The use of untapped plant genetic resources of wheat (Triticum spp.) can enhance its productivity. In the present study, we characterized 22,416 accessions of three different species of wheat conserved in the Indian National Genebank using 23 qualitative and 12 quantitative traits to develop a core set. These accessions were highly diverse on the basis of range, coefficient of variation, and Shannon–Weaver diversity index. Initial grouping was done on the bases of species and origin, and thereafter, agromorphological data were used to develop core sets for each species group using the heuristic approach with PowerCore. Finally, a composite core set was constituted comprising 2,226 accessions, which included 1,779 accessions of bread wheat (T. aestivum L.), 394 of durum wheat [T. turgidum L. subsp. durum (Desf.) van Slageren], and 53 of emmer wheat [T. dicoccon Schrank; syn. T. turgidum L. subsp. dicoccon (Schrank) Thell]. The core set was validated under field conditions. Also, the coincidence rate of range (CR) (bread wheat, 85.78%; durum wheat, 87.52%; and emmer wheat, 95.34%) and variable rate of the coefficient of variation (VR) (bread wheat, 174.9%; durum wheat, 136.5%; and emmer wheat, 105.81%) were more than the threshold values of 80 and 100%, respectively. The phenotypic correlations among different traits attributable to coadapted gene complexes and total variation shown by principal components in the entire set were also mostly preserved in the core set. The composite wheat core and the trait‐specific germplasm sets identified would serve as valuable resources for global wheat improvement programs.

Plant genetic resources, the source of genetic diversity provides a broad genetic foundation for plant breeding and genetic research, however, large germplasm resources are difficult to preserve, evaluate and use. Construction of core and mini core collections is an efficient method for managing genetic resources and undertaking intensive surveys of natural variation, including the phenotyping of complex traits and genotyping of DNA polymorphisms allowing more efficient utilization of genetic resources. A mega characterization and evaluation programme of the entire cultivated gene pool of wheat conserved in the National Genebank, India was undertaken. Wheat accessions with limited seed quantity, were multiplied in the off-season nursery at IARI Regional Station, Wellington during rainy season 2011 and the entire set of 22,469 wheat accessions were characterized and evaluated at CCS HAU, Hisar, Haryana during winter season 2011-12 for 34 characters including 22 highly heritable qualitative, and 12 quantitative parameters. The core sets were developed using PowerCore Software with stepwise approach and grouping method and validated using Shannon-Diversity Index and summary statistics. Based on Shannon-Diversity index, PowerCore with stepwise approach was found better than PowerCore with grouping. The core set included 2,208 accessions comprising 1,770 T. aestivum, 386 T. durum, and 52 T. dicoccum accessions as a representative of the total diversity recorded in the wheat germplasm. The core set developed will be further validated at different agro-climatic conditions and will be utilized for development of mini core set to enhance the utilization by wheat researchers and development of climate resilient improved varieties.

Leaf rust ( Puccinia triticina Eriks.) is a fungal disease of wheat ( Triticum spp.), which causes considerable yield loss. Adult plant resistance (APR) is one of the most sustainable approaches to control leaf rust. In this study, field-testing was carried out across ten different locations, followed by molecular screening, to detect the presence of APR genes, Lr34 +, Lr46 +, Lr67 + and Lr68 in Indian wheat germplasm. In field screening, 190 wheat accessions were selected from 6,319 accessions based on leaf tip necrosis (LTN), disease severity and the average coefficient of infection. Molecular screening revealed that 73% of the accessions possessed known APR genes either as single or as a combination of two or three genes. The occurrence of increased LTN intensity, decreased leaf rust severity and greater expression of APR genes were more in relatively cooler locations. In 52 lines, although the presence of the APR genes was not detected, it still displayed high levels of resistance. Furthermore, 49 accessions possessing either two or three APR genes were evaluated for stability across locations for grain yield. It emerged that eight accessions had wider adaptability. Resistance based on APR genes, in the background of high yielding cultivars, is expected to provide a high level of race non-specific resistance, which is durable.

A field experiment was conducted to developed improved wheat and soil production system through integrated nutrient management (INM) and efficient planting system (EPS) in split plot design (SPD) with 20 treatment combinations. Treatments were consist of two planting systems (conventional and FIRB) and 10 fertility treatments viz., control, RDF, 75% RDF + FYM, 75% RDF + FYM + Zn, 75% RDF + FYM + Biofertilizer (BF) , 75% RDF + FYM + BF + Zn, RDF + FYM, RDF + FYM + Zn, RDF + FYM + BF and RDF + FYM + BF + Zn. The yield contributing characters of wheat viz., number of spikes / plant and number of grains/ spike were recorded significantly higher when the crop was supplied with combined application of RDF or 75% RDF along with FYM, biofertilizer and zinc over control and treatment receiving RDF only. In case of wheat yield, 10.8 and 11.3 per cent higher yield were registered with FIRB planting system over conventional system during 2007-08 and 2008-09. However in case of integrated nutrient management, RDF + FYM + BF + Zn treatment produced 50.39 and 52.73 q/ha wheat yield respectively. The grain and straw yields increased significantly with treatment RDF + FYM + Zn over control and RDF alone. The increase in grain yield with application of RDF + FYM + BF + Zn over RDF alone was 16.8 and 14.1 per cent during 2007-08 and 2008-09, respectively. The treatment receiving fertilizer showed a higher harvest index over unfertilized control. No significant difference between planting systems was recorded in respect of available nitrogen, phosphorus, potassium and organic carbon status of soil after harvest of crop during both the years of investigation. However, a higher net positive NPK balance under FIRB planting was observed over conventional planting system. A lower bulk density in the surface soil was observed under FIRB planting system as compared to conventional planting system during both years of field study. The FIRB system of planting and combined application of RDF or 75% RDF along with FYM, biofertilizers and zinc not only gave higher productivity and profitability of wheat but also have positive effect on soil physico-chemical properties which resulted into better rhizospheroc environment.