Application of the pipe model theory to non-destructive estimation of leaf biomass and leaf area of pruned agroforestry trees

The relationship of branch cross sectional area (CS) to leaf biomass (LM) and leaf area (LA) was studied in three agroforestry tree species,Calliandra calothyrsus Maissn.,Erythrina berteroana Urban andErythrina poeppigiana (Walpers) O.F. Cook, to develop a non-destructive method for the estimation of LM and LA for trees managed with periodic pruning. Variation in these relationships was observed according to the bifurcation level and, in theErythrina spp., by clone. All the relationships were linear except the CS-LM relation in small branches ofE. poeppigiana, where it was initially exponential. At main branch level the relationship of CS to LM and LA was linear in all cases but the regression parameter values varied between species and clones, with determination coefficient (R²) 0.88–0.99. It was concluded that the ratio of main branch CS to LM and LA can be used for non-destructive estimation of the latter variables. The method has the additional benefit that the regression parameter value reflects the allocation of dry matter within a tree and, consequently, may give indications about its possible uses in different agroforestry systems.Work carried out at the Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), Turrialba, Costa Rica.     

不同杂交组合对百合杂交亲和性影响的研究

试验采用去雄、套袋、隔离人工授粉方法,得出百合杂交亲和程度与杂交亲本配组的相关性。研究发现:同一杂种系内品种间杂交大都为亲和的,但同时存在杂交不亲和现象。系间杂交基本上是不亲和的,尽管都是系间杂交,但不同杂交组合的杂交亲和程度不一样。俄维农自交和野百合自交可以获得自交果实和自交胚。     

柳树杂交育种研究

通过多年田间试验证明，旱柳×爆竹柳８号、旱柳×旱柳１０号、钻天柳×白皮柳９号在察右前旗表现速生、抗逆性强的特性。     

Cross Breeding of Populus and Its Hybrids for Cold Resistance

Populus tomento a was crossed with P. tremuloidis, P grandiden ata, P. lba × P. grandidentata and P. alba × Ulmus s . ta pumila in order to maintain its rapid growth and high wood quality and improve its resistance to cold. Two methods were used to increase the germination rate from 1.5% to 41.1% and the remaining rate from 1.7% to 44.2%. Forty crossing combinations were conducted and 2 744 hybrid seedlings were obtained. MX. t4 × P grandiden ata (G-1-58), MX3 × P. tremuloidis (T-44-60), MX2 × P. tremuloidis (l-13-87-37) and MX2 × (P. alba × P. grandidentata) were regarded as superior combinations after analysis and selection. Thirty seedlings of these combinations and 11 triploid seedlings identified by counting their chromosomes were selected as super plants.     

Diversity of insecticide resistance mechanisms and spectrum in European populations of the codling moth, Cydia pomonella

Only a few of the registered insecticides against Cydia pomonella L. are still effective in areas where insecticide resistance has emerged in this pest. Resistance mechanisms are multiple, and their lone or cumulative effects in a single population are not completely understood. A detailed estimation of resistance spectrum is still required to define the suitable insecticides to use against a given population. The efficacy of ten insecticides was therefore investigated together with the resistance mechanisms expressed in four laboratory strains and 47 field populations of C. pomonella from five countries. Bioassays were performed using topical applications of diagnostic concentrations on diapausing larvae, and resistance mechanisms were analysed on adults emerging from control insects. All populations exhibited a reduced susceptibility to at least one insecticide when compared with the susceptible laboratory strain. Cross-resistances were observed between azinphos-methyl or phosalone and more recent compounds such as spinosad and thiacloprid. Resistances to azinphos-methyl, diflubenzuron, spinosad, tebufenozide and thiacloprid were significantly correlated with mixed-function oxidase activity, while increased glutathione-S-transferase and reduced non-specific esterase activities were correlated with resistance to azinphos-methyl and emamectin, respectively. Conversely, resistances to azinphos-methyl, tebufenozide and thiacloprid were negatively correlated with increased esterase activity. None of the observed mechanisms explained the loss of susceptibility of populations to chlorpyrifos-ethyl, and no significant correlation was detected between resistance to deltamethrin and the presence of the kdr mutation. The suitability of such non-target instars to monitor insecticide resistance in field populations is discussed.     

Cross-resistance profile of mesosulfuron-methyl-resistant Italian ryegrass in the southern United States

Diclofop-resistant Lolium species (ryegrass) is a major weed problem in wheat production worldwide. This study was conducted to determine the resistance pattern of diclofop-resistant ryegrass accessions from the southern United States to mesosulfuron-methyl, a recently commercialized herbicide for ryegrass control in wheat; to determine the cross-resistance pattern of a Lolium multiflorum Lam. (Italian ryegrass) accession, 03-1, to acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibitors; and to determine the resistance mechanism of Italian ryegrass to mesosulfuron-methyl. Seventeen ryegrass accessions from Arkansas and Louisiana, including standard resistant and susceptible accessions, were used in this experiment. Fourteen of the 17 accessions were more resistant (four- to > 308-fold) to diclofop than the standard susceptible biotype. One accession, 03-1, was resistant to mesosulfuron-methyl as well as to other ALS inhibitor herbicides such as chlorsulfuron, imazamox and sulfometuron. Accession 03-1, however, did not show multiple resistance to the ACCase inhibitor herbicides diclofop, fluazifop, clethodim, sethoxydim and pinoxaden, nor to glyphosate. The in vivo ALS activity of the 03-1 biotype was less affected by mesosulfuron-methyl than the susceptible biotype. This indicates that the resistance mechanism of Italian ryegrass to mesosulfuron-methyl is partly due to an alteration in the target enzyme, ALS. It is concluded that diclofop-resistant ryegrass in the southern United States can be generally controlled by mesosulfuron-methyl. However, mesosulfuron-methyl must be used with caution because not all ryegrass populations are susceptible to it. There is a need for more thorough profiling of ryegrass resistance to herbicides.     

优质鲜食糯玉米杂交种虞珑糯1612的选育与应用

虞珑糯1612是江苏省常熟市农业科学研究所、常熟市农业科技发展有限公司选育的优质鲜食糯玉米单交种,其母本da11和父本wd11y均是自选自交系;该品种食用口感软糯香甜、色泽美观;2018年、2019年参加江苏省糯玉米新品种区域试验、2020年进入江苏省糯玉米新品种生产试验并完成试验程序,2021年4月通过江苏省农作物品种审定委员会审定。     

Optimizing the use of breed types in developing country livestock production systems: a neglected research area

Developing country livestock production systems are diverse and dynamic, and include those where existing indigenous breeds are currently optimal and likely to remain so, those where non‐indigenous breed types are already in common use, and systems that are changing, such as by intensification, where the introduction of new breed types represents significant opportunities. These include opportunities to improve the livelihood of the world's poor, increase food and nutrition security and enhance environmental sustainability. At present, very little research has focused on this issue, such that significant knowledge gaps in relation to breed‐change interventions remain. The purpose of this study is to raise awareness of this issue and suggests strategic research areas to begin filling these knowledge gaps. Such strategic research would include (i) assessing the impact of differing breed types in developing country livestock productions systems, from a range of viewpoints including intrahousehold livelihood benefit, food and nutrition security at different scales, and environmental sustainability; (ii) identification of specific livestock production systems within developing countries, and the type of livestock keepers within these system, that are most likely to benefit from new breed types; and (iii) identification of new breed types as candidates for in‐situ testing within these systems, such as through the use of spatial analysis to identify similar production environments combined with community acceptance studies. Results of these studies would primarily assist stakeholders in agriculture, including both policy makers and livestock keepers, to make informed decisions on the potential use of new breed types.     

无线网在海洋渔业中的应用探讨

当今互联网迅猛发展，各行各业应用互联网进行信息化管理已成必然趋势。但是由于海洋渔业所涉及的面广、点多、点分散等特点，在应用互联网进行信息化管理方面有一定的困难。然而随着无线互联网的出现与普及，海洋渔业也能象其它行业一样越来越多地应用互联网，加快渔业信息化的进程。