Abiotic stresses adversely affect rice yield and productivity, especially under the changing climatic scenario. Exposure to multiple abiotic stresses acting together aggravates these effects. The ...projected increase in global temperatures, rainfall variability, and salinity will increase the frequency and intensity of multiple abiotic stresses. These abiotic stresses affect paddy physiology and deteriorate grain quality, especially milling quality and cooking characteristics. Understanding the molecular and physiological mechanisms behind grain quality reduction under multiple abiotic stresses is needed to breed cultivars that can tolerate multiple abiotic stresses. This review summarizes the combined effect of various stresses on rice physiology, focusing on grain quality parameters and yield traits, and discusses strategies for improving grain quality parameters using high-throughput phenotyping with
approaches.
Genetic variability and correlation studies provide basic information concerning the genetic properties of the population based on which, breeding methods could be formulated for further improvement ...of the crop. The estimates of heritability, coefficients of variability, genetic advance and trait association were computed for eleven yield related traits in F2:3 segregating populations of biparental crosses under slightly sodic condition. Analysis of variance revealed significant differences for the traits studied except, effective tillers per plant, panicle length and test weight, indicating the existence of high genetic variability among the lines. Estimates of phenotypic coefficients of variation (PCV) were higher than genotypic coefficient of variation (GCV) for all the characters studied, indicating considerable effect of environment. Moderate heritability accompanied with high genetic advance was recorded for filled grains and unfilled grains per panicle which, indicates heritability is most likely due to additive gene effect and selection for the traits will be effective. Traits like: effective tillers per plant, panicle length, filled grains per panicle and total grains per panicle that showed, positive and significant association with grain yield per plant, could be useful for breeders in any breeding program for further improvement of the traits under sodic condition.
Introduction/Aims
Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene resulting in the absence of dystrophin. Casimersen is a phosphorodiamidate morpholino oligomer designed to ...bypass frameshift DMD mutations and produce internally truncated, yet functional, dystrophin protein in patients amenable to exon 45 skipping. Our primary study objective was to evaluate safety and tolerability of casimersen; the secondary objective was to characterize the plasma pharmacokinetics.
Methods
This multicenter, phase 1/2 trial enrolled 12 participants (aged 7‐21 years, who had limited ambulation or were nonambulatory) and comprised a 12‐week, double‐blind dose titration, then an open‐label extension for up to 132 weeks. During dose titration, participants were randomized 2:1 to weekly casimersen infusions at escalating doses of 4, 10, 20, and 30 mg/kg (≥2 weeks per dose), or placebo.
Results
Participants received casimersen for a mean 139.6 weeks. Treatment‐emergent adverse events (TEAEs) occurred in all casimersen‐ and placebo‐treated participants and were mostly mild (over 91.4%) and unrelated to casimersen or its dose. There were no deaths, dose reductions, abnormalities in laboratory parameters or vital signs, or casimersen‐related serious AEs. Casimersen plasma concentration increased with dose and declined similarly for all dose levels over 24 hours postinfusion. All pharmacokinetic parameters were similar at weeks 7 and 60.
Discussion
Casimersen was well tolerated in participants with DMD amenable to exon 45 skipping. Most TEAEs were mild, nonserious, and unrelated to casimersen. Plasma exposure was dose proportional with no suggestion of plasma accumulation. These results support further studies of casimersen in this population.
Abstract
Introduction/Aims
Duchenne muscular dystrophy (DMD) is caused by mutations in the
DMD
gene resulting in the absence of dystrophin. Casimersen is a phosphorodiamidate morpholino oligomer ...designed to bypass frameshift
DMD
mutations and produce internally truncated, yet functional, dystrophin protein in patients amenable to exon 45 skipping. Our primary study objective was to evaluate safety and tolerability of casimersen; the secondary objective was to characterize the plasma pharmacokinetics.
Methods
This multicenter, phase 1/2 trial enrolled 12 participants (aged 7‐21 years, who had limited ambulation or were nonambulatory) and comprised a 12‐week, double‐blind dose titration, then an open‐label extension for up to 132 weeks. During dose titration, participants were randomized 2:1 to weekly casimersen infusions at escalating doses of 4, 10, 20, and 30 mg/kg (≥2 weeks per dose), or placebo.
Results
Participants received casimersen for a mean 139.6 weeks. Treatment‐emergent adverse events (TEAEs) occurred in all casimersen‐ and placebo‐treated participants and were mostly mild (over 91.4%) and unrelated to casimersen or its dose. There were no deaths, dose reductions, abnormalities in laboratory parameters or vital signs, or casimersen‐related serious AEs. Casimersen plasma concentration increased with dose and declined similarly for all dose levels over 24 hours postinfusion. All pharmacokinetic parameters were similar at weeks 7 and 60.
Discussion
Casimersen was well tolerated in participants with DMD amenable to exon 45 skipping. Most TEAEs were mild, nonserious, and unrelated to casimersen. Plasma exposure was dose proportional with no suggestion of plasma accumulation. These results support further studies of casimersen in this population.
The study aimed to estimate the phenotypic variability for LTN as well as yield traits, genotypic variability for Lr34, Lr46 and Lr67 and to investigate the association between genotypic and ...phenotypic variability for LTN and yield traits. Two hundred fifty wheat genotypes were screened for the presence of Leaf Tip Necrosis (LTN), a phenotypic marker of wheat resistance to leaf rust infection following Randomized Block Design. Of which 77 genotypes showed variable expression of LTN. Twelve yield traits were analyzed that showed highly significant differences. All these 77 genotypes were validated for the presence of three genes using respective markers viz., csLV34 for Lr34; Xwmc44 for Lr46, and Xcfd71 for Lr67. Out of 77 genotypes, 19 genotypes showed the presence of a single gene (7 with Lr34, 5 with Lr46, and 7 with Lr67), 13 genotypes had all the 3 genes, 14 with a combination of 2 genes and 31 had not shown the presence of any gene. Wheat genotypes within the individual presence of three genes increased the LTN area but their combination, reduced the thousand grain weight, LTNA, and the plot yield. All three genes individually or in combination increased the leaf area. Lr67 alone and in combination with Lr46 reduced the plot yield of wheat genotypes. Interestingly, LTNA had no significant correlation with any of the traits analyzed in this study. Leaf area showed a negative correlation with days to heading, glaucousness index, and thousand grain weight (TGW). NDVI-3 (at dough stage) showed a positive correlation with plot yield and TGW but had a negative association with the leaf area. High heritability coupled with high genetic advance was observed for leaf area (99.70%, 29.52%), LTNA (99.35%), 1000- grain weight (95.37%), grains per spike (93.65%, 17%), and days to headings (88.04%).
Plant architecture has a substantial impact on photosynthesis, which leads to increased yield production. Many plant architecture characters are quantitative in inheritance, making bi-parental QTL ...mapping difficult to discover all the genomic regions underpinning these traits. GWAS approach is the most promising approach to dissect these traits. We developed candidate gene-based SSR (cgSSR) markers and used them in a GWAS study on a panel of diverse rice genotypes evaluated over three seasons for three plant type characters and grain yield. A total of 17 marker-trait associations were detected for four observed traits. Three markers derived from genes
OsGID1
,
OsFBK12
and
OsMADS18
showed association with traits that were previously reported to be influenced by these genes. Many novel associations of genes with the traits were detected that had never been reported before. Three markers showed association with two traits each; these markers can be utilized in the simultaneous improvement of both traits. Trait-associated cgSSR markers derived from corresponding or related genes ensure their utility in direct allele selection, while other linked markers aid in allele selection indirectly altering the phenotype of interest. These significantly associated cgSSR markers with plant-type traits can be used in actual plant breeding to accumulate favourable alleles for these traits via marker assisted breeding.
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