GWAS elucidated grain yield genetics in Indian spring wheat under diverse water conditions.

KEY MESSAGE: Underpinned natural variations and key genes associated with yield under different water regimes, and identified genomic signatures of genetic gain in the Indian wheat breeding program. A novel KASP marker for TKW under water stress was developed and validated. A comprehensive genome-wide association study was conducted on 300 spring wheat genotypes to elucidate the natural variations associated with grain yield and its eleven contributing traits under fully irrigated, restricted water, and simulated no water conditions. Utilizing the 35K Wheat Breeders' Array, we identified 1155 quantitative trait nucleotides (QTNs), with 207 QTNs exhibiting stability across diverse conditions. These QTNs were further delimited into 539 genomic regions using a genome-wide LD value of 3.0 Mbp, revealing pleiotropic control across traits and conditions. Sub-genome A was significantly associated with traits under irrigated conditions, while sub-genome B showed more QTNs under water stressed conditions. Favourable alleles with significantly associated QTNs were delineated, with a notable pyramiding effect for enhancing trait performance. Additionally, allele of only 921 QTNs significantly affected the population mean. Allele profiling highlighted C-306 as a most potential source of drought tolerance. Moreover, 762 genes overlapping significant QTNs were identified, narrowing down to 27 putative candidate genes overlapping 29 novel and functional SNPs expressing (≥ 0.5 tpm) relevance across various growth conditions. A new KASP assay was developed, targeting a gene TraesCS2A03G1123700 regulating thousand kernel weight under severe drought condition. Genomic selection models (GBLUP, BayesB, MxE, and R-Norm) demonstrated an average prediction accuracy of 0.06-0.58 across environments, indicating potential for trait selection. Retrospective analysis of the Indian wheat breeding program supported a genetic gain in GY at the rate of ca. 0.56% per breeding cycle, since 1960, supporting the identification of genomic signatures driving trait selection and genetic gain. These findings offer insight into improving the rate of genetic gain in wheat breeding programs globally.

GWAS to Identify Novel QTNs for WSCs Accumulation in Wheat Peduncle Under Different Water Regimes.

Water-soluble carbohydrates (WSCs) play a vital role in water stress avoidance and buffering wheat grain yield. However, the genetic architecture of stem WSCs' accumulation is partially understood, and few candidate genes are known. This study utilizes the compressed mixed linear model-based genome wide association study (GWAS) and heuristic post GWAS analyses to identify causative quantitative trait nucleotides (QTNs) and candidate genes for stem WSCs' content at 15 days after anthesis under different water regimes (irrigated, rainfed, and drought). Glucose, fructose, sucrose, fructans, total non-structural carbohydrates (the sum of individual sugars), total WSCs (anthrone based) quantified in the peduncle of 301 bread wheat genotypes under multiple environments (E01-E08) pertaining different water regimes, and 14,571 SNPs from "35K Axiom Wheat Breeders" Array were used for analysis. As a result, 570 significant nucleotide trait associations were identified on all chromosomes except for 4D, of which 163 were considered stable. A total of 112 quantitative trait nucleotide regions (QNRs) were identified of which 47 were presumable novel. QNRs qWSC-3B.2 and qWSC-7A.2 were identified as the hotspots. Post GWAS integration of multiple data resources prioritized 208 putative candidate genes delimited into 64 QNRs, which can be critical in understanding the genetic architecture of stem WSCs accumulation in wheat under optimum and water-stressed environments. At least 19 stable QTNs were found associated with 24 prioritized candidate genes. Clusters of fructans metabolic genes reported in the QNRs qWSC-4A.2 and qWSC-7A.2. These genes can be utilized to bring an optimum combination of various fructans metabolic genes to improve the accumulation and remobilization of stem WSCs and water stress tolerance. These results will further strengthen wheat breeding programs targeting sustainable wheat production under limited water conditions.

Surgical management of acromegaly: Long term functional outcome analysis and assessment of recurrent/residual disease.

CONTEXT: Functional growth hormone producing adenomas have long-term deleterious effects on the visual apparatus, the cardiovascular and musculoskeletal systems, and often predispose to malignancies. Since persistence of acromegaly affects outcome and quality of life, therapeutic interventions become mandatory. AIM: This study represents an analysis of long-term clinical and endocrinal outcome of 115 patients of acromegaly after surgical management. SETTING AND DESIGN: Tertiary care retrospective study. MATERIALS AND METHODS: One hundred and fifteen patients (male:female ratio: 1:1.09) with acromegalic features were studied. Apart from acromegalic features, their main clinical presentation also included headache, diminution of vision, field defects, ptosis, irregular menstruation, diabetes insipidus, diabetes mellitus and hypertension. Six of them presented with apoplexy. Their preoperative endocrinal evaluation included basal and suppressed growth hormone (GH), prolactin and thyroid levels. On the basis of axial and coronal CT scan or multiplanar MR imaging or both, the tumors were classified according to their suprasellar and parasellar extension (Hardy's grade). Transnasal trans-sphenoidal surgery (TSS) (n = 37) and sublabial, rhinoseptal TSS (n = 72) were the preferred approaches. Six patients with significant parasellar extensions underwent trans-cranial explorations. The patients were followed up at 6 and 12 weeks and then at 6 monthly intervals. Hormonal and CT/MR evaluation were also done. Attainment of random GH value less than 2.5 µg/L, and the nadir GH value after oral glucose tolerance test (OGTT) less than 1 µg/L were used as the criteria of cure. FINDINGS: The patients were preoperatively in Hardy's tumor grade 0 (29), A (21), A+E (3), B (21), B+E (5), C (9), C+E (10), D (1) D+E (11), E (5), respectively. One hundred and one patients were available for follow-up (FU; median FU duration: 84 months; range: 6 to 132 months). Surgical cure was achieved in 73 patients following the first surgery; and, in 10 additional patients following a second intervention. No patient with a preoperative grade 0, A, B, C had a recurrence after attaining the initial remission. Recurrence after an initial cure occurred in 7 patients (overall remission rate following surgery: 75.24%). The preoperative grade of the latter patients was A+E:1, B+E:1, C+E:1, D:1, D+E:2, E:1, respectively. All these patients underwent subsequent radiotherapy (RT). The twelve patients with persistent symptoms and high GH levels following surgery underwent RT; six others with improved symptoms despite high GH levels were kept under strict observation. There was no surgical mortality. CONCLUSIONS: A high remission rate without significant morbidity could be achieved following surgical intervention in acromegalic patients. Following surgery, tumors with greater than or equal to 3 cm suprasellar height and without parasellar extension had no clinical recurrence at FU. A continuous monitoring is mandatory to pick up relapsed cases as well as those who develop delayed signs of hypopituitarism. A subset of patients who show clinical improvement following surgery but still have higher GH levels may be followed up without additional therapy unless clinical signs reappear or the serum GH levels progressively increase.