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A total of 263 accessions representing a cross section of the recently developed common wheat genotypes in India showing flag leaf tip necrosis (LTN) were characterized for the LTN-associated pleiotropic adult plant resistance (PAPR) genes, Lr34/Yr18/Sr57 (Lr34 +), Lr46/Yr29/Sr58 (Lr46 +), and Lr67/Yr46/Sr55 (Lr67 +) using closely linked molecular markers. They were evaluated for seedling resistance to important rust pathotypes, and for multi-environmental field resistance to the three rusts. About 79% of the genotypes carried the PAPR genes singly or in different two genes’ combinations. The genes Lr67 + and Lr34 + occurred much more frequently than Lr46 + . While field resistance to leaf and stem rusts was usually associated with seedling resistance, that to stripe rust was based largely on the adult-plant resistance. Intermediate to low levels of resistance were provided by the three PAPR genes individually, and no clear-cut additive effects on rust resistance were apparent among the various gene combinations. Considerable diversity was observed for resistance to all the three wheat rusts. Additional genes for resistance were indicated in many genotypes which need to be characterized. The identified diverse sources of multiple rust resistance can be utilized in breeding for rust resistance along with desired agronomic traits.

Genetic resources are the fundamental source of diversity to plant breeders for improvement of desired traits. However, large germplasm set is difficult to preserve and use as working collection in genetic studies, hence in the present study evaluation of genetic diversity of 604 durum germplasm originated from different geographical areas and development of core collection for representation of diverse germplasm for working collection was done. Six hundred and four durum germplasm were sown in augmented design and data were recorded for eight quantitative characters including agronomic and grain quality traits. Descriptive statistics showed large variation for all studied traits. Box plot analysis for nine different sets of germplasm showed a large variation for agronomic traits and quality traits. Principal component analysis for the first four principal components explained 71% of the cumulative variation and grouped germplasm in the main two groups. The core germplasm set was developed using corehunter package with 10% cutoff and hence 60 germplasm entries make representation in core subset based on maximum diversity and minimum redundancy. The maximum contribution to core germplasm was by each CZ (Central Zone) breeding lines and D numbers (23%) followed by exotic other lines (20%). The developed core subset was validated using multivariate analysis such as Shannon diversity index, comparison of means and homogeneity of error variances using the Levene’s test. The results described in this study will be useful for durum wheat breeders for the development of varieties with high end-use quality.

Spot blotch (SB), caused by Bipolaris sorokiniana, is a devastating disease of wheat globally, especially in South Asia and South America. Understanding the genetics of resistance to SB is important for developing breeding strategies to improve resistance. A panel of 301 genotypes from Afghanistan was phenotyped over two crop seasons using a mixture of virulent B. sorokiniana isolates and genotyped using DArTSeq to obtain genome‐wide markers. Fifty genotypes (16.6%) showed disease scores less than the resistant control. Principal component analysis using the genotypic data clustered the genotypes into five different groups. Among models used for genome‐wide association mapping, the multilocus mixed model, and fixed and random model circulating probability unification algorithms were most effective in identifying significant marker‐trait associations (MTA). Twenty‐five MTAs at p ≤ .001 were identified on chromosomes 1A, 1B, 1D, 2B, 2D, 3A, 3B, 4A, 5A, 5B, 6A, 7A, and 7D, indicating the quantitative nature of resistance to SB. Phenotypic variation explained by these markers ranged from 2.0% to 17.7%, and genomic regions on the chromosomes 1D, 2D, 3A, 3B, 4A, 5A, and 5B coincided with loci identified in previous studies. Three single nucleotide polymorphism (SNP) markers on chromosomes 1B (SNP 1113207) and 5A (SNPs 5411867 and 998276) were significant in both crop seasons as well as in the combined analysis across seasons. Marker 5411867 is close to Vrn‐A1, shown to be associated with SB in previous studies. Furthermore, among known SB resistance genes, Sb2 on chromosome 5B was predicted to be significant in this panel.

Wheat (Triticum aestivum L.) crop health assumes unprecedented significance in being the second most important staple crop of the world. It is host to an array of fungal pathogens attacking the plant at different developmental stages and accrues various degrees of yield losses owing to these. Tilletia indica that causes Karnal bunt (KB) disease in wheat is one such fungal pathogen of high quarantine importance restricting the free global trade of wheat besides the loss of grain yield as well as quality. With global climate change, the disease appears to be shifting from its traditional areas of occurrence with reports of increased vulnerabilities of new areas across the continents. This KB vulnerability of new geographies is of serious concern because once established, the disease is extremely difficult to eradicate and no known instance of its complete eradication using any management strategy has been reported yet. The host resistance to KB is the most successful as well as preferred strategy for its mitigation and control. However, breeding of KB resistant wheat cultivars has proven to be not so easy, and the low success rate owes to the scarcity of resistance sources, extremely laborious and regulated field screening protocols delaying identification/validation of putative resistance sources, and complex quantitative nature of resistance with multiple genes conferring only partial resistance. Moreover, given a lack of comprehensive understanding of the KB disease epidemiology, host-pathogen interaction, and pathogen evolution. Here, in this review, we attempt to summarize the progress made and efforts underway toward a holistic understanding of the disease itself with a specific focus on the host-pathogen interaction between T. indica and wheat as key elements in the development of resistant germplasm. In this context, we emphasize the tools and techniques being utilized in development of KB resistant germplasm by illuminating upon the genetics concerning the host responses to the KB pathogen including a future course. As such, this article could act as a one stop information primer on this economically important and re-emerging old foe threatening to cause devastating impacts on food security and well-being of communities that rely on wheat.

Sorghum is a major staple globally and biofortifying sorghum with increased grain iron and zinc complements ongoing efforts to combat micronutrient malnutrition. Limited information available on the nature and magnitude of gene effects for grain iron and zinc. So generation mean analysis was done using four crosses, ICSB 52 × IS 13211, ICSB 52 × SPV 1359, IS 20843 × IS 2248 and IS 2248 × IS 20843. Six generations, P1, P2, F1, F2, B1 and B2, were generated for each of these crosses which were evaluated during the postrainy season 2012–13. The mean sum of squares due to generations were significant for days to flowering, plant height, grain yield/plant, 100-grain weight, and grain Fe and Zn. Generation mean studies revealed the presence of both additive and dominant gene interactions in inheritance of agronomic traits. Duplicative epistasis was observed for days to flowering, plant height, grain yield/plant, 100-grain weight, and grain Zn with a predominance of dominant gene action in inheritance of these traits. Panicle length, panicle width, and grain Fe showed both additive and dominance gene effects, with higher magnitude of dominance. This information can be utilized in developing sorghum lines with high grain Fe and Zn.

The low grain iron and zinc densities are well documented problems in food crops, affecting crop nutritional quality especially in cereals. Sorghum is a major source of energy and micronutrients for majority of population in Africa and central India. Understanding genetic variation, genotype × environment interaction and association between these traits is critical for development of improved cultivars with high iron and zinc. A total of 336 sorghum RILs (Recombinant Inbred Lines) were evaluated for grain iron and zinc concentration along with other agronomic traits for 2 years at three locations. The results showed that large variability exists in RIL population for both micronutrients (Iron = 10.8 to 76.4 mg kg−1 and Zinc = 10.2 to 58.7 mg kg−1, across environments) and agronomic traits. Genotype × environment interaction for both micronutrients (iron and zinc) was highly significant. GGE biplots comparison for grain iron and zinc showed greater variation across environments. The results also showed that G × E was substantial for grain iron and zinc, hence wider testing needed for taking care of G × E interaction to breed micronutrient rich sorghum lines. Iron and zinc concentration showed high significant positive correlation (across environment = 0.79; p < 0.01) indicating possibility of simultaneous effective selection for both the traits. The RIL population showed good variability and high heritabilities (>0.60, in individual environments) for Fe and Zn and other traits studied indicating its suitability to map QTL for iron and zinc.