scholarly journals GENETIC VARIABILITY AND RELATIONSHIPS AMONG SUGARCANE VARIETIES BASED ON TRAP MARKERS OF STRESS TOLERANCE CANDIDATE GENES AND SOME AGRONOMIC TRAITS

2015 ◽  
Vol 6 (11) ◽  
pp. 545-557
Author(s):  
K. A. Amein ◽  
H. M. El-Aref
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jose Miguel Soriano ◽  
Pasqualina Colasuonno ◽  
Ilaria Marcotuli ◽  
Agata Gadaleta

AbstractThe genetic improvement of durum wheat and enhancement of plant performance often depend on the identification of stable quantitative trait loci (QTL) and closely linked molecular markers. This is essential for better understanding the genetic basis of important agronomic traits and identifying an effective method for improving selection efficiency in breeding programmes. Meta-QTL analysis is a useful approach for dissecting the genetic basis of complex traits, providing broader allelic coverage and higher mapping resolution for the identification of putative molecular markers to be used in marker-assisted selection. In the present study, extensive QTL meta-analysis was conducted on 45 traits of durum wheat, including quality and biotic and abiotic stress-related traits. A total of 368 QTL distributed on all 14 chromosomes of genomes A and B were projected: 171 corresponded to quality-related traits, 127 to abiotic stress and 71 to biotic stress, of which 318 were grouped in 85 meta-QTL (MQTL), 24 remained as single QTL and 26 were not assigned to any MQTL. The number of MQTL per chromosome ranged from 4 in chromosomes 1A and 6A to 9 in chromosome 7B; chromosomes 3A and 7A showed the highest number of individual QTL (4), and chromosome 7B the highest number of undefined QTL (4). The recently published genome sequence of durum wheat was used to search for candidate genes within the MQTL peaks. This work will facilitate cloning and pyramiding of QTL to develop new cultivars with specific quantitative traits and speed up breeding programs.


Sugar Tech ◽  
2010 ◽  
Vol 12 (1) ◽  
pp. 59-63 ◽  
Author(s):  
Priyanka Saxena ◽  
R. P. Srivastava ◽  
M. L. Sharma

Author(s):  
Thien Minh Nguyen ◽  
Tien Thi My Pham

The agronomic values of this population have been evaluated in the field experiments based on their phenotypic performance of agronomic traits, but the genetic variability of this population needs to be evaluated via techniques based on genetic material - DNA. In this study, the genetic variability in the investigated population of 71 hybrids and their parents was evaluated by RAPD technique, using eight selected arbitrarily primers; Genetic parameters and dendrogram expressing the genetic relationships among the investigated population were analyzed by GenALEx 6.1, Popgene 1.31 and NTSYSpc 2.1 softwares. Eight primers were used to generate the amplify products on each individual in the investigated population. From 74 genotypes, a total of 109 fragments were generated, among which, there were 89 polymorphic bands representing 81.65% with an average of 11 polymorphic bands/primer. Genetic similarity coefficient among the investigated population, based on DICE coefficient, ranged from 0.560 (LH05/0822 and PB260) to 0.991 (LH05/0781 and LH05/0841) with an average of 0,796, meaning that the genetic distance among ranged from 0.009 to 0.440 with an average of 0.231. The Shannon index and mean heterozygosity values were 0.328 and 0,176, respectively. This indicated that the progenies of the two investigated crosses possessed a relatively high range of genetic variability. The analysis of molecular variance (AMOVA) showed that genetic variation within population represented 62%, while genetic variation among two different crosses contributes 38% to the total genetic variability. Dendrogram based on DICE’s genetic similarity using UPGMA method showed that the hybrids divide into two major genetic groups (0.75), but the crosses were scattered independently of the hybrid.


2016 ◽  
Vol 7 (1) ◽  
pp. 58
Author(s):  
Enrique Navarro ◽  
Cristina Vega ◽  
Fernando Narváez ◽  
Hugo Córdova

This study was carried out in 1993 to evaluate S2 lines from four maize tropical populations improved by reciprocal recurrent selection. These lines were evaluated under field and laboratory conditions, the latter one to determine physiology quality. The main goal was to measure genetic variability within and among populations for traits such as grain yield, vigor and germination and to select the best lines under field and laboratory conditions. The combined analysis of variance showed great genetic variability among the S2 lines within and among populations for grain yield, days to flower, plant and ear height, among others. The maximum genetic variability was observed on the lines from population 43 and pool 23 for most of the traits, although the latter showed a greater genetic variability for grain yield. Besides, it is important to mention that the above populations included the best genotypes for grain yield, germination and vigor. Taking into account the above mentionel agronomic traits, fifteen lines were selected; 2 belong to population 43* pool 20, 2 from pool 19* pool 23, 8 from population 43, and 3 from pool 23. These results confirm the genetic superiority of the lines from populations 43 and pool 23, so that these populations should be recommended for future genetic improvement by reciprocal recurrent procedures.


2019 ◽  
Author(s):  
Waltram Ravelombola ◽  
Jun Qin ◽  
Ainong Shi ◽  
Fengmin Wang ◽  
Yan Feng ◽  
...  

Abstract Background Soybean [ Glycine max (L.) Merr.] is a legume of great interest worldwide. Enhancing genetic gain for agronomic traits via molecular approaches has been long considered as the main task for soybean breeders and geneticists. The objectives of this study were to evaluate maturity, plant height, seed weight, and yield in a diverse soybean accession panel, to conduct a genome-wide association study (GWAS) for these traits and identify SNP markers associated with the four traits, and to assess genomic selection (GS) accuracy. Results A total of 250 soybean accessions were evaluated for maturity, plant height, seed weight, and yield over three years. This panel was genotyped with a total of 10,259 high quality SNPs postulated from genotyping by sequencing (GBS). GWAS was performed using a Bayesian Information and Linkage Disequilibrium Iteratively Nested Keyway (BLINK) model, and GS was evaluated using a ridge regression best linear unbiased predictor (rrBLUP) model. The results revealed that a total of 20, 31, 37, 31, and 23 SNPs were significantly associated with the average 3-year data for maturity, plant height, seed weight, and yield, respectively; some significant SNPs were mapped into previously described loci ( E2 , E4 , and Dt1 ) affecting maturity and plant height in soybean and a new locus mapped on chromosome 20 was significantly associated with plant height; Glyma.10g228900 , Glyma.19g200800 , Glyma.09g196700 , and Glyma.09g038300 were candidate genes found in the vicinity of the top or the second best SNP for maturity, plant height, seed weight, and yield, respectively; a 11.5-Mb region of chromosome 10 was associated with both seed weight and yield; and GS accuracy was trait-, year-, and population structure-dependent. Conclusions The SNP markers identified from this study for plant height, maturity, seed weight and yield can be used to improve the four agronomic traits through marker-assisted selection (MAS) and GS in soybean breeding programs. After validation, the candidate genes can be transferred to new cultivars using SNP markers through MAS. The high GS accuracy has confirmed that the four agronomic traits can be selected in molecular breeding through GS.


2021 ◽  
Vol 12 ◽  
Author(s):  
Nagenahalli Dharmegowda Rathan ◽  
Deepmala Sehgal ◽  
Karthikeyan Thiyagarajan ◽  
Ravi Singh ◽  
Anju-Mahendru Singh ◽  
...  

The development of nutritionally enhanced wheat (Triticum aestivum L.) with higher levels of grain iron (Fe) and zinc (Zn) offers a sustainable solution to micronutrient deficiency among resource-poor wheat consumers. One hundred and ninety recombinant inbred lines (RILs) from ‘Kachu’ × ‘Zinc-Shakti’ cross were phenotyped for grain Fe and Zn concentrations and phenological and agronomically important traits at Ciudad Obregon, Mexico in the 2017–2018, 2018–2019, and 2019–2020 growing seasons and Diversity Arrays Technology (DArT) molecular marker data were used to determine genomic regions controlling grain micronutrients and agronomic traits. We identified seven new pleiotropic quantitative trait loci (QTL) for grain Zn and Fe on chromosomes 1B, 1D, 2B, 6A, and 7D. The stable pleiotropic QTL identified have expanded the diversity of QTL that could be used in breeding for wheat biofortification. Nine RILs with the best combination of pleiotropic QTL for Zn and Fe have been identified to be used in future crossing programs and to be screened in elite yield trials before releasing as biofortified varieties. In silico analysis revealed several candidate genes underlying QTL, including those belonging to the families of the transporters and kinases known to transport small peptides and minerals (thus assisting mineral uptake) and catalyzing phosphorylation processes, respectively.


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