難裂莢性を導入した大豆新品種「フクユタカA1 号」の育成

「フクユタカA1 号」は、「フクユタカ」の裂莢性改善を目標として、DNA マーカーによる難裂莢遺伝子導入個体の選抜と「フクユタカ」への5 回の戻し交配を組み合わせて育成した品種である。 裂莢性以外の成熟期、耐倒伏性、タンパク質含量などの主要な形質は「フクユタカ」とほぼ同等である。難裂莢性を備えているため、刈り遅れ時の自然裂莢が少なく、コンバイン収穫時の実質的な収量増が期待できることから、2014 年に「フクユタカA1号」と命名し、品種登録出願を行った。The yield of soybean production in Japan is significantly lower than the world average. Two of the causes are natural pod dehiscence and loss during combine harvesting.Of the land in Japan cultivated with soybean, “Fukuyutaka” occupies the largest area, and this cultivar is especially widely grown in the southwest of the country. Since its release in 1980, it has shown a high yield potential and good suitability for tofu processing; therefore, it is in high demand.However, “Fukuyutaka” is susceptible to pod dehiscence at maturity, and losses occur through a combination of a high level of natural pod dehiscence and combine harvesting. Our aim was to improve “Fukuyutaka,” and we developed “Fukuyutaka A1 gou” by DNA marker assisted selection using markers related to pod dehiscence (pdh1) and backcrossing five times with “Fukuyutaka.”Except for pod dehiscence susceptibility, other major agronomic traits of “Fukuyutaka A1 gou,” such as flowering time, maturation time, lodging resistance, unit yield, and protein content, are almost the same as “Fukuyutaka.” Further, the suitability for tofu processing is similar to that of “Fukuyutaka.” In field trials, the total yield of “Fukuyutaka A1 gou,” including harvesting losses, was equivalent to that of “Fukuyutaka,” but the yield from combine harvesting was clearly higher than “Fukuyutaka.” For this reason, by replacing “Fukuyutaka” with “Fukuyutaka A1 gou,” it is expected that the soybean yield in southwest Japan would be improved for the benefit of farmers, and we have applied for cultivar registration as “Fukuyutaka A1 gou.