Differences in growth and grain yield performance between old and new winter wheat varieties Hokushin and Kitahonami in Hokkaido
2016
Kasajima, S. (Tokyo Univ. of Agric., Abashiri (Japan). Fac. of Bioindustry) | Imai, K. | Shimizu, T. | Itoh, H. | Nakamaru, Y. | Yoshida, H. | Sato, M. | Jinno, H. | Yoshimura, Y. | Takahashi, T.
In Hokkaido, a leading winter wheat variety, Kitahonami, shows higher yielding ability than a previous variety, Hokushin. To identify the factors determining the high-yielding ability of Kitahonami, we compared its growth and grain yield performance with those of Hokushin in two growing seasons (2011-12 and 2012-13). The grain yield of Kitahonami was 8% greater than that of Hokushin. This difference was due to a higher number of grains per ear and 1000-grain weight. The high-yielding ability of Kitahonami was attributed to the large sink capacity. At maturity, the total dry weight of Kitahonami was 13% heavier than that of Hokushin. This increased total dry weight was a result of the increased crop growth rate (CGR) from the milk-ripe to maturity stage. In particular, the dry weight of the ear was greatly increased. A strong source activity during the later grain filling phase also contributed to the high-yielding ability of Kitahonami. The nitrogen content of the second and third leaves at the milk-ripe and maturity stages was higher in Kitahonami than in Hokushin. The erect green leaves of Kitahonami probably absorbed radiation more effectively than those of Hokushin, leading to a higher net assimilation rate (NAR) in the later grain filling phase and higher dry-matter production after the milk-ripe stage.
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