使用限制酶位點標定之核酸定序法進行稉稻雜交組合之穗上發芽數量性狀基因座的遺傳定位

Abstract

穗上發芽（pre-harvest sprouting）是指生理成熟的穎果在收穫前發芽，而造成產量損耗與稻米品質下降。本試驗選用高穗上發芽率品種「臺稉14號」以及低穗上發芽率品種「桃園1號」，建立水稻F2遺傳定位族群並進行穗上發芽與種子休眠之數量性狀基因座（quantitative trait locus; QTL）分析。首先在F2族群中挑選出穗上發芽率最高與最低的個體共60株，並萃取這些植株的核酸來進行限制酶位點標定（restriction-site associated DNA; RAD）之核酸定序，以便同時開發足夠數目的SNP分子標記並完成選拔個體之所有分子標記的基因型鑑定。亦由此60個F2個體繁殖成F2:3家系，進一步觀察穗上發芽與種子休眠維持日數之關聯性。試驗結果顯示，穗上發芽與種子休眠性之數量性狀基因座被定位在第3對染色體上相同的染色體區間。 Preharvest sprouting refers to ripe kernels germinate before harvest, which leads to yield loss and poor grain quality. A rice F2 genetic mapping population was created by the cross of TK14, a variety with high preharvest sprouting rate, and TY1, a variety with low preharvest sprouting rate, and then conducted QTL analysis for preharvest sprouting and seed dormancy. A total of 60 individuals with highest and lowest preharvest sprouting rate in the F2 population were selected, and their DNA were extracted to do RAD (restriction-site associated DNA) sequencing, in order to develop sufficient number of SNP markers as well as to identify these SNP marker genotypes of the selected individuals simultaneously. F2:3 families from the selected F2 individuals were also generated and the relationship between preharvest sprouting and seed dormancy was investigated. The results showed that QTLs for both preharvest sprouting and seed dormancy were detected on the same region of chromosome 3.