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Hyderabad, India

Jain A.,Barwale Foundation | Balaravi P.,Osmania University | Shenoy V.,Barwale Foundation
Biologia (Poland) | Year: 2013

The progress in development and dissemination of drought tolerant lines has been slow as compared to the increasing drought prevalence in the rice growing regions. Significant amount of work has been done in the past on drought resistance traits in rice crop, still the benefit of improved drought tolerant rice cultivars reaching the farmer's field is not very high and ways to expedite the development of drought tolerant and productive rice cultivars needs to be addressed. In this article, an assessment of easily practicable approach of managed stress screening and prospect of direct selection for yield under drought stress is discussed. Also the large effect yield QTLs identified for grain yield under drought stress field conditions is being reviewed for successful introgression into elite genetic background for developing drought tolerant cultivars with improved yield for the drought prone target environment. © 2013 Versita Warsaw and Springer-Verlag Wien. Source


Kalmeshwer Gouda P.,Barwale Foundation | Mohan Kumar Varma C.,Barwale Foundation | Saikumar S.,Barwale Foundation | Kiran B.,Barwale Foundation | And 2 more authors.
Crop Science | Year: 2012

Rice (Oryza sativa L.) is one of the important food crops drastically affected by drought. Considering the low heritability of grain yield under water stress, several secondary traits associated with drought tolerance have been used, but the success achieved in deriving cultivars with high yield potential under stress is less compared to irrigated conditions. Hence, objective of the experiment was to estimate heritability for grain yield under lowland stress and select for grain yield per se using wild species Oryza meridionalis Ng and also to identify physio-morphological traits responsible for withstanding water stress. A population derived from O. sativa cv. IR58025B × O. meridionalis (BC 2F 3) was evaluated under control and stress conditions. Variability observed for yield and component traits indicated O. meridionalis to be a good source of useful alleles for drought tolerance. Broad-sense heritability (h 2) of grain yield under stress, although only 33.1%, was comparable to control 59.4%, indicating direct selection for grain yield per se can be practiced. Twenty high-yielding selected lines and 40 random lines were evaluated under control and stress conditions to estimate selection response. Yield of selected lines outperformed random lines and checks under stress. Furthermore, 10 lines (5 high yielding and 5 low yielding) selected from the population were characterized for root morphological traits. Maximum root length (MRL) and root volume (RV) of selected high-yielding lines recorded maximum compared with checks and low-yielding lines indicating positive influence of drought avoidance root traits on grain yield under stress. Hence, O. meridionalis can be a good source of root traits contributing to stress tolerance and selection for grain yield under stress is an effective strategy in deriving drought tolerant lines in rice. © Crop Science Society of America. Source


Wade L.J.,Charles Sturt University | Bartolome V.,International Rice Research Institute | Mauleon R.,International Rice Research Institute | Vasant V.D.,Tamil Nadu Agricultural University | And 28 more authors.
PLoS ONE | Year: 2015

The rapid progress in rice genotyping must be matched by advances in phenotyping. A better understanding of genetic variation in rice for drought response, root traits, and practical methods for studying them are needed. In this study, the OryzaSNP set (20 diverse genotypes that have been genotyped for SNP markers) was phenotyped in a range of field and container studies to study the diversity of rice root growth and response to drought. Of the root traits measured across more than 20 root experiments, root dry weight showed the most stable genotypic performance across studies. The environment (E) component had the strongest effect on yield and root traits. We identified genomic regions correlated with root dry weight, percent deep roots, maximum root depth, and grain yield based on a correlation analysis with the phenotypes and aus, indica, or japonica introgression regions using the SNP data. Two genomic regions were identified as hot spots in which root traits and grain yield were co-located; on chromosome 1 (39.7-40.7 Mb) and on chromosome 8 (20.3-21.9 Mb). Across experiments, the soil type/ growth medium showed more correlations with plant growth than the container dimensions. Although the correlations among studies and genetic co-location of root traits from a range of study systems points to their potential utility to represent responses in field studies, the best correlations were observed when the two setups had some similar properties. Due to the co-location of the identified genomic regions (from introgression block analysis) with QTL for a number of previously reported root and drought traits, these regions are good candidates for detailed characterization to contribute to understanding rice improvement for response to drought. This study also highlights the utility of characterizing a small set of 20 genotypes for root growth, drought response, and related genomic regions. © 2015 Wade et al. Source


Saikumar S.,Barwale Foundation | Saikumar S.,Osmania University | Saikumar S.,Directorate of Rice Research | Kalmeshwer Gouda P.,Monsanto Corporation | And 5 more authors.
Field Crops Research | Year: 2014

Water stress is a major abiotic stress limiting the rice production and yield stability in rainfed conditions and getting worse with the predicted global climatic change. A Backcross inbred line (BIL) population derived from Swarna/WAB 450-I-B-P-157-2-1 was screened for grain yield under reproductive stage drought stress and irrigated conditions during DS2013, WS2012 and DS2012. A major qDTY3.2 with large and consistent effect on grain yield was mapped on chromosome 3 flanked by RM14303 and RM22 across three seasons under both stress and control conditions. qDTY3.2 explained a phenotypic variance of 29.5%, 18.8% and 31.8% under drought stress during DS13, WS12 and DS12, respectively. Apart from grain yield, qDTY3.2 is also account for variation in canopy temperature during flowering and seedling shoot dry weight and drought recovery under stress conditions. Lines with QTL showed a clear grain yield advantage over lines without QTL under both stress and control conditions. Due to the consistent effect of qDTY3.2 across diverse environments and varied level of stresses makes it an appropriate candidate for MAS. Introgression of such genomic regions in to elite drought susceptible backgrounds can lead to enhancement of grain yield level to a greater extent. © 2014 Elsevier B.V. Source


Khera P.,Barwale Foundation | Khera P.,Indian International Crops Research Institute for the Semi Arid Tropics | Singh A.K.,Barwale Foundation | Priyadarshi R.,Barwale Foundation | And 7 more authors.
Plant Genetic Resources: Characterisation and Utilisation | Year: 2015

To maximize heterosis, it is important to understand the genetic diversity of germplasm and associate useful phenotypic traits such as fertility restoration for hybrid rice breeding. The objectives of the present study were to characterize genetic diversity within a set of rice germplasm groups using coefficient of parentage (COP) values and 58 simple sequence repeat (SSR) markers for 124 genotypes having different attributes such as resistance/tolerance to various biotic and abiotic stresses. These lines were also used for identifying prospective restorers and maintainers for wild abortive-cytoplasmic male sterile (CMS) line. The mean COP value for all the lines was 0.11, indicating that the genotypes do not share common ancestry. The SSR analysis generated a total of 268 alleles with an average of 4.62 alleles per locus. The mean polymorphism information content value was 0.53, indicating that the markers selected were highly polymorphic. Grouping based on COP analysis revealed three major clusters pertaining to the indica, tropical japonica and japonica lines. A similar grouping pattern with some variation was also observed for the SSR markers. Fertility restoration phenotype based on the test cross of the 124 genotypes with a CMS line helped identify 23 maintainers, 58 restorers and 43 genotypes as either partial maintainers or partial restorers. This study demonstrates that COP analysis along with molecular marker analysis might encourage better organization of germplasm diversity and its use in hybrid rice breeding. Potential restorers identified in the study can be used for breeding high-yielding stress-tolerant medium-duration rice hybrids, while maintainers would prove useful for developing new rice CMS lines. © NIAB 2014. Source

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