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Fulltext Genotype × Environment Interaction and Stability Analysis of Commercial Hybrid Grain Corn Genotypes in Different Environments

Adham A, Ghaffar MBA, Ikmal AM, Shamsudin NAA

Life (Basel), 2022 Nov 03;12(11).
PMID: 36362928 DOI: 10.3390/life12111773

The introduction of superior grain corn genotypes with high and stable yield (YLD) in most environments is important to increase local production and reduce dependency on imported grain corn. In this study, days to tasseling (DT), plant height, and YLD of 11 grain corn genotypes were observed in 10 environments to evaluate the effects of genotype (G), environment (E), and genotype by environment interactions (GEI) using GGE analysis and the stability of genotypes using stability parameters. In each location, grain corn genotypes were arranged in three replications using a randomized complete block design. An analysis of variance showed that all three traits were highly significant toward G and E factors, whereas GEI showed that only DT and YLD were highly significant. Genotype V14 produced the highest YLD of 10,354 kg/ha, followed by V4 (10,114 kg/ha) and V2 (9797.74 kg/ha). These three genotypes also dominated in seven out of 10 tested environments. With regard to stability ranking, genotype V4 was the most stable genotype, with a big gap difference between the second (V14) and third places (V2). Therefore, V14, V4, and V2 were the most promising genotypes because of their great YLD performance and most stable across tested environments, which can be recommended to farmers for high-scale planting.
Fulltext Pyramiding of drought yield QTLs into a high quality Malaysian rice cultivar MRQ74 improves yield under reproductive stage drought

Shamsudin NAA, Swamy BPM, Ratnam W, Sta Cruz MT, Sandhu N, Raman AK, et al.

Rice (N Y), 2016 Dec;9(1):21.
PMID: 27164982 DOI: 10.1186/s12284-016-0093-6

BACKGROUND: With the objective of improving the grain yield (GY) of the Malaysian high quality rice cultivar MRQ74 under reproductive stage drought stress (RS), three drought yield QTLs, viz. qDTY 2.2, qDTY 3.1 , and qDTY 12.1 were pyramided by marker assisted breeding (MAB). Foreground selection using QTL specific markers, recombinant selection using flanking markers, and background selections were performed in every generation. BC1F3 derived pyramided lines (PLs) with different combinations of qDTY 2.2, qDTY 3.1 , and qDTY 12.1 were evaluated under both RS and non-stress (NS) during the dry season (DS) of 2013 and 2014 at IRRI.
RESULTS: The GY reductions in RS trials compared to NS trials ranged from 79 to 99 %. Plant height (PH) was reduced and days to flowering (DTF) was delayed under RS. Eleven BC1F5 MRQ74 PLs with yield advantages of 1009 to 3473 kg ha(-1) under RS and with yields equivalent to MRQ74 under NS trials were identified as promising drought tolerance PLs. Five best PLs, IR 98010-126-708-1-4, IR 98010-126-708-1-3, IR 98010-126-708-1-5, IR 99616-44-94-1-1, and IR 99616-44-94-1-2 with a yield advantage of more than 1000 kg ha(-1) under RS and with yield potential equivalent to that of MRQ74 under NS were selected. The effect of three drought grain yield QTLs under RS in MRQ74 was validated. Under NS, PLs with two qDTY combinations (qDTY 2.2 + qDTY 12.1 ) performed better than PLs with other qDTY combinations, indicating the presence of a positive interaction between qDTY 2.2 and qDTY 12.1 in the MRQ74 background.
CONCLUSION: Drought tolerant MRQ74 PLs with a yield advantage of more than 1000 kg ha(-1) under RS were developed. Differential yield advantages of different combinations of the qDTYs indicate a differential synergistic relationship among qDTYs.
Fulltext Marker-assisted selection strategy to pyramid two or more QTLs for quantitative trait-grain yield under drought

Kumar A, Sandhu N, Dixit S, Yadav S, Swamy BPM, Shamsudin NAA

Rice (N Y), 2018 May 29;11(1):35.
PMID: 29845495 DOI: 10.1186/s12284-018-0227-0

BACKGROUND: Marker-assisted breeding will move forward from introgressing single/multiple genes governing a single trait to multiple genes governing multiple traits to combat emerging biotic and abiotic stresses related to climate change and to enhance rice productivity. MAS will need to address concerns about the population size needed to introgress together more than two genes/QTLs. In the present study, grain yield and genotypic data from different generations (F3 to F8) for five marker-assisted breeding programs were analyzed to understand the effectiveness of synergistic effect of phenotyping and genotyping in early generations on selection of better progenies.
RESULTS: Based on class analysis of the QTL combinations, the identified superior QTL classes in F3/BC1F3/BC2F3 generations with positive QTL x QTL and QTL x background interactions that were captured through phenotyping maintained its superiority in yield under non-stress (NS) and reproductive-stage drought stress (RS) across advanced generations in all five studies. The marker-assisted selection breeding strategy combining both genotyping and phenotyping in early generation significantly reduced the number of genotypes to be carried forward. The strategy presented in this study providing genotyping and phenotyping cost savings of 25-68% compared with the traditional marker-assisted selection approach. The QTL classes, Sub1 + qDTY 1.1 + qDTY 2.1 + qDTY 3.1 and Sub1 + qDTY 2.1 + qDTY 3.1 in Swarna-Sub1, Sub1 + qDTY 1.1 + qDTY 1.2 , Sub1 + qDTY 1.1 + qDTY 2.2 and Sub1 + qDTY 2.2 + qDTY 12.1 in IR64-Sub1, qDTY 2.2 + qDTY 4.1 in Samba Mahsuri, Sub1 + qDTY 3.1 + qDTY 6.1 + qDTY 6.2 and Sub1 + qDTY 6.1 + qDTY 6.2 in TDK1-Sub1 and qDTY 12.1 + qDTY 3.1 and qDTY 2.2 + qDTY 3.1 in MR219 had shown better and consistent performance under NS and RS across generations over other QTL classes.
CONCLUSION: "Deployment of this procedure will save time and resources and will allow breeders to focus and advance only germplasm with high probability of improved performance. The identification of superior QTL classes and capture of positive QTL x QTL and QTL x background interactions in early generation and their consistent performance in subsequent generations across five backgrounds supports the efficacy of a combined MAS breeding strategy".
Fulltext Association Mapping of Yield and Yield-related Traits Under Reproductive Stage Drought Stress in Rice (Oryza sativa L.)

Swamy BPM, Shamsudin NAA, Rahman SNA, Mauleon R, Ratnam W, Sta Cruz MT, et al.

Rice (N Y), 2017 Dec;10(1):21.
PMID: 28523639 DOI: 10.1186/s12284-017-0161-6

BACKGROUND: The identification and introgression of major-effect QTLs for grain yield under drought are some of the best and well-proven approaches for improving the drought tolerance of rice varieties. In the present study, we characterized Malaysian rice germplasm for yield and yield-related traits and identified significant trait marker associations by structured association mapping.
RESULTS: The drought screening was successful in screening germplasm with a yield reduction of up to 60% and heritability for grain yield under drought was up to 78%. There was a wider phenotypic and molecular diversity within the panel, indicating the suitability of the population for quantitative trait loci (QTL) mapping. Structure analyses clearly grouped the accessions into three subgroups with admixtures. Linkage disequilibrium (LD) analysis revealed that LD decreased with an increase in distance between marker pairs and the LD decay varied from 5-20 cM. The Mixed Linear model-based structured association mapping identified 80 marker trait associations (MTA) for grain yield (GY), plant height (PH) and days to flowering (DTF). Seven MTA were identified for GY under drought stress, four of these MTA were consistently identified in at least two of the three analyses. Most of these MTA identified were on chromosomes 2, 5, 10, 11 and 12, and their phenotypic variance (PV) varied from 5% to 19%. The in silico analysis of drought QTL regions revealed the association of several drought-responsive genes conferring drought tolerance. The major-effect QTLs are useful in marker-assisted QTL pyramiding to improve drought tolerance.
CONCLUSION: The results have clearly shown that structured association mapping is one of the feasible options to identify major-effect QTLs for drought tolerance-related traits in rice.
Data on genome resequencing of the rice cultivar MR219 and its abiotic stress tolerant mutant lines, NMR152 and NMR151

Ahmad F, Hasan N, Hisham SN, Yusof SN, Hassan AA, Hussein S, et al.

Data Brief, 2023 Feb;46:108815.
PMID: 36582993 DOI: 10.1016/j.dib.2022.108815

The genomics and genetic information of Malaysian rice (Oryza sativa L.) and their mutant lines are very limited. Therefore, the genome resequencing of two drought and submergence tolerant mutant rice lines, NMR152 and NMR151 and their parental line, MR219 was performed using Illumina Hi Seq 4000 platform with 20x sequencing coverage to facilitate the identification of causal mutations and the discovery of candidate variants of single nucleotide polymorphisms (SNPs) from their genome. The identification of SNPs would be useful in developing functional SNP markers related to drought and submergences resistance traits. Genome sequence data (FASTQ format) of the mutants and their parental line have been deposited into the National Center for Biotechnology Information (NCBI) database under sequence read archive (SRA) data with accessions SRR20824202 (NMR152), SRR20995190 (NMR151) and SRR21043964 (MR219), respectively.
Fulltext Genetic Loci Governing Grain Yield and Root Development under Variable Rice Cultivation Conditions

Catolos M, Sandhu N, Dixit S, Shamsudin NAA, Naredo MEB, McNally KL, et al.

Front Plant Sci, 2017;8:1763.
PMID: 29085383 DOI: 10.3389/fpls.2017.01763

Drought is the major abiotic stress to rice grain yield under unpredictable changing climatic scenarios. The widely grown, high yielding but drought susceptible rice varieties need to be improved by unraveling the genomic regions controlling traits enhancing drought tolerance. The present study was conducted with the aim to identify quantitative trait loci (QTLs) for grain yield and root development traits under irrigated non-stress and reproductive-stage drought stress in both lowland and upland situations. A mapping population consisting of 480 lines derived from a cross between Dular (drought-tolerant) and IR64-21 (drought susceptible) was used. QTL analysis revealed three major consistent-effect QTLs for grain yield (qDTY1.1, qDTY1.3 , and qDTY8.1 ) under non-stress and reproductive-stage drought stress conditions, and 2 QTLs for root traits (qRT9.1 for root-growth angle and qRT5.1 for multiple root traits, i.e., seedling-stage root length, root dry weight and crown root number). The genetic locus qDTY1.1 was identified as hotspot for grain yield and yield-related agronomic and root traits. The study identified significant positive correlations among numbers of crown roots and mesocotyl length at the seedling stage and root length and root dry weight at depth at later stages with grain yield and yield-related traits. Under reproductive stage drought stress, the grain yield advantage of the lines with QTLs ranged from 24.1 to 108.9% under upland and 3.0-22.7% under lowland conditions over the lines without QTLs. The lines with QTL combinations qDTY1.3 +qDTY8.1 showed the highest mean grain yield advantage followed by lines having qDTY1.1 +qDTY8.1 and qDTY1.1 +qDTY8.1 +qDTY1.3 , across upland/lowland reproductive-stage drought stress. The identified QTLs for root traits, mesocotyl length, grain yield and yield-related traits can be immediately deployed in marker-assisted breeding to develop drought tolerant high yielding rice varieties.