Authors:E. Idehen, O. Kehinde, X. Wang, and A. Popoola
‘Egusi’ melon Citrullus lanatus (Thunb.) Matsum. & Nakai is an important vegetable crop in Nigeria, grown for its edible seeds and oils. The diverse areas in which the crop is cultivated make it a rich source of genetic resources for the species. To explore its diversity, 50 accessions of ‘egusi’ melon were collected from different agro-ecological parts of Nigeria and were evaluated using 25 simple sequence repeat (SSR) markers. A total of 49 bands were scored, of which 42 were polymorphic, accounting for 93.60% of the polymorphic loci. The PIC value ranged from 0.36–0.80. UPGMA cluster analysis revealed five distinct groups for SSR. PCA analysis revealed the distinction of the accessions NG/OE/MAR/09/014, NG/TO/APR/09/027 and A8. Based on the results of this study, SSR markers appear to be particularly useful for the estimation of genetic similarity among diverse accessions of melon.
The growing interest in emmer cultivation has no doubt been stimulated by the increasing demand for traditional foods with an image of naturalness, especially on the organic market. The new economic situation could stimulate the breeding and production of emmer as the source of an especially valuable foodstuff. It is the task of breeders to produce emmer varieties that can survive even the hardest winter occurring in the targeted cultivation area without serious damage. The best sources to improve the winter hardiness are probably the emmer genetic resources stored in genebanks. Unfortunately no public data are available on the frost tolerance and winter hardiness of the various genebank accessions. In the present research the frost tolerance and winter hardiness of 10 winter emmer genebank accessions were studied under nursery and phytotronic conditions. The results suggest that the majority of the populations studied are frost-sensitive, and only few landraces have an acceptable level of winter hardiness and frost resistance.
Authors:K. Niwa, H. Suzuki, T. Tominaga, S. Nasim, R. Anwar, M. Ogawa, and Y. Furuta
SDS-PAGE was used to determine the variation in high molecular weight glutenin subunits (HMW-GS) alleles present in 170 landraces of common wheat from Sindh, Balochistan and NWFP in Pakistan. Three alleles for
, six alleles for
and four alleles for
were detected. These included three new alleles, namely
, which had not previously been found in landraces of Pakistani wheat. Furthermore,
, which are considered to be endemic alleles in Pakistan and Afghanistan, were both detected from Balochistan. Twenty genotypes were identified based on combinations of alleles at the three
loci. The present study showed that Pakistani landraces of common wheat have maintained a broad diversity of HMW-GS alleles, and that they may serve as genetic resources to improve wheat varieties adapted to Pakistani climatic and edaphic conditions.
Authors:S. Figlan, T.A. Baloyi, T. Hlongoane, T.G. Terefe, H. Shimelis, and T.J. Tsilo
Phenotypic and genotypic evaluation of wheat genetic resources and development of segregating populations are pre-requisites for identifying rust resistance genes. The objectives of this study were to assess adult plant resistance (APR) of selected wheat genotypes to leaf rust and stem rust and to develop segregating populations for resistance breeding. Eight selected Kenyan cultivars with known resistance to stem rust, together with local checks were evaluated for leaf rust and stem rust resistance at seedling stage and also across several environments. Selected diagnostic markers were used to determine the presence of known genes. All eight cultivars were crossed with local checks using a bi-parental mating design. Seedling tests revealed that parents exhibited differential infection types against wheat rust races. Cultivars Paka and Popo consistently showed resistant infection types at seedling stage, while Gem, Romany, Pasa, Fahari, Kudu, Ngiri and Kariega varied for resistant and susceptible infection types depending on the pathogen race used. The control cultivars Morocco and McNair consistently showed susceptible infection types as expected. In the field, all cultivars except for Morocco showed moderate to high levels of resistance, indicating the presence of effective resistance genes. Using diagnostic markers, presence of Lr34 was confirmed in Gem, Fahari, Kudu, Ngiri and Kariega, while Sr2 was present in Gem, Romany, Paka and Kudu. Seedling resistance gene, Sr35, was only detected in cultivar Popo. Overall, the study developed 909 F6:8 recombinant inbred lines (RILs) as part of the nested mating design and are useful genetic resources for further studies and for mapping wheat rust resistance genes.
Authors:M. Megyeri, P. Mikó, I. Molnár, and G. Kovács
Cultivated einkorn (Triticum monococcum L. ssp. monococcum) is an excellent source of resistance against several wheat diseases and quality parameters. Semi-dwarf einkorn lines with good crossability were identified in order to produce Triticum turgidum × T. monococcum synthetic amphiploids. Two combinations were used to develop the amphiploids: durum × einkorn and emmer × einkorn.After the genome duplication of F1 seeds, highly fertile amphiploids were developed. The AuBAm genome structure of the progenies was confirmed by genomic in situ hybridization (GISH).Lines derived from durum × einkorn and emmer × einkorn crosses were studied for agronomic performance, disease resistance and genetic variability. Both amphiploid combinations showed excellent resistance against certain wheat diseases (leaf rust, powdery mildew), but not against fusarium. The durum-based synthetic amphiploid lines showed a higher level of phenotypic diversity. The newly produced T. turgidum × T. monococcum synthetic hexaploids are promising genetic resources for wheat breeding. Selected durum × einkorn lines are currently used in bread wheat improvement to transfer the useful properties of einkorn into cultivated hexaploid wheat via ‘bridge-crossing’.
Authors:S. Keskin Şan, Ö. Özbek, V. Eser, and B. Göçmen Taşkin
The objective of this study is the analysis of polymorphism in seed endosperm proteins (gliadins and glutenins) of Turkish cultivated einkorn wheat [Triticum monococcum ssp. monococcum] landraces. The genetic diversity of high-molecular-weight (HMW) glutenin subunits and the gliadin proteins in 10 landrace populations of cultivated einkorn wheat, originating from Turkey, was investigated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and ammonium lactic acid polyacrylamide gel electrophoresis (A-PAGE), respectively. For glutenins, the mean number of alleles, the mean number of effective alleles, the mean value of genetic diversity and the mean value of average genetic diversity were detected as 3.50, 2.98, 0.65 and 0.28, respectively. The genetic differentiation was 0.57, while gene flow was 0.19 between populations. For gliadins, the mean number of alleles, the mean number of effective alleles, the mean value of total genetic diversity and the genetic diversity within population were detected as 2.00, 1.21, 0.17 and 0.15, respectively. The genetic differentiation was 0.08, whereas gene flow was 6.15 between populations. STRUCTURE is a software package program for population genetic analysis, was used to infer population structures of landraces populations. The optimum value for K was obtained as 10. Considering the high number of proteins and genetic variation, and increased interest in organic products, the farming of einkorn wheat should be supported and conservation of germplasm in landraces should be maintained as important genetic resources. The landraces germplasm should be conserved for future crop improvement processes.
Avena spp. were artificially inoculated with Fusarium culmorum Sacc. (FC) and F. graminearum Schwabe (FG) causing Fusarium head blight (FHB). This disease is often accompanied by the accumulation of Fusarium mycotoxins mainly deoxynivalenol (DON) in grains. The contaminated grains with this mycotoxin are toxic to their consumers. Genotypes Avena spp. with low DON accumulation in grains can be used as genetic resources suitable for the formation of new resistant varieties of oats against FHB caused by fungi FC and FG. The aim was to find out and to compare the potential for mycotoxin accumulation in grains between genotypes of Avena spp. after artificial inoculation panicles by FC and FG using three spray methods and identify genotypes of Avena (A. abyssinica, A. byzantina, A. canariensis, A. fatua, A. ludoviciana, A. nuda, A. sativa, A. sterilis, A. strigosa) with low toxin accumulation in whole grain. The average accumulations of DON in the grains of Avena spp. gradually increased from the spray inoculation (0.68 mg · kg−1), spray + polyethylene (PE) bag cover 24 hrs (2.75 mg · kg−1) and spray + PE bag/48 hrs. (9.46 mg · kg−1) methods. We found out that after application of each used method, the high DON accumulation in grains was found in A. canariensis, and low DON levels were found in A. byzantine and A. sterilis.
Authors:M. Barati, M.M. Majidi, A. Mirlohi, M. Safari, F. Mostafavi, and Z. Karami
The vast genetic resources of wild barley (Hordeum vulgare ssp. spontaneum, hereafter WB) may hold unique assets for improving barley (H. vulgare ssp. vulgare) cultivars for drought stress. To evaluate genetic potential and characterization of variation among a diverse collection of barley and WB genotypes, mostly originated from Iran, a field experiment was performed under three moisture environments (control, mild and intense drought stress) during two years (2012–2014). Considerable variation was observed among the wild and cultivated genotypes for drought tolerance and agronomic traits. Principal component analysis (PCA) grouped genotypes studied into three groups (WB, two-row barley and sixrow barley groups). However, Iranian and foreign WB genotypes were not completely separated, showing a high variation within both gene pools. The high significance of genotype by environment interaction, confirms importance of using accurate target environments for drought stress breeding. A number of WB genotypes with the highest values of the number of tillers, number of seed per spike, seed weight, grain yield and yield stability index under stressed environments were identified as superior genotypes. Most of these genotypes originate from Iran, highlighting the importance of this germplasm in barley breeding.
Authors:Salih Salihu, Heinrich Grausgruber, and Peter Ruckenbauer
In the province of Kosovo there exists no local wheat breeding programme; cultivars grown were originally developed and registered in former Yugoslavia and other neighbouring countries. Within the general attempt to reconstruct the agriculture of Kosovo a three-year study was undertaken to establish winter wheat genotypes adapted to Kosovan growing conditions. Seventy-seven international winter wheat cultivars and/or breeding lines were tested for their agronomic and quality performance in 2000; forty-nine selected genotypes of the nursery were further tested in 2001 and 2002. The multivariate dataset included six yield-and twenty-two quality-related parameters which were subjected to principal component analysis and subsequently to cluster analysis. The 49 genotypes were differentiated into six groups. Two groups which included almost exclusively Central and Eastern European cultivars and breeding lines, respectively, turned out to be best adapted to the prevalent conditions. These genotypes revealed high agronomic and high quality performances, and could, therefore, serve as valuable wheat genetic resources for the buildup of a local winter wheat breeding programme in the future.
Authors:L. Brbaklić, D. Trkulja, A. Kondić-Špika, S. Mikić, M. Tomičić, and B. Kobiljski
The microsatellites, as one of the most robust markers for identification of wheat varieties, were used for assessment of genetic diversity and population structure to promote effective use of genetic resources. In this study, the set of 284 wheat varieties were genotyped using 30 microsatellite markers. The chosen SSR markers were located among almost all linkage groups and covered all three genomes. The genotypes used originate from 24 different breeding centers worldwide and are included in an extensive core collection of the Institute of Field and Vegetable Crops in Novi Sad, Serbia. The total number of detected alleles was 349 at all analyzed loci. The average number of detected allelic variant per locus was 11.5. The mean value of polymorphic information content was 0.68. According to the probability of data obtained by program Structure, the results have shown presence of 6 subpopulations within the studied set of genotypes. The population structure positively correlated to some extent with geographic origin. The available pedigree data were included for additional explanation of population structure. The results of this study should provide valuable information for future association studies using the diverse wheat breeding material.