Structural patterns of tomato plants grown in greenhouse

We characterize the growth form of the two types of commercial tomato cultivars. In both types of tomato the branching is sympodial. The difference between cultivars of the indeterminate and the determined type is given by variations in the intensity in which the spatial and temporal pattern of the sympodial growth is expressed. Variations that manifests itself in the relative rate of development of each sympodial unit and in the amount of sympodial shoots that are produced during the plant's lifetime. The inflorescences of tomato plants grown in greenhouse are studied. The main inflorescences variations that have been observed are: the appearance of either dichasial inflorescences or pleiochasial inflorescences; the bracts development at the level of either the branches of the inflorescence or individual flowers; and the proliferation of the apex of the inflorescence.     

Dating fluvial processes from historical data and artifacts

Geographers have long used historical data and artifacts to reconstruct past landscapes. Many of the same data can provide powerful tools for dating stream processes over the past century or so but applications can range from months to millennia. Historical techniques are important not only to mainstream geomorphological investigations but also to fluvial applications in environmental management. The approach is useful for human-induced fluvial changes as well as for those occurring naturally. This paper is intended as an introduction to several of the primary techniques.     

青南牧区种植不同品种燕麦草的灰色综合评价

选择具有青南地区代表性的地段，采用试验种植及灰色关联分析的方法，筛选可适宜种植且生产性能较高的燕麦草品种，具有推广的实际意义。经试种和分析，丹麦４４４和丹麦４３７最好，其次为选－１８和巴燕４号，巴燕３号和黄燕麦生产性能较差。     

Dry Matter and Nitrogen Distribution at Maturity of Three Rice (Oryza sativa L.) Cultivars Exposed to Ammonia at Two Growth Stages

A substantial proportion of ammonical fertilizers applied to lowland rice is lost as gaseous N from the soil–plant system. Besides various environmental factors, the low N use efficiency of flooded rice is also attributed to this factor. As atmospheric ammonia found in the leaf environment of the plants could also be responsible for differences in N use efficiency and fertilizer N losses from lowland rice, a greenhouse study was conducted on three rice cultivars varying in physio-morphological characteristics for their dry matter and nitrogen distribution to grains at maturity in response to ammonia (NH₃) exposure at tillering and anthesis growth stages. The results revealed that ammonia exposure of plants at two growth stages did not affect the total dry matter and total N yield of the rice cultivars at maturity; however, the grain yield and grain N yield were negatively effected by NH₃ exposure of the plants at anthesis. The variation observed in dry matter and N partitioning at maturity to grains/roots of the plants exposed to NH₃ at anthesis indicated that the growth stage of the plants at which they are exposed to NH₃ has an influence on N use efficiency of crop plants and subsequent vegetative as well as total N losses from the soil–plant system.     

Some critical considerations on rice high-yielding breeding in China

Views and comments concerning rice high-yielding breeding in China had been touched upon: (1) historical development of rice breeding in China and its prominent contributions recounted; current challenges evolved from rapid population increase, erosion of key natural resources and socioeconomic changes envisaged; (2) concept of extra or super high-yielding rice breeding and related ideas embraced nowadays in the main rice-producing countries assessed; the conception of so-called superrice in China could have been misled and misunderstood, and no substantial genetical differences could be affirmed yet between superrice and modern high-yielding rice; (3) two strategical approaches of rice production and breeding in China would have been persistent in the construction of most favorable-to-growth rice fields to plant rice varieties with high-yielding potentiality as well as renovation and rejuvenation of less favorable rice fields to plant most adaptable-to-ecoenvironment varieties with promising productivity; in addition, breeding for rice varieties compatible with the specific rice regions ridden by adverse ecoenvironments; (4) overview of the relationship between the development of genetical researches and the perspective of rice breeding; integration of the classical genetical principles and breeding methods and techniques wherefrom with molecular biotechniques underscored. Finally, appeal to the breeders to adhere to due attentions to the development of genetics and promote pragmatism and traditional ethic solemnly so as to live up to implementing the national rice breeding mandates. __________ Translated from Journal of Nanjing Agricultural University, 2007, 30(1): 129–135 [译自: 南京农业大学学报]     

Influence of Soil Temperature on Seedling Emergence and Early Growth of Peanut Cultivars in Field Conditions

Peanut or groundnut (Arachis hypogaea L.) sown in early spring often has poor seed germination and seedling development. The influence of soil temperature on seedling emergence and early growth of six peanut cultivars (Florida MDR98, Southern Runner, Georgia Green, SunOleic 97R, Florunner and C‐99R) was studied in natural field soil profiles in temperature‐gradient greenhouses. We evaluated the influence of a range of soil temperatures by sowing at eight dates between January 2001 and May 2002 in Gainesville, Florida. On each sowing date, two additional temperature treatments (ambient and ambient +4.5 °C air temperature) were evaluated by sowing on either end of each greenhouse and applying differential heating. In total, 16 different soil temperature treatments were evaluated. Each treatment was replicated four times in four different greenhouses. Mean soil temperature from sowing to final emergence in different treatments ranged from 15 to 32 °C. Sowing date, temperature treatment and cultivar had significant effect on seedling emergence and development (V₂ stage). For all cultivars, the lowest germination was observed at the earliest sowing date (coolest soil temperature). Among cultivars, Florida MDR98 was the most sensitive to reduced (cool) temperature with the lowest germination and smallest seedling size at 21 days after sowing, followed by Southern Runner. Georgia Green was the most cold‐tolerant with the highest germination, followed by SunOleic 97R. There were no significant differences among cultivars for base temperature, which averaged 11.7 and 9.8 °C for rate of emergence and rate of development to V₂ stage respectively. These results imply that cultivar choice and/or genetic improvement of peanut for cold tolerance during emergence and seedling development in regions where cooler soil temperatures persist and/or regions where early sowing is desirable.     

Identification of powdery mildew resistance genes in common wheat (Triticum aestivum L. em Thell.). IX. Cultivars, land races and breeding lines grown in China

The objective of the study was to provide information about the occurrence and distribution of resistance genes in wheat cultivars, including old cultivars, land races and advanced breeding lines grown in China. Ninety-four accessions were analysed with a set of 11 differential powdery mildew isolates. Forty-four cultivars did not possess any major mildew resistance genes. Thirty cultivars revealed the response pattern of individual resistance genes. The most frequently encountered gene was Pm8, which occurred singly in 11 cultivars, combined either with Pm4a in three cultivars or with Pm4b in another three cultivars. However, 12 cultivars possessing the wheat-rye translocated chromosome pair T1BL-1RS did not express Pm8. Gene Pm2 was found in four cultivars and in combination with Pm6 in one cultivar. Genes Pm4a and Pm4b were observed in four and five cultivars, respectively. Another six cultivars carried Pm5. A gene combination of Pm2+Pm4b+Pm6 was found in one cultivar. Twelve cultivars and breeding lines exhibited a response pattern that could not be assigned to resistance genes or gene combinations present in the differential cultivars. Five out of these 12 cultivars/lines showed resistance to all the isolates tested. There is an urgent need to search for novel sources of mildew resistance in order to sustain resistance to existing and emerging powdery mildew pathogens.     

中国优质石榴品种品质比较与评价

为合理开发利用优质品种石榴资源,对我国6个主要石榴产区9个特色品种石榴果实的营养品质指标、特征性指标以及带皮压榨石榴汁的感官特性进行了测定分析和综合评价。结果表明,9个石榴品种的营养品质指标中,可溶性糖含量为10.79%~13.90%,总酸含量为2.86~11.05 g/kg,可溶性固形物含量为13.41%~16.45%,VC含量为6.33~13.83 mg/100 g,籽粒硬度为2.86~4.19 kg/cm2;果实特征指标中,浆果百粒重为25.85~70.85 g,可食率为55.12%~75.00%,果皮厚度平均值为1.40~3.33 mm,厚度差绝对值为0.02~0.94 mm;带皮压榨出汁率为35.76%~55.63%;各品种石榴果实之间的营养品质指标和特征指标均具有较大的差异。其中薄皮软籽甜石榴"甜绿籽"的综合指标优于其他品种,是鲜榨石榴汁的最佳品种。     

籼粳交超级稻甬优538的穗部特征及籽粒灌浆特性

以籼粳交超级稻甬优538为试材,常规粳稻镇稻18和杂交籼稻中浙优1号为对照,将穗部分成上部一次枝粳籽粒(UP)、上部二次枝粳籽粒(US)、中部一次枝粳籽粒(MP)、中部二次枝粳籽粒(MS)、下部一次枝粳籽粒(LP)、下部二次枝粳籽粒(LS)6个部分,比较不同类型品种的穗部特征和籽粒灌浆特性。结果表明:(1)两年中甬优538平均产量为12.5 t hm–2,较中浙优1号和镇稻18分别高17.6%和15.2%;每穗粒数和群体颖花量以甬优538最高。(2)单穗重和着粒密度以甬优538最高;甬优538穗部6个部位的籽粒数均显著高于对照品种,且以上部二次枝粳籽粒和中部二次枝粳籽粒数增加最为明显。(3)甬优538中,UP与MP、MS与US、LP与LS为同步灌浆,但两两之间为异步灌浆。中浙优1号和镇稻18中,UP、US和MP为同步灌浆,而UP、US、MP与LP、LS为异步灌浆。品种类型间,穗部6个部位米粒终极生长量的平均值以镇稻18最高,最大灌浆速率和平均灌浆速率的平均值为中浙优1号镇稻18甬优538,有效灌浆时间为甬优538镇稻18中浙优1号。     

太湖地区晚粳地方种稻米RVA谱特征多样性分析

利用50年代征集的368份太湖地区晚粳稻地方种资源材料（部分种质资源名见表1），系统测定与分析了其稻米RVA谱特征并对其多样性进行了测算。结果表明，这些种质资源的稻米RVA谱曲线特征分化明显，种质间差异极显著，呈现从籼性到糯性连续变化的特征，形成4种特征类群（见图2）。绝大多数种质（约51.9%）RVA谱的消减值在300~1 000 cP，属于典型的粳稻品种，为A类型；少量种质（如大红稻、早日黄稻、上海青、苏州青、慢红谷等）具有糯性淀粉RVA谱特征，为C类型；一些种质（如金谷黄、慢白稻、粗营洋晚稻、细叠谷、立更青）表现典型的籼稻淀粉RVA谱特征（D类型）；部分种质具有优质的RVA谱特征，即消减为负值（如天下第一种、大青种、黄谷大稻头、摇矮子、余山种等），表明种质的淀粉性质存在明显的差异。各特征值的表型遗传多样性指数均大于1，其中崩解值的遗传多样性指数达2.04。RVA谱各特征值间显著相关，并可用崩解值、消减值2个指标来简化定量描述稻米RVA谱的特征。