高产与优良食味是杂交籼稻生产的两个重要目标，其协同难度较大。本研究根据稻谷产量和米饭食味值筛选出高产优良食味（HYGT）、低产优良食味（LYGT）和高产普通食味（HYPT）等3种类型杂交籼稻品种，深入研究了3种类型品种的物质生产特性、产量构成特征及稻米食味品质。结果表明，同为优良食味类型，高产优良食味品种较低产优良食味品种产量显著提高的主要原因是有效穗数和每穗粒数显著增加了16.2%和20.6%，高产优良食味品种抽穗期具有较高的叶面积指数、粒叶比更高、干物质积累总量更大。高产优良食味与高产普通食味品种虽产量水平相当，但高产途径不同，高产优良食味品种依靠更多的有效穗数，单穗重和粒重有所降低。高产优良食味品种籽粒中蛋白质和直链淀粉含量分别降低了8.8%和15.7%，是食味值显著提升的重要原因。灌浆结实期茎鞘中物质向穗部的过量转运会增加籽粒中蛋白质含量，不利于优良食味形成。本研究认为，灌浆结实期茎鞘物质向籽粒的适度转运与合理的穗部特征是平衡杂交籼稻产量与食味品质的关键因素。研究结果可为杂交籼稻高产与优良食味协同提供重要的理论依据。

Although studies on the balance between yield and quality of japonica soft super rice are limited, they are crucial for super rice cultivation.  In order to investigate the effects of nitrogen application rate on grain yield and rice quality, two japonica soft super rice varieties, Nanjing 9108 (NJ 9108) and Nanjing 5055 (NJ 5055), were used under seven N levels with the application rates of 0, 150, 187.5, 225, 262.5, 300, and 337.5 kg ha^–1.  With the increasing nitrogen application level, grain yield of both varieties first increased and then decreased.  The highest yield was obtained at 300 kg ha^–1.  The milling quality and protein content increased, while the appearance quality, amylose content, gel consistency, cooking/eating quality, and rice flour viscosity decreased.  Milling was significantly negatively related with the eating/cooking quality whereas the appearance was significantly positively related with cooking/eating quality.  These results suggest that nitrogen level significantly affects the yield and rice quality of japonica soft super rice.  We conclude that the suitable nitrogen application rate for japonica soft super rice, NJ 9108 and NJ 5055, is 270 kg ha^–1, under which they obtain high yield as well as superior eating/cooking quality.

Knowledge about crop growth processes in relation to N limitation is necessary to optimize N management in farming system. Plant-based diagnostic method, for instance nitrogen nutrition index (NNI) were used to determine the crop nitrogen status. This study determines the relationship of NNI with agronomic nitrogen use efficiency (AEN), tuber yield, radiation use efficiency (RUE) and leaf parameters including leaf area index (LAI), areal leaf N content (NAL) and leaf N concentration (NL). Potatoes were grown in field at three N levels: no N (N1), 150 kg N ha-1 (N2), 300 kg N ha-1 (N3). N deficiency was quantified by NNI and RUE was generally calculated by estimating of the light absorbance on leaf area. NNI was used to evaluate the N effect on tuber yield, RUE, LAI, NAL, and NL. The results showed that NNI was negatively correlated with AEN, N deficiencies (NNI<1) which occurred for N1 and N2 significantly reduced LAI, NL and tuber yield; whereas the N deficiencies had a relative small effect on NAL and RUE. To remove any effect other than N on these parameters, the actual ratio to maximum values were calculated for each developmental stage of potatoes. When the NNI ranged from 0.4 to 1, positive linear relationships were obtained between NNI and tuber yield, LAI, NL, while a nonlinear regression fitted the response of RUE to NNI.

In this paper, the many indices used in validation of crop models, such as RMSE (root mean square errors), Sd (standard error of absolute difference), da (mean absolute difference), dap (ratio of da to the mean observation), r (correlation), and R2 (determination coefficient), are compared for the same rice architectural parameter model, and their advantages and disadvantages are analyzed. A new index for validation of crop models, dap between the observed and the simulated values, is proposed, with dap<5% as the suggested standard for precision of crop models. The different kinds of validation methods in crop models should be combined in the following aspects: (1) calculating da and dap; (2) calculating the RMSE or Sd; (3) calculating r and R2, at the same time, plotting 1:1 diagram.

To quantify the relationships between rice plant architecture parameters and the corresponding organ biomass, and to research on functional structural plant models of rice plant, this paper presented a biomass-based model of aboveground architectural parameters of rice (Oryza sativa L.) in the young seedling stage, designed to explain effects of cultivars and environmental conditions on rice aboveground morphogenesis at the individual leaf level. Various model variables, including biomass of blade and blade length, were parameterized for rice based on data derived from an outdoor experiment with rice cv. Liangyou 108, 86You 8, Nanjing 43, and Yangdao 6. The organ dimensions of rice aboveground were modelled taking corresponding organ biomass as an independent variable. Various variables in rice showed marked consistency in observation and simulation, suggesting possibilities for a general rice architectural model in the young seedling stage. Our descriptive model was suitable for our objective. However, they can set the stage for connection to physiological model via biomass and development of functional structural rice models (FSRM), and start with the localized production and partitioning of assimilates as affected by abiotic growth factors. The finding of biomass-based rice architectural parameter models also can be used in morphological models of blade, sheath, and tiller of the other stages in rice life.