The objective of this study was to ascertain the characteristics of the grain-filling and physiological indexes after head-ing and the yield components of super rice with different panicle-grain types. An experiment with different sowing date was con-ducted using different growth duration varieties (Zhunliangyou 527, Liangyoupeijiu, Y-liangyou 1, Yuxiangyouzhan, and Huanghuazhan) under the field conditions to ensure the grain filling was under the similar temperature and solar radiation condi-tions. The grain yield and its components averaged in three sowing treatments displayed significant difference among tested varieties, of which the highest yield reached 9.47 t ha–1 for Liangyoupeijiu and the lowest was 8.39 t ha–1 for Yuxiangyouzhan. According to the hierarchical cluster analysis based on the grain number per panicle and 1000-grain weight, tested varieties were divided into the big grain type (Zhunliangyou 527), the medium grain type (Liangyoupeijiu and Y-liangyou 1), and the small grain type (Yuxiangyouzhan and Huanghuazhan). There were obvious differences intensity and peak duration of grain filling among the tested varieties. The big grain variety showed quick grain growth at the beginning, high intensity and short peak duration for grain filling during the middle-late periods, being one step filling in the upper, middle and lower branch grains; the medium grain variety showed quicker grain growth at the beginning, smaller intensity and longer peak duration for grain filling during the middle- late periods, with two filling peaks from 12 d to 18 d and from 24 d to 30 d after heading, respectively; the small grain variety showed slow grain growth at the beginning, smaller intensity and shorter peak duration for grain filling during the middle-late periods, which was one step filling in the upper or middle branch grains and two step filling in the lower branch grains. The ave-rage grain filling rate closely related to the panicle-grain type of varieties, was 0.68 mg d–1 for big grain variety, 0.48–0.51 mg d–1 for medium varieties, and 0.41–0.47 mg d–1 for small grain varieties. The intensity and duration of the grain-filling also associated with the changes of physiological indexes of flag leaf and roots after heading. At the beginning of the grain-filling, chlorophyll content, chlorophylla/b ratio, carotenoids content gradually declined, leaf soluble sugar content, MDA content gradually in-creased, POD and CAT activities and root activity successively underwent two rise and fall processes. In conclusion, different panicle-grain types super rice have significantly different characteristics of yield components and grain filling. The intensity and the duration of grain-filling depend upon the panicle-grain type of varieties and the branch and grain positions inserted on the panicle, with the same tendency of physiological indexes variation in flag leaf and roots.%为探明不同穗粒型超级稻产量构成特点、籽粒灌浆特性及其与后期生理指标的关系。以不同生育期品种准两优527、两优培九、Y两优1号、玉香油占、黄花占为试验材料,在大田栽培条件下分期播种以确保不同生育期品种在相似的温光条件下灌浆结实。结果表明,不同播期平均产量及其构成因子的品种间差异显著,以两优培九产量最高(9.47 t hm–2),玉香油占产量最低(8.39 t hm–2)。依据每穗粒数和千粒重系统聚类分析,可将品种分为大粒型(准两优527)、中粒型(两优培九、Y两优1号)和小粒型(玉香油占、黄花占)。籽粒灌浆强度及持续时间的品种间差异明显。其中,大粒型品种籽粒灌浆起步快、强度大、峰值持续时间短,上、中、下部枝梗籽粒均为一段式灌浆；中粒型品种籽粒灌浆起步快、强度较小、峰值持续时间长,其上部枝梗籽粒为一段式灌浆,中、下部枝梗籽粒为两段式灌浆,高峰值分别在抽穗后12~18 d和24~30 d；小粒型品种籽粒灌浆起步慢、强度小、峰值持续时间长,其上、中部枝梗籽粒为一段式灌浆,下部枝梗籽粒为两段式灌浆。平均籽粒灌浆速率与品种的穗粒类型密切相关,其中,大粒型品种为0.68 mg d–1,中粒型品种为0.48~0.51 mg d–1,小粒型品种为0.41~0.47 mg d–1。籽粒灌浆强度及持续时间与后期剑叶、根系生理指标有关,籽粒灌浆启动后,叶绿素含量、叶绿素a/b值、类胡萝卜素含量逐渐降低,剑叶可溶性糖含量、MDA含量逐渐上升, POD活性、CAT活性及根系活力先后出现2次升降过程。可见,不同穗粒型超级稻品种产量构成及籽粒灌浆特点的差异明显,籽粒灌浆强度及持续时间与品种的穗粒型及枝梗着生的部位有关,也与后期剑叶及根系衰老生理指标的变化趋势一致。
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