Effects of Compost Source and Timing of Fertigation Initiation on Growth of Potted Poinsettia

Treatment combinations of four poinsettia (Euphorbia pulcherrima) cultivars, 20 substrates, and three fertigation treatments were evaluated in a completely randomized block design. Poinsettia cultivars included ‘V-14 Glory’, ‘Red Sails’, ‘Lilo Pink’, and ‘Annette Hegg Top White’. The compost substrates were compost:peat:perlite blended (by vol.) at 2:3:3, 1:1:1, and 2:1:1 ratios. Sunshine Mix 1 and Pro Gro 300S were used as controls. Composts tested were those prepared from crab offal, lime and polymer-dewatered biosolids, municipal solid waste (MSW), yard waste, and poultry litter. Fertigation treatments were initiated on the week of potting, delayed one or two week after potting and applied once per week. Controls produced premium quality plants. Composts prepared from poultry litter, yard waste, polymer-dewatered biosolids, crab offal, and MSW produced good quality plants. Plant width in 25 percent compost treatments were greater than those in 50 percent compost treatments. Total number of branches, plant height, canopy diameter, and plant grade on plants treated with fertilizer on the first week were only three percent greater than in treatments where fertilizer application was delayed one or two weeks.     

Immature green citrus fruit detection and counting based on fast normalized cross correlation (FNCC) using natural outdoor colour images

A fast normalized cross correlation (FNCC) based machine vision algorithm was proposed in this study to develop a method for detecting and counting immature green citrus fruit using outdoor colour images toward the development of an early yield mapping system. As a template matching method, FNCC was used to detect potential fruit areas in the image, which was the very basis for subsequent false positive removal. Multiple features, including colour, shape and texture features, were combined in this algorithm to remove false positives. Circular Hough transform (CHT) was used to detect circles from images after background removal based on colour components. After building disks centred in centroids resulted from both FNCC and CHT, the detection results were merged based on the size and Euclidian distance of the intersection areas of the disks from these two methods. Finally, the number of fruit was determined after false positive removal using texture features. For a validation dataset of 59 images, 84.4 % of the fruits were successfully detected, which indicated the potential of the proposed method toward the development of an early yield mapping system.     

Effect of two bounding walls on the rotational motion of a fiber in the simple shear flow

The effect of two bounding walls on the rotational motion of a freely suspended non-Brownian fiber in the simple shear flow at low Reynolds number was investigated numerically using the lattice-Boltzmann method. Data were reported for the fibers with aspect ratios of 8, 10, and 15 under various ratios of wall gap (2h) to fiber length (L). For 2h/L≥3.0, the time-dependent orientation of the fiber is shown to be in quantitative agreement with the Jeffery’s theory for ellipsoids suspended in an unbounded linear shear flow, and the effect of the walls on the rotational period of the fiber is insignificant for all fibers with different aspect ratios. For 1.8≤2h/L<3.0, the results reveal that the walls have different effects on the rotation of fiber. For 2h/L<1.8, the complete periodical motion of the fiber is suppressed. The fiber rotates to nearly aligning with the flow direction, and then ceases to rotate. In this orientation, the walls have a stabilizing effect on the fiber and this effect is more pronounced for the fibers with large aspect ratio. The fiber finally does not orient with the flow direction, but with a small angle with the flow direction, and the angle is an increasing function of the fiber aspect ratio and dependent on the wall gap.     

Genetic dissection of seed vigour under artificial ageing conditions using two joined maize recombinant inbred line populations

Seed vigour plays an important role in agricultural production, and seeds with high sowing quality are necessary for improving agriculture production. In our study, two connected maize recombinant inbred line (RIL) populations derived from Yu82 × Shen137 and Yu537A × Shen137 crosses were evaluated for the mean germination time (MGT) and other related traits under three artificial ageing treatments. We used meta‐analysis to integrate genetic maps and identify quantitative trait loci (QTLs) across the two populations. In total, 74 QTLs and 20 meta‐QTLs (mQTLs) were identified. Four key mQTLs, mQTL2‐2, mQTL5‐4, mQTL6 and mQTL8, which contained initial QTLs with R² values >10% and included 5–9 initial QTLs, may be hot spots of important QTLs for the associated traits. Twenty‐two key candidate genes associated with four seed vigour‐related traits mapped to 14 mQTLs. In particular, the GRMZM2G163749, GRMZM2G122172/GRMZM2G554885/GRMZM2G122871 and GRMZM2G150367 genes mapped within the important mQTL5–4, mQTL6 and mQTL8 regions, respectively. Fine mapping for the genetic regions of these three mQTLs merits further study and could be utilized for marker‐assisted breeding.     

Conversion of the genic male sterility (GMS) system of bell pepper (Capsicum annuum L.) to cytoplasmic male sterility (CMS)

Non‐pungent bell pepper (Capsicum annuum L.) lacks the cytoplasmic male sterility (CMS) nuclear restorer allele, Rf, and CMS cannot be employed in its F₁ hybrid seed production. To demonstrate that the genic male sterility (GMS) system in non‐pungent bell pepper can be converted to the CMS male sterility system, the conversion of GMS to CMS for non‐pungent bell pepper line GC3 was conducted by introgression of S‐type cytoplasm and the Rf allele from tropical pungent donors. After morphological traits were evaluated, two lines from BC₁F₁ containing S‐type cytoplasm and four lines from BC₂F₂ containing Rf allele, phenotypically similar to GC3, were obtained and could be employed as CMS male sterile lines and restorer lines for non‐pungent bell pepper. Four molecular markers potentially linked to traits of interest were also evaluated in BC₁F₁ and BC₁F₂ populations. This is the first time that GMS has been successfully converted to CMS in bell pepper, a significant contribution for bell pepper hybrid seed production.     

Application of PCR technique in diagnosis of small ruminant lentivirus infection in sheep and goats

Detection of small ruminant lentiviruses (SRLVs) in sheep and goats usually relies on serological testing. In this study, we evaluated semi-nested PCR and nested PCR techniques applied as a diagnostic tool for detection of maedi-visna virus (MVV) and caprine arthritis-encephalitis virus (CAEV) in naturally infected sheep and goats, respectively. The examination of 193 ovine and 85 caprine serum samples by the ELISA revealed the presence of specific antibodies in 133 (69%) and 18 (21.2%) animals, respectively. Presence of proviral DNA was manifested in 103 (53.4%) sheep and 12 (14.2%) goats. Despite the relatively lower sensitivity of PCR, the fact of detection of proviral DNA in 19 out of 60 ovine samples and 7 out of 67 caprine samples collected from animals previously negative by ELISA was noteworthy. In conclusion, the data demonstrated that combinations of both ELISA and PCR might afford optimal detection of SRLVs infection.     

Isolation and partial characterization of bovine foamy virus from Polish cattle

The first isolation and partial characterization of bovine foamy virus (BFV), also known as bovine syncytial virus, in Poland is described. This virus was isolated by co-cultivation of peripheral blood leukocytes from infected cattle with permissive Cf2Th cells. The new isolate, called BFV100 was identified using several techniques: electron microscopy, western blotting, PCR and sequencing of a part of the gag and pol/env genes. Based on syncytia induction, antigenic determinants, primer binding sites and sequence analysis, it can be concluded that isolate BFV100 is bovine foamy virus and is related to the known American and German BFV isolates by sequence homology and antigenic relatedness.     

红壤丘陵区不同土地利用方式下的土壤侵蚀特征

首先利用TM遥感图像解译出2000年兴国县土壤侵蚀强度图及土地利用图,在GIS的支持下,通过对2图的叠加分析,来研究典型红壤丘陵区不同土地利用类型上不同土壤侵蚀的分布特征。结果表明,强度侵蚀主要分布在裸地、旱地、草地及园地类型上,中度侵蚀主要分布在疏林地、草地及旱地上,而轻度侵蚀在各种土地利用上均有不同的程度的分布,但主要集中在疏林地上,旱地及草地次之。这说明建造良好的植被条件是防止强度土壤侵蚀发生有效途径。从土壤侵蚀率上来看,裸地、旱地、草地及园地是严重土壤侵蚀集中分布的几种土地利用类型,文章最后从土地合理利用的角度,提出了相应的土地利用建议。     

黄淮海糯玉米区域试验品种品质评价的分析与研究

通过分析2006-2007年黄淮海糯玉米国家区域试验31个参试品种品质评价的基本情况,总结要选育出显著优于或优于对照的糯玉米品种的主攻品质目标是糯性和果皮厚薄;通过分析品质评价鉴定的主要方法、程序和技术,总结科学、客观、公正、准确评价糯玉米品质的经验,并提出改进品质评价的建议。