高密度劣质板栗低产果园改造模式的初步研究

采用随机区组试验设计法,对高密度劣质板栗低产果园的不同改造模式进行了试验研究,结果表明：高密度劣质板栗低产果园的不同改造模式之间的产量差异极显著,以嫁接换冠＋间伐为最佳,板栗园产量高、品质好、经济效益好。     

低温和超低温保存花粉对番茄坐果率和种子量的影响

为了研究不同处理下长期保存花粉对番茄坐果率和种子量的影响,本文以云南农业大学园林园艺学院选育的Ryau96172I和Ryau9327D两个番茄品系为试材,采用低温(4℃,处理I)及超低温(-196℃,处理II)条件保存花粉,以常温作为对照(CK),对不同处理的花粉人工授粉(60朵花)后的坐果率、种子总重量、平均单果种子重量、种子总数及单果种子平均数进行比较分析.结果显示:与对照相比,处理I和处理II人工授粉后对番茄的坐果率无显著差异;处理I人工授粉后番茄的种子总重量、平均单果种子重量、种子总数及单果种子平均数无明显差异,但处理II人工授粉后其相应指标显著偏低(P0.05).结果表明: 超低温处理下保存花粉对番茄的种子量有较大影响.     

区域土地资源人口承载力理论模型及实证研究

\t\t\t\t\t目的\t\t\t\t\t研究云南省盈江县的耕地生产潜力及产量差,为该区域的土地利用、资源保障、经济发展等提供重要的支撑作用。\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t以盈江县耕地地力调查数据为基础,利用ArcGIS 10.0软件对基础数据进行转换、叠加及分析,重点关注研究区域中耕地地块的属性,利用生产潜力计算模型分析盈江县耕地生产潜力,并根据耕地的实际产量数据分析其产量差。\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t盈江县耕地生产潜力主要分布在9.46~24.87 t/hm²之间,县域均值为14.17 t/hm²,区域差异较大。产量差分布在16.18%~87.58%之间,县域均值为64.30%。从空间分布角度,县域内区域间的耕地生产潜力及产量差呈现出较大的区域差异,具有明显的区域分布特征,即生产潜力较高的区域主要分布在太平镇、平原镇、弄璋镇等大盈江流域,产量差较高的区域主要分布在盏西镇、勐弄镇、昔马镇等盈江县中、北部区域。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t利用ArcGIS对耕地生产潜力及产量差研究,其研究数据可以根据耕地地力调查周期、耕地的实际产量及时的更新,研究结果贴合研究区域实际情况,对于提高农业产出、促进区域农业可持续发展具有积极的意义。\t\t\t\t     

早春小拱棚黄瓜栽培,何时定植好? 怎样使其缓苗快,长势旺?

1小拱棚黄瓜栽培特点塑料薄膜小拱棚早熟栽培黄瓜的适宜定植期为3月下旬。定植后黄瓜缓苗快慢、长势好坏是由许多环境因素共同作用的结果,其中最主要的是根系生长得好坏。实际上,每当观察地上部生育状态时,应当首先想到根系发育如何,有些症状表现在地上的冠部,但问题的根源却存在于地下部的根系上。     

Partial resistance to neck blast influenced by stage of panicle development and rice genotype

Summary Neck nodes of eight rice genotypes were inoculated with a virulent isolate of the blast pathogen at four slightly different, increasingly older stages of panicle development shortly after flowering. Resistance to infection as well as resistance to growth of the pathogen after infection was assessed. Significant differences between genotypes were found for both components of resistance. Resistance to growth of the pathogen sharply increased with aging of the neck node as was indicated by a large reduction of the length of the lesions on the culm, but resistance to infection did not change much. The lesion length was closely related to yield loss. A small delay in time of infection can lead to a large decrease in yield reduction. Meaningful comparison of partial resistance to neck blast between genotypes therefore requires infection at an identical stage of panicle development. In the field, where panicles are in different stages of development, selection of genotypes that do show the symptoms of neck blast together with relatively little yield loss in infected panicles is recommended.     

Marker assisted polycross breeding to increase diversity and yield in perennial ryegrass (Lolium perenne L.)

Summary In this study, the application of molecular markers to optimise genetic diversity in a polycross breeding program of perennial ryegrass (Lolium perenne L.) was evaluated. The genetic diversity among 98 potential parental plants from three maturity groups (early, intermediate and late flowering) was investigated using amplified fragment length polymorphism (AFLP) markers. For each maturity group, two polycrosses of six parental plants with contrasting levels of genetic diversity were composed. Average genetic diversity among parents selected for narrow polycrosses was 36% lower than among parents selected for wide polycrosses. Diversity within first generation synthetic progenies (Syn1) was proportional to the diversity within the respective parental polycrosses. However, differences were less pronounced with Syn1 progenies from narrow polycrosses showing 16% reduced diversity when compared to Syn1 progenies from wide polycrosses. Multivariate analyses allowed for a clear separation of the six Syn1 progenies based on AFLP markers and demonstrated their genetic distinctness. Evaluation of dry matter yield, date of ear emergence and stem length of Syn1 and Syn2 progenies showed progenies from wide polycrosses to be constantly higher yielding when compared to progenies from narrow polycrosses. On the other hand, there was no significant difference in variability for the two morphological traits between progenies of narrow- and wide polycrosses. The results presented here provide evidence for an efficient application of molecular markers to select genetically diverse polycross parents which resulted in an average yield increase of 3.8%.     

Construction of chromosomal segment substitution lines and genetic dissection of introgressed segments associated with yield determination in the parents of a super‐hybrid rice

Heterosis is a phenomenon whereby hybrids of inbred lines produce favourable phenotypes that exceed those of their parents. Traits of interest are higher yield and stronger stress tolerance. The two‐line super‐hybrid rice ‘Liangyoupei9’ (LYP9) shows superiority to both its elite inbred line ‘93‐11’ and ‘Pei'ai64s’ (‘PA64s’) parents and conventional hybrids. However, the genetic basis of its hybrid vigour, especially yield determination, remains elusive. In the present study, a set of 156 chromosome segment substitution lines (CSSLs) carrying overlapping segments from ‘PA64s’ in a genetic background of ‘93‐11’ were constructed and planted in six environments. Three major agronomic traits, viz. panicle length (PL), heading date (HD) and plant height (PH), and five yield‐related traits, viz. grain weight per panicle (GWP), number of grains per panicle (GPP), 1000‐grain weight (TGW), seed set (SS) and number of panicles of per plant (PPP), were evaluated over 3 years. Quantitative trait loci (QTL) analysis was conducted using a likelihood ratio test based on stepwise regression. Forty‐six putative QTL distributed on 11 chromosomes were detected in more than one year. Remarkably, GWP of four CSSLs carrying positive yield QTL outperformed the recurrent parent ‘93‐11’ by more than 15%, in at least two environments. These results indicate that CSSLs are effective in identifying yield‐associated traits, and lines harbouring such QTL will be rich in resources for future molecular breeding programmes.     

一种水肥气高效耦合灌溉系统的设计与试验研究

本研究旨在解决传统灌溉农业的“水氧矛盾”和根系的“向水追氧”两大农业难题,应用现代水肥耦合和增氧灌溉技术,设计了一种水肥气高效耦合灌溉系统。通过应用灌溉系统对水稻、黄瓜等作物的栽培试验证明：相比于常规灌溉方式,水、肥、气耦合灌溉能促进作物根系生长和提高根系活力,使其能最大限度地从土壤中吸收水分和养分,进一步挖掘和提高作物自身生产力,提高水肥利用效率,增产提质,同时也为从根源上缓解农业面源污染提供一种新途径。     

不同白三叶品种在江西低丘红壤地上的适应性研究

本研究通过对６个白三叶品种的适应性观察，认为在江西低丘红壤地上以克利卡诺瓦白三叶表现最好，越夏抗旱力强，青草产量高。种子生产性能以拉丁鲁白三叶最好。海弗白王叶和新西兰白三叶适应性较差，表现不良。