Explore the vast range of titles available.

Climate change augments the risk to food security by inducing drought stress and a drastic decline in global rice production. Plant growth-promoting bacteria (PGPB) have been known to improve plant growth under drought stress. Here in the present study, we isolated, identified, and well-characterized eight drought-tolerant bacteria from the rice rhizosphere that are tolerant to 20% PEG-8000. These strains exhibited multiple plant growth-promoting traits, i.e., 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, exopolysaccharide production, phosphate (P)-solubilizing activity (51–356 µg ml -1 ), indole-3 acetic acid (IAA) production (14.3–46.2 µg ml -1 ), and production of organic acids (72–178 µg ml -1 ). Inoculation of bacterial consortium ( Bacillus subtilis NM-2, Brucella haematophilum NM-4, and Bacillus cereus NM-6) significantly improved seedling growth and vigor index (1009.2-1100) as compared to non-inoculated stressed plants (630-957). Through rhizoscanning, efficiency of the consortium was validated by improved root parameters such as root length (17%), diameter, and surface area (18%) of all tested genotypes as compared with respective non-inoculated stressed treatments. Furthermore, the response of consortium inoculation on three rice genotypes was positively correlated with improved plant growth and drought stress ameliorating traits by the accumulation of osmoprotectant, i.e., proline (85.8%–122%), relative water content (51%), membrane stability index (64%), and production of antioxidant enzymes to reduce oxidative damage by reactive oxygen species. A decrease in temperature and improved chlorophyll content of inoculated plants were found using infrared thermal imaging and soil plant analyzer development (SPAD), respectively. The key supporting role of inoculation toward stress responses was validated using robust techniques like infrared thermal imaging and an infrared gas analyzer. Furthermore, principal component analysis depicts the contribution of inoculation on stress responses and yield of tested rice genotypes under water stress. The integration of drought-tolerant rice genotype (NIBGE-DT02) and potential bacterial strains, i.e., NM-2, NM-4, and NM-6, can serve as an effective bioinoculant to cope with water scarcity under current alarming issues related to food security in fluctuating climate.

Basmati is a premium quality rice, famous for its aroma, fine grain, and excellent cooking qualities. However, it is highly susceptible to bacterial leaf blight (BLB). To develop BLB resistant Basmati rice varieties, we transferred three (03) BLB resistance genes namely Xa4, xa5, Xa21 from a coarse yet BLB-resistant variety, IRBB57, developed by International Rice Research Institute into fine-quality rice variety, Super Basmati, through marker-assisted breeding. The background parent genome was recovered performing several backcrosses using Super Basmati as a recurrent parent to restore the bona fide Basmati character. The introgression of BLB resistance genes was followed by foreground selection using DNA-markers tightly linked with BLB resistance genes. The recovery of the Basmati parent genome (Background Selection) was determined using two different marker systems. Simple Sequence Repeats and Single Nucleotide Polymorphism. Several Super Basmati Introgressed (SBIL) lines with the individual as well as different BLB resistance gene combinations were developed. The stable representative SBILs from single, double, and triple gene combinations showing > 90% parent genome recovery were further studied for different attributes particularly to determine their degree of tolerance to the bacterial blight that was studied at two different locations—Philippines and Pakistan. We observed that SBILs carrying a combination of xa5 + Xa21 and Xa4 + xa5 + Xa21 conferred broad-scale resistance against both the highly virulent Pakistani and Philippines Xanthomonas oryzae pv. oryzae strains. The marker-aided background selection coupled with stringent phenotypic selection as well as foreground selection using DNA markers tightly linked with grain quality ensured that SBILs possess the bona fide Basmati character. The performance of key agronomic traits in selected SBILs was comparable with the recurrent parent with no significant agronomic or yield penalty associated with incorporation of the resistance genes, confirming the linkage drag has been minimized. Therefore, in addition to sustaining Basmati rice yield against BLB, the SBILs developed in this study may represent a useful resource for transferring resistance to BLB-susceptible rice varieties.

Super Basmati is an elite variety with extra-long grains and superior quality but its yield is severely affected by water stress. Recombinant inbred lines (RILs) developed from the cross of Super Basmati and IR55419-04 (a coarse grained variety with high yield potential) were used to identify and map yield-related quantitative trait loci (QTLs) under normal field conditions. Genotypes for 244 KASP markers were obtained from 188 F9 RILs and a linkage map constructed of 1369.4 cM, with average marker interval of 10.5 cM. Eleven agronomic traits were phenotyped in RILs and parents. Composite interval mapping and inclusive composite interval mapping model identified 21 common QTLs related to nine agronomic traits; of the QTLs identified, twelve mapped at novel positions. LOD scores ranged from 2.51 for number of filled grains (qFG1.1) to 16.8 for plant height (qPH1.1). Four major effect QTLs could explain 20% of variation related for plant height, hundred-grain weight and grain width. Alleles from IR55419-04 improved grain filling, grain weight and grain width, while alleles from Super Basmati contributed to longer grains, panicles and flag leaves. Putative candidate genes were identified for 18 yield-related QTLs. These results validate the use of KASP genotyping for QTL mapping of yield-related traits in a bi-parental segregating population. SNPs in the QTLs identified in this study can be used in marker assisted selection for yield components to improve Basmati rice.

Background Seeds of super basmati were mutagenized with different ethyl methane sulphonate (EMS) doses for creating genetic variability. Methods and results A total of 48 randomly selected putative EMS mutants of super basmati were analyzed to dissect the genetic diversity by using 25 SSR primers located on twelve chromosomes of rice. SSRs analysis revealed that wide-range of genetic diversity is present among mutants of super basmati. A sum of 91 alleles were identified, out of these, 82 alleles were polymorphic and the rest of nine alleles were monomorphic in nature. The range of allele number was 2–10 with mean of 3.64 alleles/locus. The value of polymorphic information content was range between 0.039 (RM5) and 0.878 (RM44) with mean of 0.439 for each locus. A number of polymorphic markers showed unique bands of various sizes ranges from 75 to 1000 bp, during genetic dissection of mutant population. Dendrogram divided whole mutant population into four major groups. Phylogenic analyses revealed that 40–96%genetic similarity is present among individuals of mutant population. Conclusion It is concluded that EMS induced genetic variability and SSRs markers (RM44, RM154, RM1, RM252, RM334, RM487, RM110 and RM257) could be handy for the selection of rice mutants as parents for functional genomic and molecular breeding program.