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Ram S.,Directorate of Wheat Research
Journal of Plant Biochemistry and Biotechnology | Year: 2012

Serpins (Serine proteinase inhibitors) are the family of proteins involved in the inhibition of proteinases from endogenous and other sources and thus have role in disease and pest resistance. In addition, serpins have the properties influencing grain quality traits. The genes coding for serpin proteins are present on the long arm of the 5B chromosome. In the present investigation, allelic variations in the serpin genes encoded by Srp5Bb were assessed using CAP-PCR among the 300 wheat varieties developed in India during the last 100 years. Eighty percent of the varieties exhibited wild type (Srp5Ba) and 20% mutated (Srp5Bb) form of the allele. Moreover, the frequency of Srp5Bb allele decreased among the recently released varieties as compared to older varieties. Only six out of 50 varieties used as checks in national trials showed the presence of Srp5Bb allele. There was no relationship between Srp5B allelic types and grain hardness. The information is useful to further investigate the role of Srp5B alleles in disease resistance and imparting grain quality. © 2011 Society for Plant Biochemistry and Biotechnology.

Mohan D.,Directorate of Wheat Research
Indian Journal of Genetics and Plant Breeding | Year: 2014

Six long-term wheat cultivars of India were examined for the period 1993-2012 to observe climate induced variations in productivity and growth pattern. Each cultivar represented a particular environment manifested by a specific agro-climatic region and production condition, productivity of which was derived from 6-10 fixed locations. Significant yield fluctuations in majority of the environments indicated that climatic conditions were changing in different parts of the country. Trend in yield change appeared cyclic and site differences also turned larger in certain situations. Pattern of climate induced yield variations depended upon region and production condition as the extent was high in late-sown wheats in comparison to timely-sown and less in the Indo-Gangetic plains in comparison to central-peninsular India. Disparity occurred within Indo-Gangetic plains also, as yield fluctuated more in the eastern region. Direction of change varied in different environments as yield decelerated in late-sown wheats of Indo-Gangetic plains and enhanced in harsh climate of central-peninsular India. Crop growth during vegetative phase turned favourable in central-peninsular India whereas reduction in grain ripening period was evident in northeastern plains. Linear trends and magnitude of variations in yield cum component traits were applied to demarcate differences in varietal response. Level of climate resilience differed in the study material and two cultivars namely HUW 234 and LOK 1 appeared climate resilient. © 2014, Indian Society of Genetics and Plant Breeding. All rights reserved.

Yu L.-X.,Cornell University | Morgounov A.,International Maize and Wheat Improvement Center | Wanyera R.,Kenya Agricultural Research Institute | Keser M.,International Maize and Wheat Improvement Center | And 2 more authors.
Theoretical and Applied Genetics | Year: 2012

The evolution of a new race of stem rust, generally referred to as Ug99, threatens global wheat production because it can overcome widely deployed resistance genes that had been effective for many years. To identify loci conferring resistance to Ug99 in wheat, a genome-wide association study was conducted using 232 winter wheat breeding lines from the International Winter Wheat Improvement Program. Breeding lines were genotyped with diversity array technology, simple sequence repeat and sequence-tagged site markers, and phenotyped at the adult plant stage for resistance to stem rust in the stem rust resistance screening nursery at Njoro, Kenya during 2009-2011. A mixed linear model was used for detecting marker-trait associations. Twelve loci associated with Ug99 resistance were identified including markers linked to known genes Sr2 and Lr34. Other markers were located in the chromosome regions where no Sr genes have been previously reported, including one each on chromosomes 1A, 2B, 4A and 7B, two on chromosome 5B and four on chromosome 6B. The same data were used for investigating epistatic interactions between markers with or without main effects. The marker csSr2 linked to Sr2 interacted with wPt4930 on 6BS and wPt729773 in an unknown location. Another marker, csLV34 linked to Lr34, also interacted with wPt4930 on 6BS and wPt4916 on 2BS. The frequent involvement of wPt4916 on 2BS and wPt4930 on 6BS in interactions with other significant loci on the same or different chromosomes suggested complex genetic control for adult plant resistance to Ug99 in winter wheat germplasm. © 2012 Springer-Verlag.

Mohan D.,Directorate of Wheat Research | Gupta R.K.,Directorate of Wheat Research
Indian Journal of Genetics and Plant Breeding | Year: 2013

Contribution of 16 grain parameters was examined in endproduct quality of 60 Indian bread wheat cultivars equally representing three production conditions and five megazones of the country. Even though several grain properties were correlated with product quality, only 5-6 contributed significantly. High sedimentation volume and good grain appearance were essential in the domestic product like chapati but contribution of gluten content and test weight was negative. Low polyphenol oxidase activity and less bran content emerged as strong indicators of good chapati making. Positive contributors in bread quality of Indian wheats were gluten content, gluten index, GLU 1 score and test weight whereas good grain appearance was a hindrance. Since Indian wheats are generally hard textured, grain hardness index was not a limiting factor in defining quality standards of bread and chapati. Variability available in sedimentation volume could cater needs of chapati but it could not emerge as significant contributor in bread making as cultivars with high value are rare in India. Grain softness was the dominating trait in biscuit spread factor but this product did not require high gluten content and the physical grain superiority. Study illustrated that just three parameters i.e. high sedimentation volume, gluten index and GLU 1 score in bread; and low test weight, gluten content and grain hardness index in biscuit account for 71- 72% variations in the baked products and can be used as selection criteria under Indian conditions.

Wasson A.P.,CSIRO | Richards R.A.,CSIRO | Chatrath R.,Directorate of Wheat Research | Misra S.C.,Agharkar Research Institute | And 5 more authors.
Journal of Experimental Botany | Year: 2012

Wheat yields globally will depend increasingly on good management to conserve rainfall and new varieties that use water efficiently for grain production. Here we propose an approach for developing new varieties to make better use of deep stored water. We focus on water-limited wheat production in the summer-dominant rainfall regions of India and Australia, but the approach is generally applicable to other environments and root-based constraints. Use of stored deep water is valuable because it is more predictable than variable in-season rainfall and can be measured prior to sowing. Further, this moisture is converted into grain with twice the efficiently of in-season rainfall since it is taken up later in crop growth during the grain-filling period when the roots reach deeper layers. We propose that wheat varieties with a deeper root system, a redistribution of branch root density from the surface to depth, and with greater radial hydraulic conductivity at depth would have higher yields in rainfed systems where crops rely on deep water for grain fill. Developing selection systems for mature root system traits is challenging as there are limited high-throughput phenotyping methods for roots in the field, and there is a risk that traits selected in the lab on young plants will not translate into mature root system traits in the field. We give an example of a breeding programme that combines laboratory and field phenotyping with proof of concept evaluation of the trait at the beginning of the selection programme. This would greatly enhance confidence in a high-throughput laboratory or field screen, and avoid investment in screens without yield value. This approach requires careful selection of field sites and years that allow expression of deep roots and increased yield. It also requires careful selection and crossing of germplasm to allow comparison of root expression among genotypes that are similar for other traits, especially flowering time and disease and toxicity resistances. Such a programme with field and laboratory evaluation at the outset will speed up delivery of varieties with improved root systems for higher yield. © 2012 The Author.

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