JOURNAL OF PLANT GENETIC RESEARCH
Year:2018 | Volume:5 | Issue:1|Papers Count:7

Selection based on proper selection indices can be one of the most effective methods for indirect selection of yield and yield components, simultaneously. In order to determination of selection index for improvement of maize yield, 60 single cross maize hybrids were planted in two separate experiments (drought stress and normal conditions) based on randomized complete block design (RCBD) with three replications in Torogh agricultural station of Khorasan Razavi agricultural and natural resources research and education center, Mashad, Iran in 2013-2014. Morphological and phenological traits, yield and yield components were recorded. Selection indices were calculated based on results of stepwise regression considering to phenotypc, genotypic and economic values. Based on stepwise regression results in normal condition, physiological maturity, plant height, kernel depth, kernel no. /row and tassel length totally could explain 60. 68 percent of gain yield variation, then these traits were used to calculate selection index. In drought stress condition, kernel no. /row, plant height, ear height, 1000 kernel weight, ear length and leaves no. above ear could explain 63. 77 percent of grain yield variation that these traits were used to calculate of selection index. We used 5 optimum selection indices (smith-hazel) and one basic selection index as Pesk-Baker to screen the maize genotypes. The results showed that the relative efficiency of selection index based on yield and expected genetic gain for all of measured traits in selection index 2 was higher than others in both normal and drought stress conditions. Based on grain yield and selection indices, 20 percent of the best genotypes were selected by each selection indices. Based on derived results in normal condition, genotype no. 60 (ksc704 commercial hybrid) were selected by all of selection indices as the best genotype, but in drought stress condition, different genotypes were selected by different selection indices like genotypes 16 (ME77006/1×K1263/1), 22 (ME77006/1×K1263/1) and 34 (ME78005/2× A679), that these genotypes at least were selected by 2 or 3 selection indices.

In any breeding program, knowledge of the nature of gene action involved in the inheritance of traits is a basic requirement. In this research, diallel crosses progenies of six coriander landrace were evaluated in F1 and F2 generations. The genotypes were evaluated in different irrigation conditions in three separate experiments, in which each experiment was conducted in a randomized complete block design with three replications during the growing season of 2016. Results of genetic variance analyses revealed significant mean squares of general and specific combining ability for all traits, indicating the importance of additive and non-additive genetic effects for these traits. Additive gene actions played a more important role in controlling of plant height, leaf number, branch number and biological yield, whereas the role of non-additive gene actions was more conspicuous than those of additive gene actions in controlling of harvest index and fruit yield. Therefore, providing superior hybrids using breeding methods based on progeny test will be effective to improve these traits. Also, among selected parents, P4 parent in normal irrigation and moderate water stress and P6 parent in sever water stress were the best parents for crosses in the development of high-yield varieties in coriander.

One of the main objectives of plant breeding is defining the relationship between genotype and phenotype. Nowadays, molecular markers provide powerful tools to evaluate this relationship for plant breeders. In this study, genetic diversity of 112 rice lines was evaluated by 20 pairs of SSR markers which linked to drought tolerant alleles. Totally, 77 polymorphic alleles with mean of 3. 85 alleles per primer pairs were amplified. The minimum number of alleles was belonged to RM28199 and RM212 markers with 2 alleles, and the maximum number of alleles was belonged to RM72 marker with 6 alleles. The range of PIC for the examined markers was 0. 30 to 0. 72 and the mean of PIC was 0. 58. The maximum amount of PIC was belonged to RM85 and RM20A markers and the minimum of PIC was belonged to RM28099 marker. Considering the gene diversity coeficient, RM28099 and RM 85 markers had minimum (0. 33) and maximum (0. 76) diversity, respectively. The stepwise regression analysis of the microsatellite data and morphologic traits identified 62 and 54 informative alleles for the evaluated traits in flooding and drought conditions, respectivly. Cluster analysis based on molecular data divided the genotypes into 7 groups. Considering the appropriate distribution of amplified DNA by the studied markers in this study, markers that have high separation power and high association with important agronomic traits in drought stress condition (if further experiments confirmed them), could be employed in plant breeding programs of drought stress.

Chrysanthemum (Chrysanthemum morifolium) is one of the most important ornamental plants which plays a significant role in the development of gardening industry in the world. The knowledge of genetic diversity is one of the prerequisite criteria for Chrysanthemum breeding with important economic goals. Molecular markers have a significant share in elucidation of inter and intra species genetic diversity. To this end, genetic diversity of a number of Iranian cultivars was molecularly investigated by sequencing a part of rDNA, using ITS4 and ITS5 primers. Genetic distance between Chrysanthemum cultivars ranged from 0. 05 to 10. 15, demonstrating the power of ITS region in revealing the genetic diversity among cultivars of morifolium, suggesting Iranian cultivars have been genetically improved from morifolium species. Genetic diversity assessment of Iranian Chrysanthemum cultivars demonstrated that presumably inter, intra species or even inter population hybridization may have been involved in creating enormous genetic diversity among Chrysanthemum cultivars.

Melon is an important crop cultivated in moderate climate regions of the world. One of the most important diseases of this plant is vascular wilt caused by Fusarium oxysporum f. sp. melonis (Fom). Infection of farm by this pathogen can result in huge damage around the world. Development of resistant varieties is the most effective method for disease control. Four races of 0, 1, 2 and 1, 2 have been reported for this pathogen and 1 is more versatile and dangerous races especially in the north half of Iran. Garmak, as an important variety in Isfahan province, is susceptible to race 1. Single dominant gene of Fom-2 induces resistance against race 0 and 1. In this research, the resistance gene was transferred from Isabelle into Garmak using SNP marker assisted back-crossing. The screening of plants in BC1, BC2, and BC3 generations was carried out using artificial inoculation. This gene was sequenced partially in parental genotypes and resistant and susceptible alleles were discriminated. In order to verify the resistant plants survived after artificial inoculation in BC3, plants were genotyped using the SNP marker and HRM method. This method distinctly separated three genotypes (RR, Rr and rr) from each other. The resistance of most plants was verified by molecular method. However, among resistant genotypes identified by artificial inoculation method, there were some susceptible plants identified by molecular method, indicating the more confidence of molecular method in genotyping of plants. With selfing of BC3 resistant plants and selection of homozygote resistant plants, it is possible to develop resistant Garmak variety.

The chloroplastic DNA of 64 accessions of apple (Malus spp. ) (54 Iranian genotypes, five commercial cultivars and five rootstocks) were analyzed to reveal their haplotypes by using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. Approximately 4320 bp of the chloroplast genome was analyzed, by using two chloroplast universal primer pairs and two restriction enzymes (EcoRI and MseI). All the mutations detected were insertion-deletions been in the range between 10-40 bp. The combination of all the mutations resulted to six haplotypes (H1, H2, H3, H4, H5 and H6) in the studied apple accessions. It was defined that the Iranian apple rootstock 'Gami-Almasi' had a specific haplotype form all the other studied accessions. It was approved that cpDNA diversity data can be considered for phylogenetic studies in this plant and the polymorphism determined in cytoplasmic genome by PCR-RFLP method can help to understand the maternal inheritance in apple.

Collection and conservation of germplasm, particularly for landraces of important agronomically species and organizing their information, cause to continuity of their usefulness and reduce the risk of their genetic erosion. In this experiment, 10 Iranian wheat landraces along with the Chinese Spring cultivar, as control, were used to assess inter and intra populations variation by using ISSR molecular markers and morphological traits. Evaluation of populations in terms of height, spike length, awn length, number of spike nodes, number of grains per spike, flag leaf length and grain weight showed that there were considerable variation among landraces. Also, in some landraces like KhorramAbad and Ardabil, intra population diversity for some of these traits, such as plant height and length of awn, was obvious. Evaluation of the landraces for ISSR markers showed that among 99 scored bands, 78 bands were polymorphic. Percent of polymorphism with mean of 81. 88 % was varied from 53. 33 for primer of ISSR-4 to 100% for primers of ISSR-9, ISSR-14, ISSR-5 and ISSR-7. Average PIC of the landraces was estimated 3. 0. Results of this study showed that there was considerable intra population diversity for the ISSR markers in landraces of KhorramAbad, Maragheh and Torbat-e-Heydarieh however, a little diversity for Khoy, Ahwaz, Isfahan, Mashad, Urmia, Shiraz and Ardabil was observed. Results of this study showed that there is inter and intra genetic diversity within Iranian landraces of wheat with different levels and these landraces can be used as basic population for extraction of pure lines.