喷气织机改品种接经法

众所周知,分绞接经上轴法比穿经上轴法要省工省时。在新、原品种穿综丝、停经片方法相同或可变为相同,纱线号数相同或接近,使用相同的综、片的情况下,改品种也可应用分绞接经上轴法。若应用巧妙,则喷气织机改品种由难变易,甚至易于有梭织机。如果新、原品种符合上述条件。

榆林市退耕还林山杏低效林品种改优技术

介绍了榆林市退耕还林山杏低效林的品种改优技术,包括换头前准备、嫁接品种和时间、人员安排、嫁接后管理等方面内容,以为榆林市山杏低效林改造提供参考。

浅谈肃州区退耕还林山杏低效林品种改优技术

介绍了肃州区退耕还林山杏低效林的品种改优技术,包括换头前准备、嫁接品种和时间、人员安排、嫁接后管理等方面内容,以为肃州区山杏低效林改造提供参考。

原州区退耕还林山杏低效林品种改优技术

介绍了固原市原州区退耕还林山杏低效林的品种改优技术,包括换头前准备、嫁接品种和时间、人员安排、嫁接后管理等方面内容,为原州区山杏低效林改造提供参考。

苹果老果园改造技术

老果园存在着品种落岳、树冠郁闭、内膛枝梢干枯衰老、结果能力差，产量及品质降低等问题，通过“二改一减一加强”的措施对老果园进行改造，使果园品种得以改良、品质得以提升、树势得以恢复。

Changes in Agronomic Traits of Indica Hybrid Rice during Genetic Improvement

[Objective]The aim was to elucidate the changes of agronomical traits of indica hybrid rice during its genetic improvement.[Method]23 typical indica hybrid combinations cultivated in the middle and lower reaches of Yangtze River during the last 30 years were selected as experimental materials.All the hybrid rice combinations were grown in the same field;and then yield and morphological characters of single plant were compared;correlation and path analyses among agronomic characteristics were also conducted.[Result]During the 30 years of genetic improvement,the effective panicle number per plant was progressively decreased,which caused the decrease of grain yield and biomass per plant of hybrid rice combinations in spite of the slightly increased plant height,1 000-grain weight and number of grains per panicle.Although the transformation percentage of the matter in stem and sheath decreased after flowering,leave photosynthetic capacity after flowering was increased as panicle weight.Correlation and path analysis showed that although both biomass per plant and number of grains per panicle were significantly correlated with grain yield per plant,biomass per plant acted as the key factor affecting yield per plant.[Conclusion]It was suggested that in rice high yield cultivation,panicle number was as important as large panicle,and tillering ability should not be neglected in breeding.

固原市原州区红梅杏嫁接育苗技术探讨

介绍了固原市原州区退耕还林山杏低效林的品种改优技术,包括换头前准备、嫁接品种和时间、人员安排、嫁接后管理等方面内容,为原州区山杏低效林改造提供参考。

Research on Oxalate Oxidase and Its Genes in Plants

This paper introduces the discovery,composition and structure of oxalate oxidase,as well as illustrates the biological functions of this enzyme.With a comprehensive introduction upon previous researches upon gene cloning and heredity transformation of this enzyme,it indicates that heredity transformation can increase the content of oxalate oxidase within the plants and also enhance their resistance.The paper also points out the problems such as lack of gene resources and difficulty in the transformation of heterologous genes,and the focus in later researches should be laid upon the exploration of plant resources relative to this enzyme and selection of resistant species.

Impediments to New Improved Maize Variety Testing and Release in Selected Countries in Sub-Saharan Africa

Before farmers can benefit from new improved maize varieties with novel genetic information, new maize varieties have to undergo performance testing, registration and approval. The registration procedures require that new maize varieties must pass the tests for value for cultivation and use （VCU） and standardized tests for distinctness, uniformity and stability （DUS）. To meet the minimum requirements for variety release, public and private sector maize breeding programs routinely assemble breeding nurseries and evaluate variety performance in National and Regional Performance Trials （NRPT） with the objective of generating important agronomic data to identify the best maize varieties for release. In spite of intensive variety evaluation in regional and national trials, only few maize varieties have been registered and released annually in sub-Saharan Africa （SSA） denying farmers access to new improved varieties. The purpose of this study was to identify constraints hampering the registration and release of elite maize gennplasm and make recommends on how to quicken the deployment of elite germplasm to smallholders＇ farmers. A survey was conducted on the varietal testing and release systems in 14 selected countries （Angola, Benin, Ethiopia, Malawi, Ghana, Mali, Mozambique, Nigeria, Tanzania, Kenya, South Africa, Uganda, Zambia, and Zimbabwe） in SSA. The results from the study show that regulations on variety testing and release procedures in the various countries are overlapping and rigid hindering the deployment and commercialization of new improved maize germplasm. The study also showed that varietal release rates fluctuated between countries with South Africa having the highest number of varietal release rates per year and some countries failing to release a single variety per year.

Behavioral Differentiation between Anas poecilorhyncha and Domestic Duck

Anas poecilorhyncha is one of improved variety of mallards, which was the protected bird species listed by International Union for Conservation of Nature （1UCN）. Little is known until now about behavioral characteristics of the mallard. The objective of this study was to compare the behavioral differentials between A. poecilorhyncha and domestic duck in order to make a strategy to manage A. poecilorhyncha under the condition of animal welfare. A total of 180 birds were distributed into six groups with 30 birds for each group. They were placed in a room of 3 m ~ 4 m and fed for one year old. Sansui ducks, a kind of native domestic duck （Sansui laying duck） were used for behavioral comparison. Two different rooms in the same building were applied, one room for A. poecilorhyncha and another one for Sansui ducks. All behaviors for A. poecilorhyncha and Sansui ducks were coded using the program The Observer XT 11.5 （Noldus Information Technology, Beijing）. The duration of observation was from 8：00 am to 18：00 pm daily and lasted 5 d. The results showed that there were similar behavioral percentages between A. poecilorhyncha and domestic duck. Percentages of standing activity spent for A. poecilorhyncha and Sansui duck were 34.59% and 30.25%, respectively. Accordingly, the activities, such as wing plugging, preening and head stretching, were more than 5.51%. The other activities, including walking, drinking and tail wagging, occupied less proportions （〈 3%）. While the specific behaviors, like aggression, alerting, wing dithering, clawing, nodding, pendulum clawing and crawling, took less than 1% of percentage. There were large differences between A. poecilorhyncha and domestic duck when comparing eight behavioral peaks. Lag sequential analysis was used to calculate frequency of transition between a pair of activities. Some parameters were very significant, like the frequency value from foraging converted to drinking in Sansui duck was 369-515, but 37-65 in A. poecilorhyncha. The best explaining could be given that Sansui duck was better domesticated than spot-billed duck. This study provides the basic data to study and develop spot-billed duck.

Economic Impact of Mutant Cassava （Manihot Species） for Agricultural Improvement in Ghana

The importance of agricultural innovations for raising the living standards of farmers has received substantial attention from the economic and political communities. In Ghana, cassava serves as an important source of calorie and cash crop. Production constraints such as the cassava mosaic disease caused by virus have limit farmers access to productivity potentials and marketing. Breeding efforts attempting to address this constraints have had some success such as the mutant Tech Bankye virus resistant variety. This research, therefore, analysed the impact of some production input on mutant cassava productivity growth in Ghana with the use of Cobb-Douglas production function. Results show that farmers cultivate the mutant variety in addition to other traditional varieties to averse risking in marketing and income. The average cost of production of the mutant variety is higher compared to that of the traditional variety. Eighty percent of the farmers complained difficulty in accessing market for the mutant variety because it could not replace the traditional variety in terms of its texture for the local native ＂fufu＂ production and ＂ampesi＂ and also deteriorate quickly in storage. However, for industrial production of ＂gari＂ and starch, the mutant is the best. Both the mutant cassava and the traditional varieties showed increasing returns to scale, however, the returns to scale of the mutant variety were lower compared to that of the traditional variety. Also, the opportunity cost of forgoing the traditional varieties to cultivating the mutant variety was very high making adopted farmers hesitant to continue it cultivation.

Evaluating the Impact of Adoption of Improved Maize Varieties on Yield in Uganda： A Propensity Score Matching Approach

The main objective of this study was to evaluate the impact of adopting improved maize varieties on crop yield in Uganda using propensity score matching （PSM） algorithms to control for hidden selection bias. The study employed cross-sectional household data collected in 2005/2006 by the Uganda Bureau of Statistics （UBOS） across the country. Data were divided into two parts; the full sample and smallholder farmer sub-sample （those that cultivated less than 5 acres or 2 Hectares of maize in 2004 and 2005）. Then estimation was made of the difference in yields between the adopters and non adopters, the average treatment effect on the treated （ATT） for the full sample and smallholder farmer sub-sample. Matching methods were used to control for hidden selection bias and the standardized bias measure was used to check for the quality of matching. The results indicate that adoption of improved maize seed had a robust positive and significant effect on yields obtained by farmers. The results were consistent for both the full and smallholder farmer sub-samples. Sensitivity analysis using Rosenbaum bounds indicated that the ATT results were fairly robust to hidden selection bias. That is, the results were not sensitive to unobserved selection bias. Therefore it is confidently asserted that the estimated average difference in maize yields between the adopters and non-adopters was due to the effect of planting improved maize seed.

PROPER REPARAMETRIZATION FOR INHERENTLY IMPROPER UNIRATIONAL VARIETIES

In this paper, a class of lattice supports in the lattice space Zm is found to be inherently improper because any rational parametrization from Cm to Cm defined on such a support is improper. The improper index for such a lattice support is defined to be the gcd of the normalized volumes of all the simplex sub-supports. The structure of an improper support S is analyzed and shrinking transformations are constructed to transform S to a proper one. For a generic rational parametrization RP defined on an improper support S, we prove that its improper index is the improper index of S and give a proper reparametrization algorithm for RP. Finally, properties for rational parametrizations defined on an improper support and with numerical coefficients are also considered.