不同小麦品种粒重和蛋白质含量的穗粒位效应分析

小麦籽粒的发育存在时空差异,不同穗粒位的粒重和蛋白质产量也存在差异,剖析粒重和籽粒蛋白质含量的穗粒位效应,有助于深入了解小麦产量和品质的形成机制。于2009—2010和2010—2011小麦生长季进行大田试验,选用3种类型4个品种,分析了不同穗粒位的粒重、蛋白质积累和蛋白质含量的动态变化。结果表明,粒重和蛋白质积累量的穗粒位间变异大于年份(环境)间变异和基因型间变异;蛋白质含量的年份间变异大于基因型间变异和穗粒位间变异,而成熟期穗粒位间变异最大。大粒品种易受环境影响,小粒品种比较稳定。优质面包小麦品种开花后各时期的籽粒蛋白质含量普遍高于中筋小麦,但不同时期、不同年份差异较大。开花后各时期,强势粒的粒重、蛋白质积累量和蛋白质含量显著大于弱势粒,中部籽粒显著大于上部和下部籽粒;随着灌浆进程穗中部与下部籽粒的差异变小,至开花后36 d时,中部和下部籽粒的蛋白质含量无显著差异。随籽粒灌浆进程,不同品种各穗粒位的粒重和蛋白质积累均呈"慢–快–慢"的"S"型曲线变化,蛋白质含量均呈"高–低–高"的"V"型曲线变化,灌浆后期,中部和下部强势粒以及下部弱势粒的蛋白质含量增长速度明显快于其他穗粒位籽粒。粒重最大生长速率出现在开花后18~21 d,快速增重时期为开花后12~26 d;籽粒蛋白质最大积累速率出现在开花后21~24 d,快速积累时期为开花后13~32 d。根据本研究结果,我们认为高产优质小麦品种的特征是籽粒不宜过大,小花位粒数不宜过多,且中、下部籽粒较多,开花后13~26 d灌浆速率快。

Effects of Spikelet and Grain Positions on Grain Weight and Protein Content of Different Wheat Varieties

Wheat seeds are developed in a spatial-temporal order resulting in different grain weights and protein contents in different positions of spike. Dissecting the position effect of grain weight and protein content is helpful to go into the mechanism of yield and quality formation. This study was carried out in the 2009–2010 and 2010–2011 winter wheat seasons with four varieties in three quality types. The dynamic changes of grain weight, protein accumulation and protein content were measured according to spikelet–grain position. Variations of grain weight and protein accumulation affected by spikelet–grain position were greater than those by environment (year) or genotype. Variation of protein content affected by environment was larger than that by genotype or spikelet–grain position, however, the spikelet–grain position was the first affecting factor at maturity stage. Large-grain variety was more sensitive to environment, whereas, small-grain variety was relatively stable. During grain filling, the protein content of strong-gluten wheat was higher than that of medium-gluten wheat, and influenced greatly by filling stage and environment. The single grain weight, protein content, and protein accumulation of superior grains were significantly higher than those of inferior grains during the grain-filling period, and the mid-position grains were significantly superior to the upper- and lower-position grains. However, the difference between mid- and lower-position grains became smaller with the filling process, until no significant difference in protein content at maturity stage (36 days after flowering). The dynamics of single grain weight and protein accumulation showed an “S” curve of slow–fast-slow changing trend and the dynamics of protein content showed a “V” curve, in spite of genotype or spikelet–grain position. During late filling stage, the supervisor grains in mid- and lower-positions, as well as inferior grains in lower-position had faster increase of protein content than grains in other positions. For grain weight, the maximum growth rate appeared at 18–21 days after flowering, and the rapid growth period appeared at 12–26 days after flowering. For grain protein, the maximum accumulation rate appeared at 21–24 days after flowering, and the fast accumulation period was from 13 to 32 days after flowering. It is concluded that moderate grain size and floret number are important for high-yield and high-quality wheat breeding, and an appropriate increase of the mid- and lower-position grains may accelerate grain-filling speed at 13–26 days after flowering.