不同熟期玉米品种籽粒田间脱水特征差异性分析

Characteristic difference in grain in-field drydown between maize cultivars with various maturation

玉米收获期籽粒含水率是影响机械粒收质量和籽粒品质的重要因素,不同熟期品种收获期籽粒含水率有差异,同时品种间熟期的差异也使其田间脱水的环境不同,造成其脱水特征难以精准比较。本研究于2018—2019年,以不同熟期玉米品种为研究对象,设置间隔约10 d的8个播期处理,播期覆盖自早春播至晚夏播,创制籽粒田间脱水的环境差异,观测籽粒含水率动态过程,分析品种之间籽粒田间脱水特征差异。结果表明,收获期籽粒含水率与品种生育期长短呈显著正相关(r=0.810^(*),2018;r=0.912^(**),2019),早熟品种收获时含水率低、晚熟品种高;生理成熟期籽粒含水率与灌浆期长短呈显著负相关(r=-0.484^(**)),早熟品种生理成熟期籽粒含水率高、晚熟品种低;籽粒生理成熟前脱水速率(r=-0.655^(**))和生理成熟后脱水速率(r=-0.492^(**))均与生育期长短呈显著负相关,表现出早熟品种籽粒脱水速率快、晚熟品种脱水速率慢的特征;籽粒生理成熟前脱水速率与生理成熟后脱水速率之间呈显著正相关(r=0.466^(**)),一般而言生理成熟前籽粒脱水速率较快的品种,生理成熟后脱水速率也较快,但是存在生理成熟前脱水速率快、生理成熟后脱水速率慢的特例品种。本研究认为生育期影响籽粒脱水速率,通常早熟品种生理成熟前、后籽粒脱水速率均较快,收获期含水率较低;晚熟品种生理成熟前、后籽粒脱水速率均较慢,收获期含水率较高;但是存在特例品种,在进行籽粒快速脱水品种的选育和筛选时应引起关注。

The grain moisture concentration at harvest stage varies vastly among maize cultivars with various maturities,which is an important factor affecting mechanical grain harvesting and grain quality.Differences in maturation result in various environmental conditions for grain drying in the field,thus increasing the difficulty of comparing the characteristics of grain dehydration between cultivars.Maize cultivars with different maturities were seeded eight times at 10-day intervals from early spring to late summer in 2018 and 2019,supplying the different environmental conditions for grain in-field drying.The dynamics of grain moisture concentration were measured for all cultivars to analyze varietal differences in characterization of grain in-field drydown.Grain moisture concentration at harvest was positively correlated to growth period(r=0.810^(*),2018;r=0.912^(**),2019).Usually,the early-maturing cultivars had lower moisture concentration at harvest stage than the late-maturing cultivars.Grain moisture concentration at physiological maturity was negatively correlated to grain filling period(r=-0.484^(**)).It was higher for early-maturing cultivars than late-maturing cultivars.Grain moisture loss rates of pre-(r=-0.655^(**))and post-maturity(r=-0.492^(**))were both inversely associated with the growth period,and were faster for early-than late-maturing cultivars.Furthermore,there was a significantly positive correlation between the grain moisture loss rate of pre-maturity and post-maturity(r=0.466^(**)).Overall,the cultivars with high moisture loss rate before maturity declined moisture quickly after maturity,while there was the particular cultivar with high moisture loss rate before maturity but low moisture loss rate after maturity.Duration of growth period affected grain dehydration rate.Generally,compared to late-maturing cultivar,grain of early-maturing cultivar had faster drying rates of pre-and post-maturity and lower moisture concentration at harvest stage.However,there was the noticeable case of particular cultivar when breeding and screening maize with rapid grain dehydration.