Influence of low temperature on grain weight during booting and grain filling period.

The experiments were carried out with japonica rice cultivar Qianchonglang 2 under pot cultivation conditions, Influences of low temperature on hull and brown rice characters of Qianchonglang 2 were analyzed. The results indicated that the low temperature during booting stage resulted in obvious decrement of the grain and brown rice length, width, area, volume and weight compared with CK (normal temperature treatments). The sizes and weights of superior and middle grains reduced obviously by low temperature at leaf-remainder 1.0 time, and the inferior grains were at leaf-remainder 0 time, and weights of superior, middle and inferior grains were 10.84%, 12.99% and 16.77% lower than that of the control, respectively. Grain plumpness decreased by low temperature treatment during booting and grain filling period, and the visible effect of grain plumpness were founded from sixteen to twenty days after heading. Grain sizes had a closer relationship with grain weight than with grain plumpness, and the 1000-grain weight increased with the grain length, width and area increase.