The Tiller maximum cv. Natsukaze) and green panic (P. maximum Jacq. var. trichoglume Eyles).

Abstract

The mechanisms responsible for the difference in the post heading dry matter production between guineagrass (GN) and green panic (GG) was analyzed in terms of the number, weight and development of heading tillers. The plant dry weight increased in both GN and GG with time after heading, showing a greater rate of increase in GN than in GG. The tiller number per plant also increased in both grasses, mainly owing to the increase in the number of higher nodal-position tillers (HP) which had lower tiller weights than lower-nodal-position tillers. The number of HP was greater in GG than in GN. The expanded leaf number before flag leaf formation of the heading tiller decreased in both grasses as the heading stage progressed, with a greater rate of decline in GG than in GN. Because the weight of individual heading tillers decreased as the total leaf expansion decreased, GG, which showed a larger decline in the expanded leaf number before flag leaf formation, produced more heading tillers of smaller weight with time after heading. Thus, it was shown that the developmental dynamics of the heading tillers was an important factor characterizing the post-heading dry matter production in the two grasses.