杂交中稻开花期高温对结实率影响及其与组合间库源结构和开花习性的关系

Effects of High Temperature during Flowering Period on Seed Setting Rate and Its Relationship with Sink to Source Ratios and Flowering Habit of Mid-season Hybrid Rice

2011—2013年,以50个杂交中稻组合为材料,通过大田分期播种与智能人工气候室控温,以使开花期遇高温伤害,研究了杂交组合开花期的耐高温特性与库源性状及开花习性的关系。结果表明,杂交组合间耐高温能力差异显著,鉴定出了开花期常温下结实率和耐高温指数均较高的组合10个,即绵香优576、蓉稻优415、香绿优727、绵优5240、川谷优202、川优6203、冈优169、内香优5828、川谷优7329、江优126。开花期耐高温能力与开花当时植株光合物质的供给水平有关,有效穗数越少的组合的穗粒数和粒叶比越高,即单位颖花的光合源占有量越少,以致开花期耐高温指数与粒叶比呈显著负相关;9:30—11:00时段开花比例和叶绿素含量分别与耐高温指数呈显著正相关。选用穗数型、花时早而集中的杂交组合和提高开花期叶绿素含量,是增强杂交水稻开花期耐高温能力的重要途经。

From 2011 to 2013, under the condition of high temperature injury during heading stage designed by applying different sowing dates in the field and controlling the temperature in intelligent artificial climate chamber, the relationship high temperature resistance index （HTRI） with sink to source ratio and flowering habit in mid-season hybrid rice was studied with 50 hybrid combinations as tested materials. By using variance, correlation and regression analyses, the results showed that there were significant differences in HTRI among hybrid combinations. Ten of the combinations were tested to show a higher levels of seed setting rate and HIRI during flowering stage, including Mianxiangyou 576, Rongdaoyou 415, Xiangl＆#252;you 727, Mianyou 5240, Chuanguyou 202, Chuanyou 6203, Gangyou 169, Neixiangyou 5828, Chuanguyou 7329, and Jiangyou 126. There existed a sig-nificant relation between HTRI and carbohydrate supply level during flowering stage. The smaller the number of effective panicles of hybrid combinations was, the higher the spikelets per panicle and grain-leaf ratio would be, namely, the less the occupancy of photosynthetic source per spikelets would be. As a consequence, significantly negative correlation were observed between HTRI and grain-leaf ratio during flowering stage. The flowering ratio from 9：30 to 11：00 and chlorophyll content of leaf had a significantly positive correlation with HTRI respectively. Choosing the hybrid combinations with a larger number of effective panicles and early intensive anthesis and raising the level of chlorophyll content of leaf are the vital ways to enhance HTRI during heading stage.