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Abstract: Simple sequence repeats (SSRs) are preferred molecular markers because of their abundance, robustness, high reproducibility, high efficiency in detecting variation and suitability for high‐throughput analysis. In this study, an attempt was made to mine and analyse the SSRs from the genomes of two seed‐borne fungal pathogens, viz Ustilago maydis, which causes common smut of maize, and Tilletia horrida, the cause of rice kernel smut. After elimination of redundant sequences, 2,703 SSR loci of U. maydis were identified. Of the remaining SSRS, 44.5% accounted for di‐nucleotide repeats followed by 29.8% and 2.7% tri‐ and tetranucleotide repeats, respectively. Similarly, 2,638 SSR loci were identified in T. horrida, of which 20.2% were di‐nucleotide, 50.4% tri‐ and 20.5% tetra‐nucleotide repeats. A set of 65 SSRs designed from each fungus were validated, which yielded 23 polymorphic SSRs from Ustilago and 21 from Tilletia. These polymorphic SSR loci were also successfully cross‐amplified with the Ustilago segetum tritici and Tilletia indica. Principal coordinate analysis of SSR data clustered isolates according to their respective species. These newly developed and validated microsatellite markers may have immediate applications for detection of genetic variability and in population studies of bunt and smut of wheat and other related host plants. Moreover, this is first comprehensive report on molecular markers suitable for variability studies in wheat seed‐borne pathogens. [ABSTRACT FROM AUTHOR]

Tilletia indica causes the disease Karnal bunt in wheat. The disease is under international quarantine regulations. Comparative mitochondrial (mt) genome analysis of T. indica (KX394364 and DQ993184) and T. walkeri (EF536375) has found 325 to 328 SNPs, 57 to 60 short InDels (from 1 to 13 nt), two InDels (30 and 61 nt) and five (>200 nt) presence/absence variations (PAVs) between the two species. The mt genomes of both species have identical gene order. The numbers of SNPs and InDels between the mt genomes of the two species are approximately nine times of the corresponding numbers between the two T. indica isolates. There are eight SNPs between T. indica and T. walkeri that resulted in amino acid substitutions in the mt genes of cob, nad2 and nad5. In contrast, there is no amino acid substitution in the mt genes of the T. indica isolates from the SNPs found. The five PAVs present in T. indica (DQ993184) are absent in T. walkeri. Four PAVs are more than 1 kb and are not present in every T. indica isolate. Analysis of their presence and absence separates a collection of T. indica isolates into 11 subgroups. Two PAVs have ORFs for the LAGLIDAG endonuclease and two have ORFs for the GIY-YIG endonuclease family, which are representatives of homing endonuclease genes (HEGs). These intron- encoded HEGs confer intron mobility and account for their fluid distribution in T. indica isolates. The small PAV of 221 bp, present in every T. indica isolate and unique to the species, was used as the genetic fingerprint for the successful development of a rapid, highly sensitive and specific loop mediated isothermal amplification (LAMP) assay. The simple procedure of the LAMP assay and the easy detection formats will enable the assay to be automated for high throughput diagnosis. [ABSTRACT FROM AUTHOR]

Rice-wheat is the predominant cropping system and contributes more than 70% of food grain production in India. However, major problem in this system is depletion and deterioration of water resources. Therefore, efforts must be focussed on reversing the trend in water resources depletion by adopting efficient irrigation technologies. The prevalent irrigation methods are less efficient due to more water losses through leaching and evaporation. Micro irrigation can be an effective tool for improving water use efficiency. The study was carried out with an objective of improving the WUE in rice-wheat cropping system with four irrigation methods in wheat crop viz check basin, drip, sprinkler and drip+rainport and three irrigation systems in rice (check basin, drip and sprinkler) at Indian Institute of Wheat and Barley Research, Karnal during 2012-13 and 2013-14. Irrigation treatments significantly affected the grain yield of both the crops. The highest grain yield of wheat (5752 kg ha-1) was obtained in check basin irrigation during 2012-13 followed by drip+rainport (5614 kg ha-1). However, the WUE of check basin method was minimum (1.32 kg m-3). During 2013-14, highest yield was obtained in drip+rainport (5545 kg ha-1) followed by drip irrigation (5475 kg ha-1) with the WUE of 1.57 and 1.55 kg m-3 respectively. In rice, significant higher grain yield (4028 and 4683 kg ha-1) was recorded in drip followed by sprinkler irrigation. The study concludes the maximum WUE in wheat under drip+rainport treatment and in rice it was under drip irrigation treatment. [ABSTRACT FROM AUTHOR]

Tilletia indica Mitra, the causal agent of Karnal bunt of wheat (KB), is a quarantined disease of international importance whose pathogen shows high variability due to its heterothallic nature. Pathogenic variation was studied under artificially inoculated conditions on 13 wheat genotypes including bread and dicoccum wheat. This study used 34 T. indica isolates collected from 6 major wheat growing states in India (Rajasthan, Haryana, Punjab, Himachal Pradesh, Uttarakhand, and Uttar Pradesh). Mean coefficient of infection of the isolates ranged from 2.11% (KBR4) to 14.60% (KBH1). Among the 13 genotypes screened, only 1 genotype was found to be highly susceptible to infection. KBR1 and KBHP3 were the most virulent and least aggressive isolates and had coefficients of infection of 79.42% and 6.22%, respectively, on the susceptible variety HD 2009. Pathogenic variability test revealed the existence of 3 different aggressive groups among the 34 selected isolates on a set of host differentials. A total of 64 monosporidial (Ms) lines were developed from the isolates, which originated from 6 states, representing 19 locations in the North Western plains zone of India. Self-paired Ms lines revealed 2 mating alleles. A total of 15 mating alleles were postulated using 46 Ms lines. This study confirmed the heterothallic nature of T. indica and the existence of multiple alleles controlling pathogenicity. [ABSTRACT FROM AUTHOR]

Two wheat varieties, one highly resistant (HD29) and another susceptible (WH542) and their recombinant lines were taken for expression profiling of cystatins at three stages (WS1, WS2 and WS3) of the developing spikes. Different biochemical and immunological techniques like protease inhibitor assay, ELISA, DOT-BLOT immunoassay and SDS-PAGE analysis were employed to reveal the relationship of cystatin expression with stage dependent resistance (P<0.01). Interestingly, in all the genotypes cystatin expression was the highest at WS2 stage which is most susceptible to Karnal bunt (KB) pathogen. Expression was higher in the resistant recombinant inbred lines than in the susceptible ones (P<0.0001). Percent disease severity results were also in accordance with cystatin expression studies and thus suggesting a direct role of cystatins in providing resistance against KB. Based on the presence of potential component markers like cystatins which are involved in defence, identification of resistant wheat germplasms can prove to be an important strategy for successful KB management. [ABSTRACT FROM AUTHOR]

The article offers information on the 52nd Wheat and Barley Workers' Meeting organized by the All India Coordinated Wheat and Barley Improvement Project (AICW&BIP) of the Indian Council of Agricultural Research (ICAR), an organization, that was held in India in 2014. Topics discussed include increasing production and productivity of wheat and barley, wheat varieties, and progress of research in peninsular and southern hill zones.

The winter wheat gene pool which possesses huge diversity for various agronomic traits it can be exploited for widening the genetic base and improving the yield of spring wheat varieties. With a view to assess the variability for various yield contributing traits in winter wheat, an experiment was conducted at Directorate of Wheat Research Karnal, Haryana. Fifty exotic winter wheat germplasm collections were evaluated for various yield contributing traits like plant height, number of tillers meter-1, spike length and thousand grains weight in a paired row experiment. The results showed that large variability was present for all the agronomic traits studied. The plant height of the genotypes ranged from 56.4 to 155 cm, while the number of tillers meter-1 row length ranged from 67 to 305. The spike length of winter wheat genotypes varied from 7.2 to 16.4 cm. Thousand grains weight was in the range of 19.6 to 47.96 g. Plant height is very important yield trait in winter wheat. The genotypes EC 609403 and EC 609399 were found to be of dwarf stature. The winter wheat lines viz., EC 479376, EC 493712, EC 493709, EC 609395 and EC 609401 had more number of tillers meter-1 (>150). Longer spikes (>12 cm) were observed in EC 479375, EC 609410, EC 609405 and EC 609400 lines. EC 528127, EC 479378, EC 609410 showed high thousand grains weight (45 g). These promising lines have successfully been utilized in hybridization for transferring the desirable traits in the agronomic base of spring cultivars for the development of spring lines with high yield and resistance. [ABSTRACT FROM AUTHOR]

Tan spot, caused by the fungus Pyrenophora tritici-repentis, causes serious yield losses in wheat (Triticum aestivum) and many other grasses. Race 1 of the fungus, which produces the necrosis toxin Ptr ToxA and the chlorosis toxin Ptr ToxC, is the most prevalent race in the Great Plains of the United States. Wheat genotypes with useful levels of resistance to race 1 have been deployed, but this resistance reduces damage by only 50 to 75%. Therefore, new sources of resistance to P tritici-repentis are needed. Recombinant inbred lines developed from a cross between the Indian spring wheat cvs. WH542 (resistant) and HD29 (moderately susceptible) were evaluated for reaction to race 1 of the fungus. Composite interval mapping revealed quantitative trait loci (QTL) on the short arm of chromosome 3A explaining 23% of the phenotypic variation, and the long arm of chromosome 5B explaining 27% of the variation. Both resistance alleles were contributed by the WH542 parent. The QTL on 5BL is probably tsn1, which was described previously. The 3AS QTL (QTs.ksu-3AS) on 3AS is a novel QTL for resistance to P tritici-repentis race 1. The QTL region is located in the most distal bin of chromosome 3AS in a 2.2- centimorgan marker interval. Flanking markers Xbarc45 and Xbarc86 are suitable for marker-assisted selection for tan spot resistance. [ABSTRACT FROM AUTHOR]

Multi-environment wheat trials provide valuable information on the extent of genotype x environment interaction, the stability of genotypes and define and confirm agro-ecological regions through associations among sites. The All India Coordinated Crop Improvement Project on wheat evaluates candidates for release across the wheat growing regions of India. To facilitate this process the wheat area is divided into six agro-ecological zones; the northwestern plains zone (NWPZ), the northeastern plains zone (NEPZ), the central zone (CZ), the peninsular zone (PZ), the northern hills zone (NHZ) and the southern hills zone (SHZ). Factor analytic (FA) models were used to analyze the genotype x environment interaction for yield of 813 wheat genotypes evaluated at 136 locations across the six agro-ecological zones in 1307 individual advanced variety trials between 2008/09 and 2012/13. Genotype x environment interaction was firstly assessed separately within each of the six established agro-ecological zones. Key locations with a high genetic correlation with all other locations within each zone were identified. Predicted genetic values of important cultivars that were represented in a wider range of environments within each zone were estimated and highly stable genotypes were found. Genotype x environment interaction was subsequently assessed across agro-ecological zones. Only those environments where the models accounted for > 99% of the genetic variance were retained for further analysis and two smaller zones (NHZ and SHZ) with little or no genotype congruence with other agro-ecological zones were removed. Thus 476 genotypes from 488 environments were included in the analysis. Fifteen clusters of environments with similar patterns of adaptation were found. These clusters were then characterized based on zonal classification, sowing time, irrigation regime, latitude and year and three regions broadly representing the main wheat growing areas of India were identified. These regions represent a combination of the NWPZ and NEPZ defined by latitude, a central region that combines CZ locations with northern PZ locations and a southern region comprised of southern PZ sites. Further stratification of these zones was then possible based on sowing time and irrigation practice. One cluster of 29 environments had a high average genetic correlation (r = 0.75) with most other environments and production zones. These represent key locations where larger numbers of entries might be grown in future seasons as they are the best predictors of yield across cropping zones. [ABSTRACT FROM AUTHOR]

Both drought and heat stress are responsible for decline in wheat (Triticum aestivum L.) production in many regions of the world. Intergovernmental Panel on Climate Change (IPCC) has predicted increase in these areas. Development of heat and drought tolerant genotypes is on priority. Landraces are unexploited genetic resources for various agronomic traits contributing tolerance to abiotic stress. Twenty-five wheat genotypes were evaluated in irrigated timely, rainfed timely and irrigated late sown conditions for 2 yr using 10 agronomic traits for their response to drought and heat stress and four stress indices (stress susceptibility index, stress tolerance index, mean productivity, and stress tolerance) were calculated. Variability averaged over traits was highest under rainfed conditions. Grain yield, plant height, and productive tillers were more sensitive and test grain weight as tolerant under drought. Under heat stress grain yield, grain weight, test grain weight and phenological traits were more sensitive. Productive tillers and grain number per spike were identified as important selection parameters for drought and grain weight (per spike and test grain weight) as for heat tolerance. Genotypes IC 321987, IC 322005, IC 138852, IC 138870 adapted to stressed environments or genotypes CPAN 4079 and NEPAL 38 stable over all environments can be used for introgression of the stress tolerance in elite cultivars. [ABSTRACT FROM AUTHOR]