Effect of environment and genotype on bread-making quality of spring-sown spring wheat cultivars in China

Improvement of end-use quality in bread wheat depends on a thorough understanding of current wheat quality and the influences of genotype (G), environment (E), and genotype by environment interaction (G × E) on quality traits. Thirty-nine spring-sown spring wheat (SSSW) cultivars and advanced lines from China were grown in four agro-ecological zones comprising seven locations during the 1998 and 1999 cropping seasons. Data on 12 major bread-making quality traits were used to investigate the effect of G, E, and G × E on these traits. Wide range variability for protein quantity and quality, starch quality parameters and milling quality in Chinese SSSW was observed. Genotype and environment were found to significantly influence all quality parameters as major effects. Kernel hardness, flour yield, Zeleny sedimentation value and mixograph properties were mainly influenced by the genetic variance components, while thousand kernel weight, test weight, and falling number were mostly influenced by the environmental variance components. Genotype, environment, and their interaction had important effects on test weight, mixing development time and RVA parameters. Cultivars originating from Zone VI (northeast) generally expressed high kernel hardness, good starch quality, but poor milling and medium to weak mixograph performance; those from Zone VII (north) medium to good gluten and starch quality, but low milling quality; those from Zone VIII (central northwest) medium milling and starch quality, and medium to strong mixograph performance; those from Zone IX (western/southwestern Qinghai-Tibetan Plateau) medium milling quality, but poor gluten strength and starch parameters; and those from Zone X (northwest) high milling quality, strong mixograph properties, but low protein content. Samples from Harbin are characterized by good gluten and starch quality, but medium to poor milling quality; those from Hongxinglong by strong mixograph properties, medium to high milling quality, but medium to poor starch quality and medium to low protein content; those from Hohhot by good gluten but poor milling quality; those from Linhe by weak gluten quality, medium to poor milling quality; those from Lanzhou by poor bread-making and starch quality; those from Yongning by acceptable bread-making and starch quality and good milling quality; and those from Urumqi by good milling quality, medium gluten quality and good starch pasting parameters. Our findings suggest that Chinese SSSW quality could be greatly enhanced through genetic improvement for targeted well-characterized production environments.     

Photomorphogenic mutants of tomato

Summary Two cloned cassava genes (pCAS6, pHNL) and a barley gene (pBLT63) which is highly conserved in higher plants, were evaluated as potential multilocus probes for RFLP analysis of phylogenetic relationships of species within the genus Manihot. For M. rubricaulis, M. chlorosticta and M. esculenta subsp. flabellifolia dendrograms based on 13 probe-restriction enzyme combinations show very little variation between accessions of the same species. A close relationship is demonstrated between the Mexican species M. chlorosticta and the M. esculenta subsp. flabellifolia accessions, which does not support the classification of flabellifolia as a true South American wild species.     

Progenies of allotriploids of Oriental × Asiatic lilies (Lilium) examined by GISH analysis

With the aim of utilizing allotriploid (2n = 3x = 36) lily hybrids (Lilium) in introgression breeding, different types of crosses were made. First, using diploid Asiatic lilies (2n = 2x = 24), reciprocal crosses (3x − 2x and 2x − 3x) were made with allotriploid hybrids (AOA) obtained by backcrosses of F₁ Oriental × Asiatic hybrids (OA) to Asiatic cultivars (A). Secondly, the AOA allotriploids were crossed with allotetraploid (OAOA, 2n = 4x = 48), in 3x − 4x combination. Finally, the AOA allotriploids where crossed to 2n gamete producer F₁ OA hybrids (3x − 2x (2n)). Two types of triploids were used as parents in the different types of crosses, derived from: (a) mitotic polyploidization and (b) sexual polyploidization. Ploidy level of the progeny was determined by estimating the DNA values through flowcytometry as well as chromosome counting. The aneuploid progeny plants from 3x − 2x and reciprocal crosses had approximate diploid levels and in 3x − 4x crosses and 3x − 2x (2n) the progeny had approximate tetraploid levels. Balanced euploid gametes (x, 2x and 3x) were formed in the AOA genotypes. Recombinant chromosomes were found in the progenies of all crosses, except in the case of 2x − 3x crosses through genomic in situ hybridization (GISH) analyses. Recombinant chromosomes occurred in the F₁ OA hybrid when the triploid AOA hybrid was derived through sexual polyploidization, but not through mitotic polyploidization with two exceptions. Those recombinant chromosomes were transmitted to the progenies in variable frequencies.     

如何在花卉产销中增加产品附加值

超市的出路现在许多人都在满怀希望地关注着花卉零售连锁产业的发展,这个市场越来越大,参与的人们都希望能分得一杯羹。但是英国的经营模式告诉我们,在花卉贸易中,连锁经营中供应商的选择相当重要。     

Breeding for resistance to coffee berry disease caused by Colletrotrichum coffeanumNoack (Sensu Hindorf) in Coffea arabica L. I. Methods of preselection for resistance

Summary Two methods of preselection for resistance to coffee berry disease, by artificial inoculation of young coffee seedlings, have been developed recently at the Coffee Research Station in Kenya. The efficiency of these methods has been investigated in a series of experiments by comparing the results of the preselection tests with mature plant resistance, as indicated by visual field scores and artificial inoculation of berries and bud leaves of mature trees and including a large number of varieties and cultivars of Coffea arabica. The preselection test, by which the hypocotyl stems of 6-week old seedlings are inoculated with a spore suspension of the pathogen, proved to be more reliable than the second preselection test with shoot-tips of 10-month old plants. Correlation coefficients between the preselection test and mature plant resistance were resp. r=0.73–0.80 for the first test against r=0.60 for the latter.     

Causal relationships between inbreeding, seed characteristics and plant performance in leek (Allium porrum L.)

Leek (Allium porrum L.) is an important outdoor vegetable in West Europe, where it is cultivated on about 30,000 ha. Most commercial cultivars of leek are open pollinated. One of the major problems with the crop is poor uniformity. Leek is an outbreeding species with up to 20% self-fertilisation. Much of the variation of open pollinated cultivars is explained by the strong sensitivity to in breeding depression after selfing. In this study we attempt to analyse in a systematic way the relationship between degree of selfing and agricultural performance in leek. The results obtained confirm a negative correlation between selfing and somea gricultural aspects important for vigour such as seedling emergence, plant growth and plant fresh yield. Also negative correlations between degree of selfing and seed individual weight and between selfing and seed individual size were found. The negative relationship between inbreeding and plant weight at harvest is further confirmed in an experiment in which the origin (cross-pollination orself-pollination) of each individual offspring plant analysed was determined using AFLP-markers. Finally, the correlation between chlorophyll deficiency genes and the loss of vigour that follows selfing was investigated. The results obtained demonstrate a significant decrease of pigment content in two generations of selfing. This revised version was published online in July 2006 with corrections to the Cover Date.     

Factors affecting seed yield in white clover

Summary Eighteen clones of white clover chosen at random were examined for their seed setting possibilities. Large differences in the size of the inflorescence and the rate of fertilization were found among the clones, so that breeding strains of white clover with better seed-setting seems possible. The number of ovules per floret seemed not very variable.     

Role of the genes Md-ACO1 and Md-ACS1 in ethylene production and shelf life of apple (Malus domestica Borkh)

Shelf life determines the economic life time of mature apples, which can be either freshly harvested or stored. Good shelf life is highly associated with a slow decrease of fruit firmness at room temperature. Apple is a climacteric fruit, in which loss of firmness seems to be physiologically related to ethylene. Ethylenes biosynthetic pathway is controlled by two large gene families coding for 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxydase (ACO).In this study, one ACS and one ACO gene were examined for their effect on ethylene production and shelf life in apple using gene specific molecular marker, and have also been positioned on a molecular marker linkage map. The ACO marker was developed in this research and mapped on linkage group (LG) 10 of the crosses Prima × Fiesta and Fuji × Mondial Gala, within the 5% border of a previously identified fruit firmness QTL [Theor Appl Genet 100 (2000) 1074]. We denoted this locus as Md-ACO1. In addition, we mapped the previously developed Md-ACS1 marker [Theor Appl Genet 101 (2000) 742] on LG15.Studies on the cross Fuji × Braeburn revealed that Md-ACS1 and Md-ACO1 independently affect the internal ethylene concentration (IEC) as well as shelf life of apple, Md-ACS1 having the strongest effect. Descendants homozygous for Md-ACS1-2 and Md-ACO1-1 showed to have the lowest ethylene production as well as superior shelf-life. These two genes are candidates to be included in marker assisted breeding.     

Single nucleotide polymorphism discovery and linkage mapping of lipoxygenase-2 gene (Lx 2) in soybean

Lipoxygenase-2 (Lx ₂) in soybean seed is mainly responsible for generation of grassy-beany and bitter flavors. Genetic elimination of this flavor can be accelerated by the development of single nucleotide polymorphism (SNP) markers linked to Lx ₂. A frame map based on simple sequence repeat (SSR) markers was constructed first using a recombinant inbred line (RIL) population of Pureunkong × Jinpumkong 2. Sixty-five SSR markers were incorporated into 13 linkage groups (LGs) spanning a total of 737 cM. Among five primer pairs designed from the Lx ₂ gene sequence, one produced an amplicon with sequence variations between Pureunkong and Jinpumkong 2. Three SNPs, T/C, G/A and C/A, were identified at 251,367 and 420 bp, respectively, in the intron region of the 804 bp amplified product. Using single base chain extension based on the capture probe sequence in the 5' region of the T/C SNP, the 90 RILs were genotyped for each allele of Lx ₂. The allelic segregation for the SNP linked toLx ₂ was in accordance with the expected ratio of 1:1 in the RIL population. Based on the results of linkage analysis between Lx ₂ and the SSR markers, Lx ₂ was found to be positioned on one end of LG F in the frame map, flanked by the SSR markers Satt522 and Sat074. This study demonstrates that SNP markers closely linked to Lx ₂can be developed to facilitate marker-assisted selection and fine mapping of the region around this locus. This revised version was published online in July 2006 with corrections to the Cover Date.