リンゴ3品種の自家結実性および後代実生のS遺伝子型判別(育種・遺伝資源)  [in Japanese] Self-compatibility of 3 Apple Cultivars and Identification of S-allele Genotypes in Their Self-pollinated Progenies(Breeding & Germplasm Resource)  [in Japanese]

本試験では1998年〜2001年にわたり,自家結実率の高さに違いのある3品種を用いて自家受粉試験を行った.'ふじ'では花粉にX線を急照射した花粉を自家受粉する試験区も設けた.自家受粉による結実数の調査をした結果,'ふじ'の自家受粉試験区では,全般的に結実数は少ない傾向であり,4年間の結実率は0〜4.5%であった.'王林'および'恵'の自家受粉試験区ではそれぞれ,16〜35果と20〜24果と結実果が多く得られ,それぞれ結実率も16.3〜38%,40%と高かった.また,X線照射花粉の自家受粉でも結実率の向上は認められなかった.結実果の種子数を調査した結果,それぞれ差が認められ'ふじ'は'恵'よりも少なく,'王林'の結実果のほとんどは種子の無いものが多かった.'王林'の受粉,無受粉試験を行った結果,いずれの試験区でも高い結実率を示したが,内蔵する種子はすべて退化していた.この様に'王林'の自家結実率の高さは自動的単為結果性の高さに加えて,受粉の刺激によりさらに単為結実率が高くなったことが明らかになった.なお,受粉試験で得られた結実果から種子を取り出して,胚培養を行い多数の後代実生を得,これらのS遺伝子に特異的DNAマーカーによりS遺伝子型の判定を行い,自家受粉由来個体と他家受粉由来個体を識別した.これらの後代実生は温室で育成しているが,なかには生育異常を示す個体も認められた.

We analyzed fruit and seed sets after self-pollination in 3 apple cultivars. Between 1998 and 2001, we carried out self-pollination of cultivars 'Megumi', 'Orin' and 'Fuji', which exhibit different levels of self-incompatibility. In addition, we carried out self-pollination of 'Fuji' using X-ray irradiated pollen. Self-pollination of 'Fuji' showed percentages of fruit sets ranging from 0 to 4.5% over 4 years. In contrast, self-pollination of 'Megumi' and 'Orin' showed higher percentages ranging from 40 to 48% in the 2^<nd> year and from 16.3 to 38% in the 3^<rd> year. There were no differences in fruit set between experiments using X-ray irradiated pollen and non-irradiated pollen. 'Megumi' showed the production of seeded fruits, however, most of 'Orin' resulted in the production of fruits without seeds. We carried out self- and non-pollination of 'Orin', resulting in a high percentage of fruit set on average in all cases. All trees showed fruit but no seed. These results demonstrated that 'Orin' possess autonomic and/or stimulative parthenocarpy. From self-pollination of 'Fuji', we obtained many progenies from fruits containing seeds by the application of embryo culture, however, the percentages of seed set in 'Fuji' were less than those in 'Megumi'. PCR amplification using S-allele-specific primers showed the possibility that some progeny were derived from self-compatible fertilization. These self-pollinated plants were grown in green house, however, some plants showed abnormal phenotypic appearances.