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QTLs for tolerance of drought and breeding for tolerance of abiotic and biotic stress: an integrated approach.

Dixit S, Huang BE, Sta Cruz MT, Maturan PT, Ontoy JC, Kumar A - PLoS ONE (2014)

Bottom Line: This strategy allowed us to identify QTLs for GY along with rapid development of high-yielding purelines tolerant to blast and drought with considerably reduced efforts.Apart from this, it also allowed us to study the effects of the selection cycle for blast tolerance.With tolerance to two major stresses and high yield potential, these lines may provide yield stability in rainfed rice areas.

View Article: PubMed Central - PubMed

Affiliation: International Rice Research Institute (IRRI), Los Baños, Laguna, Philippines.

ABSTRACT

Background: The coupling of biotic and abiotic stresses leads to high yield losses in rainfed rice (Oryza sativa L.) growing areas. While several studies target these stresses independently, breeding strategies to combat multiple stresses seldom exist. This study reports an integrated strategy that combines QTL mapping and phenotypic selection to develop rice lines with high grain yield (GY) under drought stress and non-stress conditions, and tolerance of rice blast.

Methodology: A blast-tolerant BC2F3-derived population was developed from the cross of tropical japonica cultivar Moroberekan (blast- and drought-tolerant) and high-yielding indica variety Swarna (blast- and drought-susceptible) through phenotypic selection for blast tolerance at the BC2F2 generation. The population was studied for segregation distortion patterns and QTLs for GY under drought were identified along with study of epistatic interactions for the trait.

Results: Segregation distortion, in favour of Moroberekan, was observed at 50 of the 59 loci. Majority of these marker loci co-localized with known QTLs for blast tolerance or NBS-LRR disease resistance genes. Despite the presence of segregation distortion, high variation for DTF, PH and GY was observed and several QTLs were identified under drought stress and non-stress conditions for the three traits. Epistatic interactions were also detected for GY which explained a large proportion of phenotypic variance observed in the population.

Conclusions: This strategy allowed us to identify QTLs for GY along with rapid development of high-yielding purelines tolerant to blast and drought with considerably reduced efforts. Apart from this, it also allowed us to study the effects of the selection cycle for blast tolerance. The developed lines were screened at IRRI and in the target environment, and drought and blast tolerant lines with high yield were identified. With tolerance to two major stresses and high yield potential, these lines may provide yield stability in rainfed rice areas.

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Related in: MedlinePlus

Comparison of gene content of qDTY3.2 and qDTY11.1 based on percentage of genes belonging to seven gene classes within the two QTLs.
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pone-0109574-g006: Comparison of gene content of qDTY3.2 and qDTY11.1 based on percentage of genes belonging to seven gene classes within the two QTLs.

Mentions: Gene content of qDTY3.2andqDTY11.1 was classified into 7 classes and percentage of genes falling into each class was calculated (Fig 6.). A large proportion of the genes in bot QTLs were genes coding for known proteins other than those known to be directly related to stress response. Apart from this, large proportion of genes were also related to other expressed proteins in both QTLs. qDTY3.2 however showed a much higher percentage of genes related to enzyme synthesis and function while qDTY11.1 showed a much higher percentage of retrotransposon proteins as compared to qDTY3.2. 8% of the genes within qDTY3.2 6% of genes for qDTY11.1 were genes known to be directly associated to stress response or those which could be crucial for maintenance of plant function under stress. These included genes coding for heat shock proteins, no apical meristem proteins, membrane, cell cycle related proteins and zinc finger proteins (File S2). qDTY3.2 also showed the presence of flowering related genes such as AP2 domain containing proteins and MADS box family genes while qDTY11.1 showed the presence of a large number of nucleotide- binding site leucine- rich repeats (NBS-LRR) genes which are known to be major candidates for blast resistance.


QTLs for tolerance of drought and breeding for tolerance of abiotic and biotic stress: an integrated approach.

Dixit S, Huang BE, Sta Cruz MT, Maturan PT, Ontoy JC, Kumar A - PLoS ONE (2014)

Comparison of gene content of qDTY3.2 and qDTY11.1 based on percentage of genes belonging to seven gene classes within the two QTLs.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4196913&req=5

pone-0109574-g006: Comparison of gene content of qDTY3.2 and qDTY11.1 based on percentage of genes belonging to seven gene classes within the two QTLs.
Mentions: Gene content of qDTY3.2andqDTY11.1 was classified into 7 classes and percentage of genes falling into each class was calculated (Fig 6.). A large proportion of the genes in bot QTLs were genes coding for known proteins other than those known to be directly related to stress response. Apart from this, large proportion of genes were also related to other expressed proteins in both QTLs. qDTY3.2 however showed a much higher percentage of genes related to enzyme synthesis and function while qDTY11.1 showed a much higher percentage of retrotransposon proteins as compared to qDTY3.2. 8% of the genes within qDTY3.2 6% of genes for qDTY11.1 were genes known to be directly associated to stress response or those which could be crucial for maintenance of plant function under stress. These included genes coding for heat shock proteins, no apical meristem proteins, membrane, cell cycle related proteins and zinc finger proteins (File S2). qDTY3.2 also showed the presence of flowering related genes such as AP2 domain containing proteins and MADS box family genes while qDTY11.1 showed the presence of a large number of nucleotide- binding site leucine- rich repeats (NBS-LRR) genes which are known to be major candidates for blast resistance.

Bottom Line: This strategy allowed us to identify QTLs for GY along with rapid development of high-yielding purelines tolerant to blast and drought with considerably reduced efforts.Apart from this, it also allowed us to study the effects of the selection cycle for blast tolerance.With tolerance to two major stresses and high yield potential, these lines may provide yield stability in rainfed rice areas.

View Article: PubMed Central - PubMed

Affiliation: International Rice Research Institute (IRRI), Los Baños, Laguna, Philippines.

ABSTRACT

Background: The coupling of biotic and abiotic stresses leads to high yield losses in rainfed rice (Oryza sativa L.) growing areas. While several studies target these stresses independently, breeding strategies to combat multiple stresses seldom exist. This study reports an integrated strategy that combines QTL mapping and phenotypic selection to develop rice lines with high grain yield (GY) under drought stress and non-stress conditions, and tolerance of rice blast.

Methodology: A blast-tolerant BC2F3-derived population was developed from the cross of tropical japonica cultivar Moroberekan (blast- and drought-tolerant) and high-yielding indica variety Swarna (blast- and drought-susceptible) through phenotypic selection for blast tolerance at the BC2F2 generation. The population was studied for segregation distortion patterns and QTLs for GY under drought were identified along with study of epistatic interactions for the trait.

Results: Segregation distortion, in favour of Moroberekan, was observed at 50 of the 59 loci. Majority of these marker loci co-localized with known QTLs for blast tolerance or NBS-LRR disease resistance genes. Despite the presence of segregation distortion, high variation for DTF, PH and GY was observed and several QTLs were identified under drought stress and non-stress conditions for the three traits. Epistatic interactions were also detected for GY which explained a large proportion of phenotypic variance observed in the population.

Conclusions: This strategy allowed us to identify QTLs for GY along with rapid development of high-yielding purelines tolerant to blast and drought with considerably reduced efforts. Apart from this, it also allowed us to study the effects of the selection cycle for blast tolerance. The developed lines were screened at IRRI and in the target environment, and drought and blast tolerant lines with high yield were identified. With tolerance to two major stresses and high yield potential, these lines may provide yield stability in rainfed rice areas.

Show MeSH
Related in: MedlinePlus