Effects of Controlled-Release Fertilizers and Their Application Methods on Germination and Seedling Growth of Dent and Sweet Corns

Effects of controlled-release fertilizers (CRFs) (C-AS, polyolefin coated ammonium sulfate, 50-day-type; Dd-LP, polyolefincoated urea with dicyandiamide, 40-day-type; C-ANP, polyolefin coated ammonium nitrate phosphate, 40-day-type; andC-DAP, polyolefin coated diammonium acid phosphate, 40-day-type), ammonium sulphate and no fertilizer control, andtheir application methods (spot, band, surface and mixed) on germination and seedling development of sweet corn (Zeamays L.var. saccharata Sturt.) and dent corn (Zea mays L.var. indentata Sturt.) were investigated in a greenhouse. Underco-situs application (band and spot) of CRFs, there were no obvious differences in the germination speed and rate for bothdent corn and sweet corn relative to control. Mortality rates of sweet corn seedlings under co-situs application were highin experiment 1, but were very low in experiment 2, because the environmental conditions were different in the twoexperiments. That is, under lower temperature and weaker sunlight, young seedlings easily die due to high soil nutrientconcentration and slow growth speed of corn. Shoot weight of both dent and sweet corn did not greatly decrease inexperiment 1. In experiment 2, there were no significant differences in shoot and root weight of both corns between co-situs and surface or mixed application methods. However, with spot and band application of ammonium sulfate, shoot androot weight were significantly reduced. Soil EC and pH were considerably affected by co-situs application, especially atthe fertilizer application site. For both dent and sweet corn, EC in the 0-3 cm soil was significantly higher under co-situsapplication and surface application than that under mixed application, whereas in the 3-6 cm soil depth the situation wasreversed. Compared with control, mixed application of CRFs decreased soil pH slightly (0-3 cm depth) or greatly (3-6 cmdepth).

普通×爆裂玉米自交系F_7重组近交系植株性状初步分析

利用普通玉米自交系丹232与爆裂玉米自交系N04为亲本构建了含有259个家系的重组近交系(RILs)群体,对株高、穗位高、顶高、顶高/株高、茎粗、穗上位叶片数、叶面积、雄花分枝数、雄穗长9个植株性状初步分析。结果表明:RILs群体各性状分离明显,且基本符合正态分布,表现为数量性状遗传特点,是一个较为理想的作图群体。但RILs系内各性状都存在不同程度的变异,需要增加自交代数。

硬粒马齿爆裂型玉米遗传关系的SSR标记研究

利用SSR标记研究了硬粒型、马齿型玉米与爆裂玉米自交系的亲缘关系。用23对扩增带型稳定的SSR引物,从供试材料中检测出100个等位基因变异,每对引物检测等位基因2～10个,平均4.35个。SSR引物的PIC介于0.4261～0.8877之间,平均多态性信息量为0.691。按UPGMA法对43份玉米自交系进行聚类分析。聚类分析表明,爆裂玉米、硬粒型玉米以及马齿型玉米自交系并不能严格地划分为3大类,但爆裂玉米与其余两类玉米自交系遗传距离均较大。此外,硬粒型玉米和爆裂玉米自交系间的平均遗传距离与马齿型玉米和爆裂玉米自交系间的平均遗传距离在0.01水平上差异极显著。在硬粒型玉米、马齿型玉米、爆裂玉米3类种质中,硬粒型玉米与爆裂玉米自交系亲缘关系较为接近。

普通×爆裂玉米RILs群体籽粒不同发育时期品质性状及其相关分析

为了探索籽粒品质性状的动态发育规律和相关性,为相关性状的分子发育机理解析和遗传改良提供理论依据。利用普通玉米自交系丹232与爆裂玉米自交系N04为亲本构建的重组近交系（RILs）群体为材料,对籽粒不同发育时期的粗蛋白、粗淀粉、粗脂肪和赖氨酸4个品质性状分析。结果表明：RILs群体各时期4个品质性状均存在明显的超亲分离;亲本、F1及RILs群体的粗蛋白、粗脂肪及赖氨酸含量从授粉后10~30天持续下降,至灌浆后期又表现不同程度的升高,而粗淀粉含量在整个发育时期持续增加。除粗蛋白含量授粉后10天与40天间、粗脂肪含量授粉后10天与30天间不相关外,其余各性状在不同发育时期均表现为显著或极显著正相关。粗淀粉与粗蛋白、粗脂肪及赖氨酸在4个时期表现为极显著负相关,其余性状间均表现为极显著正相关。因此,在玉米品质育种中,应注意协调各性状间的相互关系。