marker analyses to investigate a large number of progenies produced by intergeneric crossing, and did not find any individuals that contained Erianthus chromosomes. This suggested that partial introduction of Erianthus chromosomes into progeny by intergeneric crossing was less likely.九州沖縄農業研究センターさとうきび育種ユニットは, サトウキビとエリアンサスの属間雑種作出に取り組んできた。5SrDNA マーカーによる雑種判定法は既に確立しているが, 本報では, 属間交雑後代にエリアンサス染色体の一部のみが導入される場合も想定し, より広汎な染色体を検出可能な EaCIR1 マーカーを併用して雑種判定を行った。その結果, 両マーカーが検出される個体群と EaCIR1 マーカーのみが検出される個体群が認められた。前者では肥厚帯消失や生育の弱勢化が認められ, DNA 量も両親の中間値を示し, 明らかに属間雑種であると考えられた。後者では肥厚帯消失は認められず, 生育特性は母本のサトウキビに近い個体が多く, DNA 量もサトウキビ経済品種と同程度であった。また, 28種のエリアンサス由来プライマーを用いたマーカー解析でも, 後者ではエリアンサスに特異的なバンドは検出されなかった。以上から, EaCIR1 マーカーは必ずしもエリアンサス属だけに特異的ではないことが示唆された。また, マーカー解析には属間交雑を試みた多数の後代個体を供試したが, 一部のプライマーのみでバンドが検出されるような, 染色体の部分的導入を示す結果が得られた個体はなかった。このことから, 染色体の部分的な導入が生じる可能性は低いか, 少なくとも育種上問題となる頻度で生じる現象ではないと考えられた

山形県におけるアカスモモ及び在来ナシの探索・収集

Exploration for collecting local varieties of plum and pear was conducted in Yamagata Prefecture on July 3 to 5 and November 8 to 11, 2005. \u27Akasumomo\u27 widely distributed in Yamagata Prefecture as garden tree, and are thought to be hybrids between Prunus cerasifera and P. salicina based on the characteristics of trees and fruit. We collected 11 clones, and these clones are useful to clarify the history of the introduction and the utilization of P. cersifera in Japan. A total of 18 local varieties of pear which are planted mainly in a garden of a farmhouse were collected. Most of the local varieties surveyed in Oishida Town (Jinengo) are thought to be Pyrus ussuriensis var. ussuriensis or its hybrid based on the characteristics of trees and fruit. Branch, leaf and fruit samples were collected for each accession. The collected materials will be conserved by grafting and assessed for the agronomic characters