Response of differentiated and degenerated spikelets to top-dressing, shading and day/night temperature treatments in rice cultivars with large panicles

Responses of Yielding Ability, Sink Size and Percentage of Filled Grains to the Cultivation Practices in a Chinese Large-Panicle-Type Rice Cultivar, Yangdao 4

“…Analysis of the effects of cultivation practices on the yielding ability in relation to sink size and PFG might reveal practical information on high-yielding cultivation of these large-panicle-type cultivars. Therefore, we carried out field experiments using a Chinese large-panicle-type cultivar, whose yielding ability was analyzed previously (Yao et al, 2000a(Yao et al, , 2000bYamamoto et al, 2001;Ansari et al, 2003;Ju et al, 2006). The aim was to clarify the effects of cultivation practices, such as planting density, number of seedlings hill -1 and method of fertilizer application (supplement application of fertilizer to deep layer), on the NP-m 2 and NS-P, on the sink size and PFG, which determine the yielding ability.…”

Relationship between Dry Weight at Heading and the Number ofSpikelets on Individual Rice Tillers

“…The correlation coefficients between SP and DWP were higher than those between SP and amount of nitrogen per panicle (Yao et al, 2000b). In data of Yao et al (2000b), we found that shading decreased SP compared to regression of SP on the amount of nitrogen per panicle, but did not affect the relationship between SP and DWP, which also suggests that dry matter production is more essential to spikelet production than the amount of nitrogen. The fact that SP is reduced by shading (Matsushima, 1957;Yao et al, 2000b) supports our conclusion because shading decreases dry weight, but not the amount of nitrogen, per hill (Kobayasi et al, 2001c).…”

“…In data of Yao et al (2000b), we found that shading decreased SP compared to regression of SP on the amount of nitrogen per panicle, but did not affect the relationship between SP and DWP, which also suggests that dry matter production is more essential to spikelet production than the amount of nitrogen. The fact that SP is reduced by shading (Matsushima, 1957;Yao et al, 2000b) supports our conclusion because shading decreases dry weight, but not the amount of nitrogen, per hill (Kobayasi et al, 2001c). Dry matter production per panicle is related to SP (Kobata and Notsu, 1991;Yao et al, 2000a), but the relationship between DWT and ST has not been reported.…”

“…However, these authors focused on S, rather than ST and SP, and S is a product of SP and P, which can also be affected by nitrogen. Furthermore, in our study, the nitrogen concentration of each tiller at heading was not correlated with ST. SP is positively correlated with DWP (Yao et al, 2000b) and the mean amount of nitrogen per panicle at heading (Wada, 1969;Yao et al, 2000b). The correlation coefficients between SP and DWP were higher than those between SP and amount of nitrogen per panicle (Yao et al, 2000b).…”

“…Furthermore, in our study, the nitrogen concentration of each tiller at heading was not correlated with ST. SP is positively correlated with DWP (Yao et al, 2000b) and the mean amount of nitrogen per panicle at heading (Wada, 1969;Yao et al, 2000b). The correlation coefficients between SP and DWP were higher than those between SP and amount of nitrogen per panicle (Yao et al, 2000b). In data of Yao et al (2000b), we found that shading decreased SP compared to regression of SP on the amount of nitrogen per panicle, but did not affect the relationship between SP and DWP, which also suggests that dry matter production is more essential to spikelet production than the amount of nitrogen.…”