四川盆地9000kg hm~(-2)产量潜力小麦品种的花后冠层结构、生理及同化物分配特性

四川盆地小麦高产育种取得了突破性进展,但高产生理研究相对滞后。本研究以2011—2015连续5年的田间试验,比较了高产和一般产量潜力品种花后群体冠层结构、主要生理指标和同化物的转运分配特性,旨在揭示四川小麦9000 kg hm-2高产品种的生理基础。选择代表性高产潜力品种和一般产量潜力品种各3个,高产潜力品种产量平均9422 kg hm~(-2),比一般产量潜力品种高14.3%,增产原因是生物量或收获指数的提高。相比一般产量潜力品种,高产潜力品种旗叶短且宽,长宽比低于10,开花初期至灌浆中期叶基角和开角增加明显。开花至灌浆后期,高产潜力品种顶三叶的SPAD值及花后0 d和20 d的群体光合速率显著高于一般产量潜力品种,群体光合速率以10:00–12:00的差异最大。此外,高产潜力品种在开花期茎鞘生物量所占比例较高,而成熟期籽粒所占比例较一般产量潜力品种高1~4个百分点。籽粒产量与小麦形态、生理参数关系密切,与灌浆期旗叶基角(r=0.947,P0.01)和倒二叶基角(r=0.963,P0.01)呈正相关,与旗叶长宽比(r=-0.913,P0.01)和倒二叶长宽比(r=-0.911,P0.01)呈负相关;与开花期顶三叶SPAD值呈正相关,r值分别为0.75、0.90和0.82(P0.01);与成熟期穗轴干重比例呈负相关(r=-0.956,P0.01)。本研究表明,株高适中、株型紧凑,花后冠层叶绿素含量和群体光合速率较高,以及合理的物质分配,是高产潜力品种获得高产的生理基础。

Canopy Architecture,Physiological Characteristics and Assimilate Partitioning in Wheat Cultivars with 9000 kg hm?2 Yield Potential in Sichuan Basin

In contrast to the outstanding breeding progress of high-yield wheat in Sichuan Basin of China, the physiological basis of high-yield-potential cultivars is unclear due to seldom studies. In this study, a five-year field experiment (2011–2015) was carried out to compare the differences of canopy structure after anthesis, canopy apparent photosynthesis (CAP), chlorophyll content (SPAD), and dry matter partitioning between high-yield and normal-yield potential cultivars. Three typical high-yield and three normal-yield potential cultivars were selected, and the average yield of the high-yield potential cultivars (9422 and kg ha^-1) was 14.3% higher than that of the normal-yield potential cultivars owing to higher biomass or harvest index. Compared with the normal-yield potential cultivars, the high-yield potential cultivars had shorter and wider flag leaves (length-to-width ratio lower than 10) and showed obvious increases of basal and open angles of the topmost three leaves from early anthesis to mid-filling stage. From anthesis to late-filling stage, SPAD values of the topmost three leaves and CAP values at 0 and 20 days after anthesis were significantly higher in the high-yield potential cultivars than in the normal-yield potential cultivars, with the largest difference of CAP between 10:00 and 12:00 hour. In addition, the high-yield potential cultivars showed higher biomass proportion of stem and sheath at anthesis and higher (1–4 percentage points) biomass proportion of grain at maturity than the normal-yield potential cultivars. Grain yield was closely related to morphological and physiological parameters in wheat. For example, grain yield was positively correlated with basal angles of flag leaf (r = 0.947, P < 0.01) and the second leaf from top (r = 0.963, P < 0.01) at grain-filling stage and negatively correlated with leaf length-to-width ratios of flag leaf (r = -0.913, P < 0.01) and the second leaf from top (r = -0.911, P < 0.01). Grain yield was also positively correlated (P < 0.01) with SPAD values of the topmost three leaves (r = 0.75, 0.90, and 0.82), but negatively correlated with the proportion of spike rachis at maturity (r = ?0.956, P < 0.01). Our results indicate that moderate plant height, compact plant type, high SPAD and CAP values after anthesis, and proper dry matter partitioning are important factors in high-yielding physiology of wheat.