Diversity of Stay Green Traits in Flag Leaf of Rice

[摘要] Cultivar variances in the stay green trait of flag leaves in NIAS World (WRC), Japanese (JRC) rice core collection and Chinese high yielding hybrid and inbred cultivars were investigated. A leaf color reading (SPAD) was determined using the chlorophyll meter at the center of the flag leaf segment floated on water at 35°C under dark conditions for one week. There was a large cultivar variance in a ratio of after (SPAD E ) to before (SPAD S ) incubation in SPAD (GM= SPAD E /SPAD S ). In WRC and JRC cultivars, GM in japonica rice tended to occupy a higher rate than indica and tropical japonica rice. There were typical cultivars of high GM in which both SPAD E and SPAD S were significantly high. In Chinese high yielding rice (9–11 t ha -1 ), the GM diversely differed and positively related with harvest index and the grain yield per total straw weight × SPAD value. These relationships suggested that higher GM increased the productivity of straw for the grain yield due to maintenance of chlorophyll function. It was suggested that the stay green trait is widely distributed in rice resources and it can be used for the improvement of rice production.

[关键词] Flag leaf;Indica;Japanese rice core collection;Japonica;Rice;Stay green;World rice core collection.