高粱不同分类组杂种优势和配合力的研究

以３份高粱不育系和２４份恢复系组配的７２个杂交种及其亲本为试材，研究了不同高粱分类组的杂种优势和配合力。结果表明，７种性状的总平均优势为１２１．５％。株高和穗长正优势占９８．６％和９７．１％，产量和产量组分在５２．８％～８１．９％之间，出苗至５０％开花日数负优势占８７．５％。不同分类组小区产量、穗粒重和穗粒数的杂种优势差异较大，除穗粒数外，顶尖族组和混合族组的平均超高亲优势水平和次数都高于都拉族组。顶尖族组的ＳＣ７２６１４和ＳＣ５４１４，都拉族组的Ｓ２１０１４和混合族组的ＳＣ３７０１４和Ｓ１１０１４Ｅ的产量及其多数产量组分具一般配合力正效应，并达到显著或极显著平准。在１０个最高产杂交种中，父本是顶尖族的６个，属顶尖工艺群；父本是混合族组的４个，分属惹拉—惹拉、顶尖—考拉和浅黑—菲特瑞塔工艺群。因此，从顶尖族和混合族组里选择亲本更易获得强优势杂交种。     

美国高粱种质资源的收集和利用

美国是世界上高粱主要生产国家之一,其总产量占世界高粱总产量的25％左右,平均单产为每公顷4386公斤。在美国,高粱只有一百多年的栽培历史。美国最早的高粱品种是由非洲移民带进的卡佛尔谷等。这些品种虽然具有抗旱性和稳产性,但产量不高,而且植株偏高难于收获。于是,美国开始从世界各地广泛收集高粱种质资源,并实施品种改良计划,新的改良品种和杂交种不断出现,推广应用后使单位面积产量大幅度提高,子粒产量由50年代的每公顷1200公斤上升到80年代的3800公斤。     

中美高粱杂种优势与配合力研究

中美高粱杂种优势与配合力研究卢庆善Ｋ．Ｆ．Ｓｃｈｅｒｔｚ￣２，ＵＳＤＡ－ＡＲＳ￣２，宋仁本，郑春阳（辽宁省农业科学院高粱研究所ＴｅｘａｓＡ＆．ＭＵｎｉｖｅｒｓｉｔｙ，ＣｏｌｌｅｇｅＳｔａｔｉｏｎ，Ｔｘ７７８４３，Ｕ．Ｓ．Ａ．）中国高粱杂种优势利用的历...     

Molecular and morphological supertrees for eutherian (placental) mammals

A large body of diverse comparative data now exists for a major phylogenetic synthesis of the higher-level relationships among eutherian (placental) mammals. We present such a phylogenetic synthesis using the composite trees or supertrees from the combined and separate analyses of their published molecular and morphological source phylogenies. Our combined and separate supertrees largely support the same suprafamilial taxa and orders, but different interordinal clades. These similarities and differences reinforce the continuing contributions of morphological studies, while highlighting the growing influence of molecular information on the field. As current summaries of past research, our supertrees emphasize opportunities for future work, while providing a step toward the eventual integration of the data and characters themselves.     

Convergent domestication of cereal crops by independent mutations at corresponding genetic Loci

Independent domestication of sorghum, rice, and maize involved convergent selection for large seeds, reduced disarticulation of the mature inflorescence, and daylength-insensitive flowering. These similar phenotypes are largely determined by a small number of quantitative trait loci (QTLs) that correspond closely in the three taxa. The correspondence of these QTLs transcends 65 million years of reproductive isolation. This finding supports models of quantitative inheritance that invoke relatively few genes, obviates difficulties in map-based cloning of QTLs, and impels the comparative mapping of complex pheno-types across large evolutionary distances, such as those that separate humans from rodents and domesticated mammals.     

Apospory in Sorghum bicolor (L.) Moench

A line of Sorghum bicolor (L.) Moench was discovered to reproduce by apospory, a type of apomixis. The formation of an embryo by a nucellar cell without fertilization was establshed by cytological observations of ovaries and by progeny tests.     

Profiling and characterization antioxidant activities in Anoectochilus formosanus hayata

Phytochemical characteristics and antioxidant activities of the crude and fractionated plant extracts of Anoectochilus formosanus were evaluated using five different assay systems. An acid-treatment (2 N HCl in 95% ethanol) was employed to treat a butanol fraction (BuOH), creating an acid-hydrolyzed BuOH fraction. The IC(50) values for DPPH radicals in the BuOH and acid-hydrolyzed BuOH fractions were 0.521 and 0.021 mg/mL, respectively. The acid-hydrolyzed BuOH exhibited approximately 5-fold higher activity in scavenging superoxide anion than catechin. The acid-hydrolyzed BuOH fraction also effectively protected phi x174 supercoiled DNA against strand cleavage induced by H(2)O(2) and reduced oxidative stress in HL-60 cells. Metabolite profiling showed that the aglycones of flavonoid glycosides in BuOH were produced after acid hydrolytic treatment, and this resulted in a significant increase in antioxidant activities of acid-hydrolyzed BuOH. One new diarylpentanoid, kinsenone, and three known flavonoid glycosides and their derivatives were identified for the first time from A. formosanus, with strong antioxidant properties.