Heading Uniformity: A New Comprehensive Indicator of Rice Population Quality

Abstract

Productive tiller percentage (PTP) is the only available comprehensive indicator of rice population quality. However, productive panicle number (PN) has a great effect on its characterization accuracy. Panicle exsertion is an important but difficult to describe morphological index; therefore, it cannot be easily determined. The aims of this study were to develop heading uniformity (HU), which describes the difference in the degree of rice panicle exsertion, as a new comprehensive indicator by designing a representative sampling and calculation method and exploring the relationship between HU and yield components. HU first decreased then increased after initial heading, exhibiting a single-valley curve. Adequate HU was obtained by panicle sampling on day two or three (panicle N fertilizer proportion ≤40 or >40%) after initial heading. The explanatory power of PTP for grain yield variance was markedly insufficient in low- and high-PN rice populations. Compared with the percent contribution of PTP to grain yield variance (12.32–41.26%), that of HU (49.02–61.93%) was greater and more stable across rice populations of different PNs. Moreover, HU showed fewer interannual variations, despite large interannual differences in weather and soil conditions. Hence, HU may have applications as a comprehensive indicator of rice population quality.

Reduced Nitrogen Input Combined with Nitrogen-Saving japonica Rice Varieties Balances Yield and Nitrogen Use Efficiency in The Lower Reaches of the Yangtze River in China

“…High productive tiller percentage (PTP) is a healthy index for population quality [31,32], and rice grain yield is associated with tillering capacity and panicle number under low-N input [22,33]. Our results corroborated these findings, where high PTP was achieved under a reduced N level for the NSVs and GVs, and the grain yield was in an acceptable range for the NSVs.…”

Uniformity test of the upland rice lines F8 from crosses of local Bangka rice and lodging resistance superior varieties in Belitung Regency

“…[16] stated that homogeneity in the observations made showed that the population has been uniform. According to [17], if the character of the tested line shows uniformity, it can be assumed that the character in the line is stable. Note : "Genotypic variability" σ²g ≥ 2 (σ σ²g) = wide, σ²g < 2 (σ σ²g) = narrow; "Phenotypic variability" σ²f ≥ 2 (σ σ²f) = wide, σ²f < 2 (σ σ²f) = narrow.…”

Effects of postponing nitrogen topdressing on starch structural properties of superior and inferior grains in hybrid indica rice cultivars with different taste values

“…The experiment employed a two-factor, completely randomized design, incorporating diverse strategies for managing N fertilizer and different varieties. Based on a stable and efficient reduction of nitrogen application rate of 150 kg N hm -2 ( Sun et al., 2023 ), three N management practices were established: zero N (denoted as N 0 ), local farmer practice (basal N fertilizer: tillering N fertilizer: panicle N fertilizer=7:3:0, denoted as N 1 ) ( Shu et al., 2021 ; Shu et al., 2022 ), postponing N topdressing (basal N fertilizer: tillering N fertilizer: panicle N fertilizer=3:1:6, denoted as N 2 ). The N fertilizer (urea) was managed as follows: The base fertilizer was applied 1 d before transplanting, the tillering fertilizer was applied 7 d after transplanting, and the panicle fertilizer was applied at a 1:1 ratio during the inverse fourth-leaf and second-leaf stages.…”