Water shortage at precarious growth stages diminishes the wheat production, however regulated deficit irrigation and potassium fertilization ameliorate its adversities to a certain extent. A pot experiment was conducted in 2010-11 and 2011-12 growing seasons to assess the effect of regulated deficit irrigation on yield and water use efficiency of wheat under semiarid region of Pakistan. The growing season was divided into six periods viz: germination, jointing, booting, heading, grain filling and maturity stage. Three regulated deficit irrigation levels (no- soil- water- deficit (H: 80-100% of available water content (AWC)), medium (M) soil water deficit (70 to 80% AWC and severe (L) water deficit (60-70% AWC) were maintained at above mentioned stages in combination with three levels of potassium (0, 200 and 300 kg ha-1 K2O). Soil water contents were measured gravimetrically by weighing pots after 1 to 2 day’s interval throughout the growing season. Potential evapotranspiration (ETp) was calculated using Penman-Montieth model. The actual evapotranspiration (ETa) was calculated using water balance equation and crop coefficient was calculated by dividing the ETa with ETp. The data obtained was analyzed statistically. The results of this study showed that grain yield and water use efficiency in wheat (Sahar-2006) was greatly improved by 23.4 and 15.0% (average of two years) under soil water deficit treatment I3 (MMHMH) with potassium (K2O applied at 300 kg ha-1) as compared to regulated deficit treatment I1 (HMLML) in combination without potassium (K2O applied at 0 kg ha-1). The optimum total irrigation water of 242.9 mm was distributed as 13.7 mm during germination stage, 22.15 mm during jointing, 21.10 mm during booting, 69.95 mm during heading, 58.9 mm during grain filling and 57.05 mm during maturity to fulfill the need of actual evapotranspiration which was required to produce the above mentioned increase in grain yield and other parameters. Root length and mass density were also increased by 35.9 and 35.6% in pot receiving I3 (MMHMH) in combination with K2 over I1 (HMLML) in combination with K0. K nutrition helped in mitigating the negative effects of water stress due to well- developed root system and accelerated the maximum water uptake and improved water use efficiency.

For disorders with X-linked inheritance, variants may be transmitted through multiple generations of carrier females before an affected male is ascertained. Pathogenic RS1 variants exclusively cause X-linked retinoschisis (XLRS). While RS1 is constrained to variation, recurrent variants are frequently observed in unrelated probands. Here, we investigate recurrent pathogenic variants to determine the relative burden of mutational hotspot and founder allele events to this phenomenon. A cohort RS1 variant analysis and standardized classification, including variant enrichment in the XLRS cohort and in RS1 functional domains, were performed on 332 unrelated XLRS probands. A total of 108 unique RS1 variants were identified. A subset of 19 recurrently observed RS1 variants were evaluated in 190 probands by a haplotype analysis, using microsatellite and single nucleotide polymorphisms. Fourteen variants had at least two probands with common variant-specific haplotypes over ~1.95 centimorgans (cM) flanking RS1. Overall, 99/190 of reportedly unrelated probands had 25 distinct shared haplotypes. Examination of this XLRS cohort for common RS1 haplotypes indicates that the founder effect plays a significant role in this disorder, including variants in mutational hotspots. This improves the accuracy of clinical variant classification and may be generalizable to other X-linked disorders.

We assessed genotype-phenotype correlations among the visual, auditory, and olfactory phenotypes of 127 participants with Usher syndrome (USH2) (n =80) or nonsyndromic autosomal recessive retinitis pigmentosa (ARRP) (n = 47) due to USH2A variants, using clinical data and molecular diagnostics from the Rate of Progression in USH2A Related Retinal Degeneration (RUSH2A) study. USH2A truncating alleles were associated with USH2 and had a dose-dependent effect on hearing loss severity with no effect on visual loss severity within the USH2 subgroup. A group of missense alleles in an interfibronectin domain appeared to be hypomorphic in ARRP. These alleles were associated with later age of onset, larger visual field area, better sensitivity thresholds, and better electroretinographic responses. No effect of genotype on the severity of olfactory deficits was observed. This study unveils a unique, tissue-specific USH2A allelic hierarchy with important prognostic implications for patient counseling and treatment trial endpoints. These findings may inform clinical care or research approaches in others with allelic disorders or pleiotropic phenotypes.