NrDNA internal transcribed spacer revealed molecular diversity in strains of red seaweed <Emphasis Type="Italic">Porphyra yezoensis</Emphasis> and genetic insights for commercial breeding

Unraveling the cryptic genetic diversity and selective breeding network in various Porphyra strains is of significance for conservation and utilization of economically important nori crops, for both current and future needs. Here, we used nuclear ribosomal spacer (ITS1) region to investigate the genetic variation and intra-specific relatedness of 59 Porphyra yezoensis Ueda specimens worldwide using phylogenetic and parsimony genealogical approaches. 23 nrDNA ITS1 genotypes were revealed and clustering analysis grouped them into two distinct clades. High genetic diversity was detected in wild P. yezoensis strains from Miyagi and Hokkaido Prefectures in Japan, while the cultivated strains from China and South Korea exhibited relatively higher genetic diversity likewise, which provided crucial genetic insights for future commercial breeding of P. yezoensis on a global scale. In addition, phylogenetic study has revealed the genetic relationship of strains with unknown parentage to those with known parentage, and also ITS1 sequence pattern could be correlated with the geographic origin of P. yezoensis specimens. All these pedigree information generated from this research can be used to select parents for inter-specific or intra-specific selective breeding and cross breeding to maximize the preservation of stock resource and sustainable development of nori industry.     

Chemical Manipulation of Reproductive Efficiency of Chickpea (Cicer arietinnum L.) by Triadimefon in Relation to Changes in Ethylene

Reproductive efficiency was successfully manipulated by the application of different concentrations of triadimefon at pre‐flowering, flowering and post‐flowering stages in chickpea (Cicer arietinum L.). Triadimefon improved the parameters determining reproductive efficiency. Yield was significantly improved due to reductions in flower and pod abscission by the application of triadimefon, which also lowered the ethylene levels in leaves, flowers and pods and delayed senescence. These findings suggest a relationship between ethylene level and reproductive efficiency in chickpea. Further, they indicate that triadimefon can be used for chemical manipulation of the reproductive efficiency of chickpea under field conditions.     

Protein extraction from rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) root for two-dimensional electrophresis

An efficient protein extraction method for two-dimensional gel electrophoresis (2-DE) from plant samples is usually challenging due to the low protein content and high level of interfering compounds. Proteomic analyses of rice (Oryza sativa L.) roots are limited by the lack of an efficient protein extraction method. To establish an effective protocol of protein extraction suitable for 2-DE analysis in rice roots, we evaluated three protein extraction methods (trichloroacetic acid [TCA]/acetone, Mg/NP-40/TCA, and tris-base/acetone). Our results showed that the Mg/NP-40/TCA extraction method had the highest protein yield and is the best resolution of protein separation among the three methods. The TCA/acetone method exhibited clear protein profiles and detected more protein spots with the highest intensity in the region of high Mr (above 45 kDa) than the other methods. However, this method was unable to detect proteins with low-Mr (less than 24.0 kDa). The Tris-base/acetone method showed the poorest resolution of protein separation. Our results suggest that the Mg/NP-40/TCA method was the most effective among the three methods and may provide enhanced proteomic information for rice and other crop roots.     

Different genes can be responsible for crown rot resistance at different developmental stages of wheat and barley

Crown rot, caused by several Fusarium species, is one of the most damaging diseases in wheat and barley. Growing resistant varieties has long been recognised as an integral part in effectively managing the disease. One of the factors hindering the progress of breeding for crown rot resistance is the lack of a reliable and high throughput bioassay that allows rapid and accurate assessment of large numbers of genotypes so that highly susceptible materials can be quickly rejected and potentially resistant lines identified for more focused further assessments. We developed a method which, by growing several inoculated seedlings wrapped in a single piece of moist paper towel, offers significant advantages over all of the existing methods. The new soil-less assay takes only about two weeks, requires very little space, and removes variability associated with the use of soil/potting mixes. Results from the new assay are highly reproducible and agree well with known field performances of different varieties. However, mapping studies conducted using the new soil-less assay did not detect all of the quantitative trait loci found with a soil-based assay. These results show that, although different resistance genes may all contribute to the performance of a variety, caution should be used when comparing results from different assays.     

Genome-wide search for segregation distortion loci associated with the expression of complex traits in Populus tomentosa

Segregation distortion of molecular markers has been reported in a broad range of organisms. It has been detected in an interspecific BC1 Populus pedigree established by controlled crossing between clone “LM50” (Populus tomentosa) and its hybrid clone “TB01” (P. tomentosa×P. bolleana). The study with a total of 150 AFLP markers (approximately 18.9% of the total loci) exhibited significant deviation from the Mendelian ratio (1:1) (p<0.01). Twenty-five percent of the markers were mapped on the pa-rental specific genetic linkage maps of clones “LM50” and “TB01” with a pseudo-test-cross mapping strategy. Twelve linkage groups had markers with skewed segregation ratios, but the major regions were on linkage groups TLG2, TLG4 and TLG6 in the linkage map of clone “LM50”. We also analyzed the association between distorted loci and expression of complex traits with Map-maker/QTL software. A total of 16 putative QTLs affecting 12 traits were identified in the distorted regions on seven linkage groups. Therefore we could detect the distribution of skewed loci along the entire genome and identify the association between quantitative traits and segregation loci via genetic mapping in an interspecific BC1 P. tomentosa family. Furthermore, the genetic nature and pos-sible causes of these segregation distortions for differentiation between female and male parents were also discussed.     

A review of stand basal area growth models

Growth and yield modeling has a long history in forestry. The methods of measuring the growth of stand basal area have evolved from those developed in the U.S.A. and Germany during the last century. Stand basal area modeling has progressed rapidly since the first widely used model was published by the U.S. Forest Service. Over the years, a variety of models have been developed for predicting the growth and yield of uneven/even-aged stands using stand-level approaches. The modeling methodology has not only moved from an empirical approach to a more ecological process-based approach but also accommodated a variety of techniques such as: 1) simultaneous equation methods, 2) difference models, 3) artificial neural network techniques, 4) linear/nonlinear regres-sion models, and 5) matrix models. Empirical models using statistical methods were developed to reproduce accurately and precisely field observations. In contrast, process models have a shorter history, developed originally as research and education tools with the aim of increasing the understanding of cause and effect relationships. Empirical and process models can be married into hybrid mod-els in which the shortcomings of both component approaches can, to some extent, be overcome. Algebraic difference forms of stand basal area models which consist of stand age, stand density and site quality can fully describe stand growth dynamics. This paper reviews the current literature regarding stand basal area models, discusses the basic types of models and their merits and outlines recent progress in modeling growth and dynamics of stand basal area. Future trends involving algebraic difference forms, good fitting variables and model types into stand basal area modeling strategies are discussed.