青枯病抵抗性トマト安濃9号の育成とその特性

摘要

1）生食用大玉，育枯病抵抗性の‘とまと中間母本農9号，と青枯病抵抗性のフィリピン在来品種‘R-3034-3-10-N-UG，とを交雑し，草勢や育枯病抵抗性をもとに自殖と選抜を繰り返し，国定系統トマト安濃9号を育成した．トマト安濃9号は‘とまと中間母本農9号’および‘LS89，に比べ，高度の青枯病抵抗性を示す．　2）トマト安濃9号は，高温期に一部心止まり性を示すものの，通常は非心止まり性で，その完熟果色は桃色である．一束重は約80gで，‘桃太郎8’や‘とまと中間母本農9号，に比べ小さい．果実の硬さは‘桃太郎8’と同等であり，‘とまと中間母本農9号’より硬い．糖度（Brix）は‘とまと中間母本農9号’や‘桃太郎8’より低い．3）トマト安濃9号と青枯病権柄性‘とまと中間母本農5号，との交雑F_1世代およびF_2世代の抵抗性指数は幅広く分布し，その平均値は両親の抵抗性指数の中間値付近であったことから，トマト安濃9号の有する育枯病抵抗性は，複数の遺伝子に支配され，総体的には不完全優性に遺伝するものと推定される．また，F_2世代の一果垂と抵抗性指数との間に密接な相関は認められず，本育成系統は育枯病抵抗性を有する生食用桃色完熟果の中～大玉トマトの育種素材として有用であると判断される．4）トマト安濃9号の種子は，「独立行政法人農業・食品産業技術総合研究機構における育成系統取扱規則」に従った分譲が可能である．%To produce a tomato line with a high level of bacterial wilt resistance, we performed an intraspecific cross between the Philippine cultivar 'R - 3034 - 3 - 10 - N -UG' and the Japanese cultivar 'Tomato Chuukanbohon Nou 9 Go'. After continuous self ing and selection for bacterial wilt resistance and plant vigor, we selected a highly resistant line from the F_6 progeny and named this line Tomato Ano 9 Go. The resistance of the line was higher than those of 'Tomato Chuukanbohon Nou 9 Go' and 'LS89'.rnTomato Ano 9 Go is of the conditional indeterminate type, and its fruit is a slightly flattened round shape, with a pink outer color. Its fruit weight is approximately 80 g, which is lighter than those of 'Momotaro 8' and 'Tomato Chuukanbohon Nou 9 Go'. The fruit's soluble solids (°Brix) content is lower than those of 'Tomato Chuukanbohon Nou 9 Go' and 'Momotaro 8'.rnSince the average bacterial wilt resistance index in the F_2 population derived from crossing Tomato Ano 9 Go and 'Tomato Chuukanbohon Nou 5 Go', a susceptible cultivar, is close to the median value of the two parents and ranged from susceptible to resistant, the resistance to bacterial wilt in Tomato Ano 9 Go appears to be controlled by multiple genes with incomplete dominance. Since there was no significant correlation between fruit weight and the resistance index in the F_2 population, Tomato Ano 9 Go is a highly promising material for breeding fresh - market varieties with bacterial wilt resistance.rnSeeds of Tomato Ano 9 Go are available upon request from the authors under a materials transfer agreement.