Browsing by Author "P.H. Zaidi"

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Genetic gains with rapid-cycle genomic selection for combined drought and waterlogging tolerance in tropical maize (Zea mays L.)
(John Wiley and Sons Inc, 2020) Reshmi R. Das; M.T. Vinayan; Manish B. Patel; Ramesh K. Phagna; S.B. Singh; J.P. Shahi; Akashi Sarma; N.S. Barua; Raman Babu; K. Seetharam; Juan A. Burgueño; P.H. Zaidi
Rapid cycle genomic selection (RC-GS) helps to shorten the breeding cycle and reduce the costs of phenotyping, thereby increasing genetic gains in terms of both cost and time. We implemented RC-GS on two multi-parent yellow synthetic (MYS) populations constituted by intermating ten elite lines involved in each population, including four each of drought and waterlogging tolerant donors and two commercial lines, with proven commercial value. Cycle 1 (C1) was constituted based on phenotypic selection and intermating of the top 5% of 500 S2 families derived from each MYS population, test-crossed and evaluated across moisture regimes. C1 was advanced to the next two cycles (C2 and C3) by intermating the top 5% selected individuals with high genomic estimated breeding values (GEBVs) for grain yield under drought and waterlogging stress. To estimate genetic gains, population bulks from each cycle were test-crossed and evaluated across locations under different moisture regimes. Results indicated that the realised genetic gain under drought stress was 0.110 t ha−1 yr−1 and 0.135 t ha−1 yr−1, respectively, for MYS-1 and MYS-2. The gain was less under waterlogging stress, where MYS-1 showed 0.038 t ha−1 yr−1 and MYS-2 reached 0.113 t ha−1 yr−1. Genomic selection for drought and waterlogging tolerance resulted in no yield penalty under optimal moisture conditions. The genetic diversity of the two populations did not change significantly after two cycles of GS, suggesting that RC-GS can be an effective breeding strategy to achieve high genetic gains without losing genetic diversity. © 2020 The Authors. The Plant Genome published by Wiley Periodicals, Inc. on behalf of Crop Science Society of America
Genome-wide association mapping in maize: status and prospects
(Springer Science and Business Media Deutschland GmbH, 2021) Kumari Shikha; J.P. Shahi; M.T. Vinayan; P.H. Zaidi; A.K. Singh; B. Sinha
Genome-wide association study (GWAS) provides a robust and potent tool to retrieve complex phenotypic traits back to their underlying genetics. Maize is an excellent crop for performing GWAS due to diverse genetic variability, rapid decay of linkage disequilibrium, availability of distinct sub-populations and abundant SNP information. The application of GWAS in maize has resulted in successful identification of thousands of genomic regions associated with many abiotic and biotic stresses. Many agronomic and quality traits of maize are severely affected by such stresses and, significantly affecting its growth and productivity. To improve productivity of maize crop in countries like India which contribute only 2% to the world’s total production in 2019–2020, it is essential to understand genetic complexity of underlying traits. Various DNA markers and trait associations have been revealed using conventional linkage mapping methods. However, it has achieved limited success in improving polygenic complex traits due to lower resolution of trait mapping. The present review explores the prospects of GWAS in improving yield, quality and stress tolerance in maize besides, strengths and challenges of using GWAS for molecular breeding and genomic selection. The information gathered will facilitate elucidation of genetic mechanisms of complex traits and improve efficiency of marker-assisted selection in maize breeding. © 2021, King Abdulaziz City for Science and Technology.
Genomic-regions associated with cold stress tolerance in Asia-adapted tropical maize germplasm
(Nature Research, 2023) Kumari Shikha; Vinayan Madhumal Thayil; J.P. Shahi; P.H. Zaidi; Kaliyamoorthy Seetharam; Sudha K Nair; Raju Singh; Garg Tosh; Ashok Singamsetti; Saurabh Singh; B. Sinha
Maize is gaining impetus in non-traditional and non-conventional seasons such as off-season, primarily due to higher demand and economic returns. Maize varieties directed for growing in the winter season of South Asia must have cold resilience as an important trait due to the low prevailing temperatures and frequent cold snaps observed during this season in most parts of the lowland tropics of Asia. The current study involved screening of a panel of advanced tropically adapted maize lines to cold stress during vegetative and flowering stage under field conditions. A suite of significant genomic loci (28) associated with grain yield along and agronomic traits such as flowering (15) and plant height (6) under cold stress environments. The haplotype regression revealed 6 significant haplotype blocks for grain yield under cold stress across the test environments. Haplotype blocks particularly on chromosomes 5 (bin5.07), 6 (bin6.02), and 9 (9.03) co-located to regions/bins that have been identified to contain candidate genes involved in membrane transport system that would provide essential tolerance to the plant. The regions on chromosome 1 (bin1.04), 2 (bin 2.07), 3 (bin 3.05–3.06), 5 (bin5.03), 8 (bin8.05–8.06) also harboured significant SNPs for the other agronomic traits. In addition, the study also looked at the plausibility of identifying tropically adapted maize lines from the working germplasm with cold resilience across growth stages and identified four lines that could be used as breeding starts in the tropical maize breeding pipelines. © 2023, The Author(s).
Genotype × environment interaction and selection of maize (Zea mays L.) hybrids across moisture regimes
(Elsevier B.V., 2021) Ashok Singamsetti; J.P. Shahi; P.H. Zaidi; K. Seetharam; M.T. Vinayan; Munnesh Kumar; Saurav Singla; Kumari Shikha; Kartik Madankar
Genotype × environment (GE) interaction effect is one of the major challenges in identifying cultivars with stable performance across environments and years. Objective of the present study was to identify maize hybrids with high and stable yields under different soil moisture regimes such as drought, waterlogged and well-watered conditions. The trials were carried out in subsequent winter (Rabi) and summer-rainy (Kharif) seasons of 2017 and 2018 totaling seven test environments at the two different locations of India viz, Banaras Hindu University, Varanasi and CIMMYT, Hyderabad. After observing substantial and statistically significant GE interaction for studied traits, the phenotypic stability of maize hybrids was analyzed by AMMI, GGE biplot and multi-trait stability index (MTSI) methods. The study emphasized on the significance of AMMI and GGE biplots in deciphering the GE interactions based on grain yield data. Estimation of stability indices, WAASB (Weighted Average of Absolute Scores from the singular value decomposition of the matrix of BLUPs) for the GE interaction effects and WAASBY (a combination of WAASB and yield) scores for identification of the best suitable genotypes with high stability and maximum yield potential was highlighted. The investigation delineated the applicability of MTSI that computed based on the genotype-ideotype distance considering the multiple variables. The methods studied were concordant in the identification of the promising maize hybrids with high mean performance and greater phenotypic stability across the different soil moisture conditions. © 2021 Elsevier B.V.
IDENTIFICATION OF WATERLOGGING STRESS TOLERANT MAIZE (ZEA MAYS L.) HYBRIDS USING DIFFERENT SELECTION INDICES
(Punjab Agricultural University, 2023) Ashok Singamsetti; J.P. Shahi; P.H. Zaidi; K. Seetharam; Munnesh Kumar
[No abstract available]
Investigation on genotype-by-environment interaction and stable maize (Zea mays L.) hybrids across soil moisture conditions
(Springer, 2021) Ashok Singamsetti; J.P. Shahi; P.H. Zaidi; K. Seetharam; Kartik Madankar; Munnesh Kumar
Maize production and productivity are challenged by multiple and co-occurring stresses that impact crop growth, development and consequently the yields. Maize crop is often exposed to a combination of drought and waterlogging stresses during the same or alternative growing seasons, therefore it became a major challenge to select promising cultivars that fit across varied soil moisture conditions. In this context, the present experiment was carried out to evaluate 75 maize hybrids under six environments with a combination of cropping season, location and soil moisture condition. The objective of the present investigation is to carry out simultaneous selection of ideal maize hybrids with better yield potential and stable across soil moisture regimes through additive main effects and multiplicative interaction (AMMI) analysis. The analysis of variance for mean grain yield across test environments showed significant variation for genotype-by-environment interaction (GEI), along with genotypes and environments that ensured stability analysis. Five maize hybrids viz., ZH161303, ZH161478, ZH161330, ZH161047 and ZH161068 were found promising hybrids with high stability and productivity across the soil moisture regimes including low, excess and optimal soil moisture environments. © 2021, Society for Plant Research.
Stress-resilient maize for climate-vulnerable ecologies in the Asian tropics
(Southern Cross Publishing, 2020) P.H. Zaidi; Thanh Nguyen; Dang N. Ha; Suriphat Thaitad; Salahuddin Ahmed; Muhammad Arshad; Keshav B. Koirala; Tirtha R. Rijal; Prakash H. Kuchanur; Ayyanagouda M. Patil; Shyam S. Mandal; Ramesh Kumar; S.B. Singh; Bhupender Kumar; J.P. Shahi; M.B. Patel; Murali K. Gumma; Kamal Pandey; Ramesh Chaurasia; Azizul Haque; K. Seetharam; Reshmi R. Das; M.T. Vinayan; Zerka Rashid; S.K. Nair; B.S. Vivek
Most parts of the Asian tropics are hotspots of climate change effects and associated weather variabilities. One of the major challenges with climate change is the uncertainty and inter-annual variability in weather conditions as crops are frequently exposed to different weather extremes within the same season. Therefore, agricultural research must strive to develop new crop varieties with inbuilt resilience towards variable weather conditions rather than merely tolerance to individual stresses in a specific situation and/or at a specific crop stage. C4 crops are known for their wider adaptation to range of climatic conditions. However, recent climatic trends and associated variabilities seem to be challenging the threshold limit of wider adaptability of even C4 crops like maize. In collaboration with national programs and private sector partners in the region, CIMMYT-Asia maize program initiated research for development (R4D) projects largely focusing on saving achievable yields across range of variable environments by incorporating reasonable levels of tolerance/resistance to major abiotic and biotic stresses without compromising on grain yields under optimal growing conditions. By integrating novel breeding tools like - genomics, double haploid (DH) technology, precision phenotyping and reducing genotype x environment interaction effects, a new generation of maize germplasm with multiple stress tolerance that can grow well across variable weather conditions were developed. The new maize germplasm were targeted for stress-prone environments where maize is invariability exposed to a range of sub-optimal growing conditions, such as drought, heat, waterlogging and various virulent diseases. The overarching goal of the stress-resilient maize program has been to achieve yield potential with a downside risk reduction. © 2020 Southern Cross Publishing.
Study on Applicability of Genotype × Yield × Trait (GYT) Biplots over Genotype × Trait (GT) Biplots in Selection of Maize Hybrids across Soil Moisture Regimes
(Agricultural Research Communication Centre, 2024) Ashok Singamsetti; J.P. Shahi; P.H. Zaidi; K. Seetharam
Background: A large area of the maize production in Indo-Gangetic plains of India exposes alternative and combination of prolonged drought spells and heavy rainfall situation due to uncertainty of monsoon patterns. In such context, breeding for maize hybrids with cross-tolerant to both low and excess soil moisture stresses remain the ultimate alternative. Methods: Evaluation of 75 maize hybrids planted at Banaras Hindu University, India during the subsequent Rabi and Kharif seasons of 2017 and 2018, respectively. The hybrids were evaluated for acquiring information on inter-trait associations among yield and yield-related traits under different soil moisture regimes. The trials were planted in alpha-lattice design and managed stress was imposed and data recorded. Result: As our investigation was the evident of weak correlations among the traits studied, genotype × trait (GT) biplots are not advisable to select/discard the genotypes under moisture stress conditions. The goodness of fit for GT biplots constructed under studied moisture conditions were almost poor because of fair to moderate correlations among the traits. To accomplish this problem of weak associations, genotype × yield × trait (GYT) technique was advisable to perform the precise selection of genotypes under studied environments. The investigation emphasized on accuracy and adequacy in implementing of GYT biplots for characterizing and selecting suitable hybrids. © (2024), (Agricultural Research Communication Centre). All rights reserved.