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Exposing genetic material with physical mutagens can create novel genetic resources capable of combating different stresses. High throughput GBS-DArTseq™ assay was deployed to estimate genetic diversity of 33 newly developed stable wheat mutants as compared to the wild type. The identified 1,57,608 PAVs markers were randomly distributed across wheat chromosomes and sub-genomes with the highest number detected on Chr-7D (2877) and Chr-7B (2711). The B sub-genome contained the most PAVs followed by D and A-sub genome. Among mutant lines, Pb-M-2061 and Pb-M-59 had the highest PAV count, while Pb-M-605 and Pb-M-196 had the lowest. A total of 7,910 PAVs were consistently present over all replicates, with 3,252 specifically present in mutants and absent in wild type. The maximum PAVs (1480) were found in Pb-M-1027 and Pb-M-1323 (656). Functional characterization revealed that out of 3,252, 1,238 were found in wheat transcriptome database that contained 152 characterized and 1,196 uncharacterized genes. COGs and GO-terms analysis linked many PAVs with pathways involving signaling, metabolism and defense. Maximum number of gene-containing PAVs were identified in Pb-M-1027, Pb-M-2302 and Pb-M-1323 which were involved in tolerance to diseases and abiotic stresses, improved photosynthetic efficiency, larger grain size, increased grain yield and harvest index pathways. This study provides valuable insights into the genetic diversity and potential agronomic benefits of PAVs in wheat mutant lines. These findings can help molecular geneticist and breeders for exploiting the induced genetic diversity for unravelling the genetic circuits as well as exploiting in wheat breeding for developing resilient cultivars. [ABSTRACT FROM AUTHOR]

To the extent of our knowledge, applications of DNA markers in marker-assisted breeding of cotton are handicapped due to low genetic diversity in cotton germplasm. Cotton leaf curl disease, a disease of viral origin, has substantially depressed cotton production in Pakistan, and this disease is also an emerging threat to the neighboring cotton-growing countries like China and India. The present study was designed to identify DNA markers, predominately simple sequence repeats (SSRs), associated with tolerance and/or resistance to the disease. Based upon 2 years of disease-screening field experiments, a total of 10 cotton genotypes (five highly tolerant, four highly susceptible, and one immune) of diverse origin were selected from the available cotton germplasm (~1200 accessions) of the National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan. In total, 322 SSRs derived from bacterial artificial chromosome end sequences of Gossypium raimondii (one of the progenitor species of cultivated tetraploid cotton) were screened. Out of these, 65 primer pairs were found polymorphic, and the extent of genetic similarity was in the range of 81.7% to 98.7%. A similarity matrix was used for studying their phylogenetic relationship using unweighted pair-group method with arithmetic means (UPGMA) analysis. The dendrogram showed the grouping of the genotypes into two distinct clusters comprising tolerant and susceptible genotypes, respectively. Out of the polymorphic markers, two SSR markers, PR-91 and CM-43, that were amplified only in tolerant genotypes showed significant association with resistance to the disease. These preliminary results set the stage for initiating in-depth marker-trait association studies, which will be instrumental for initiating marker-assisted breeding in cotton. [ABSTRACT FROM AUTHOR]

Exploiting new genetic resources is an effective way to achieve sustainable wheat production. To this end, we exposed wheat seeds of the "Punjab-11" cultivar to gamma rays. A total of 32 stable mutants (M7) were developed, followed by characterization by conducting multilocation trials over two seasons. Principal component analysis (PCA) showed that the first six components accounted for 90.28% of the total variation among the plant height, tillers per plant, 1000-kernel weight, grain yield, and quality traits. All mutants were grouped into three clusters based on high yield index values. The genotype by trait (GT) bi-plot revealed significant associations between yield and its components among the mutants. Positive correlations were estimated for tillers per plant, plant height, 1000-kernel weight, and grain yield; however, yield components showed negative associations with protein, moisture, and gluten contents. The mutant lines Pb-M-59 waxy, Pb-M-1272 waxy, Pb-M-2260, Pb-M-1027 waxy, Pb-M-1323 waxy, and Pb-M-1854 exhibited maximum grain yield, 1000-grain weight, and tillers per plant values. Likewise, Pb-M-2725, Pb-M-2550, and Pb-M-2728 were found to be the best mutant lines in terms of grain quality; thus, the use of gamma radiation is effective in improving the desirable traits, including yield and grain quality. It is suggested that these traits can be improved beyond the performance of corresponding traits in their parent genotypes. The newly produced mutants can also be used to explore the genetic mechanisms of complex traits in the future. [ABSTRACT FROM AUTHOR]