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Agronomic assessment of the wheat semi-dwarfing gene Rht8 in contrasting nitrogen treatments and water regimes.

Kowalski AM, Gooding M, Ferrante A, Slafer GA, Orford S, Gasperini D, Griffiths S - Field Crops Res. (2016)

Bottom Line: The yield penalty associated with the Rht8 introgression was overcome at low N and in irrigated conditions in the UK, and in the high-temperature site in Spain.Decreased spike length and constant spikelet number in the Rht8 NIL resulted in spike compaction of 15%, independent of N and water regime.Further genetic dissection of these loci is required.

View Article: PubMed Central - PubMed

Affiliation: John Innes Centre, Norwich Research Park, Colney Ln, Norwich NR4 7UH, UK.

ABSTRACT

Reduced height 8 (Rht8) is the main alternative to the GA-insensitive Rht alleles in hot and dry environments where it reduces plant height without yield penalty. The potential of Rht8 in northern-European wheat breeding remains unclear, since the close linkage with the photoperiod-insensitive allele Ppd-D1a is unfavourable in the relatively cool summers. In the present study, two near-isogenic lines (NILs) contrasting for the Rht8/tall allele from Mara in a UK-adapted and photoperiod-sensitive wheat variety were evaluated in trials with varying nitrogen fertiliser (N) treatments and water regimes across sites in the UK and Spain. The Rht8 introgression was associated with a robust height reduction of 11% regardless of N treatment and water regime and the Rht8 NIL was more resistant to root-lodging at agronomically-relevant N levels than the tall NIL. In the UK with reduced solar radiation over the growing season than the site in Spain, the Rht8 NIL showed a 10% yield penalty at standard agronomic N levels due to concomitant reduction in grain number and spike number whereas grain weight and harvest index were not significantly different to the tall NIL. The yield penalty associated with the Rht8 introgression was overcome at low N and in irrigated conditions in the UK, and in the high-temperature site in Spain. Decreased spike length and constant spikelet number in the Rht8 NIL resulted in spike compaction of 15%, independent of N and water regime. The genetic interval of Rht8 overlaps with the compactum gene on 2DS, raising the possibility of the same causative gene. Further genetic dissection of these loci is required.

No MeSH data available.


Related in: MedlinePlus

Yield, grain number and spike number in the Rht8 NIL, tall NIL and Paragon in Reading and Lleida. These data are the mean values ± SEM (standard error of the mean). Nitrogen treatment was N1 (40 kg N ha−1), N2 (100 kg N ha−1) and N3 (200 kg N ha−1).
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fig0020: Yield, grain number and spike number in the Rht8 NIL, tall NIL and Paragon in Reading and Lleida. These data are the mean values ± SEM (standard error of the mean). Nitrogen treatment was N1 (40 kg N ha−1), N2 (100 kg N ha−1) and N3 (200 kg N ha−1).

Mentions: In standard UK agronomic conditions (rainfed and high N (N3, 200 kg N ha−1)), the Rht8 NIL conferred a mean yield penalty of −8% across environments, ranging from −4 to −26% relative to the tall NIL (Supplementary Table 3). Exceptions to the yield penalty in the UK were in non-standard agronomic conditions at lower N treatments and in irrigated conditions. In Reading, the yield penalty was overcome at the lowest N input (N1) (Fig. 4a), whereas in Norwich the yield penalty was not observed at N1 or N2 (Supplementary Table 3). Irrigation treatments were conducted in the 2013 and 2014 growing seasons in Norwich. At 200 kg N ha−1 (N3), the yield penalty associated with the Rht8 introgression in rainfed conditions was eradicated by providing irrigation. This result was observed across both years (Supplementary Table 3). At N1, irrigation increased yield proportionally across all genotypes so that the yield penalty in the Rht8 NIL was maintained.


Agronomic assessment of the wheat semi-dwarfing gene Rht8 in contrasting nitrogen treatments and water regimes.

Kowalski AM, Gooding M, Ferrante A, Slafer GA, Orford S, Gasperini D, Griffiths S - Field Crops Res. (2016)

Yield, grain number and spike number in the Rht8 NIL, tall NIL and Paragon in Reading and Lleida. These data are the mean values ± SEM (standard error of the mean). Nitrogen treatment was N1 (40 kg N ha−1), N2 (100 kg N ha−1) and N3 (200 kg N ha−1).
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4862442&req=5

fig0020: Yield, grain number and spike number in the Rht8 NIL, tall NIL and Paragon in Reading and Lleida. These data are the mean values ± SEM (standard error of the mean). Nitrogen treatment was N1 (40 kg N ha−1), N2 (100 kg N ha−1) and N3 (200 kg N ha−1).
Mentions: In standard UK agronomic conditions (rainfed and high N (N3, 200 kg N ha−1)), the Rht8 NIL conferred a mean yield penalty of −8% across environments, ranging from −4 to −26% relative to the tall NIL (Supplementary Table 3). Exceptions to the yield penalty in the UK were in non-standard agronomic conditions at lower N treatments and in irrigated conditions. In Reading, the yield penalty was overcome at the lowest N input (N1) (Fig. 4a), whereas in Norwich the yield penalty was not observed at N1 or N2 (Supplementary Table 3). Irrigation treatments were conducted in the 2013 and 2014 growing seasons in Norwich. At 200 kg N ha−1 (N3), the yield penalty associated with the Rht8 introgression in rainfed conditions was eradicated by providing irrigation. This result was observed across both years (Supplementary Table 3). At N1, irrigation increased yield proportionally across all genotypes so that the yield penalty in the Rht8 NIL was maintained.

Bottom Line: The yield penalty associated with the Rht8 introgression was overcome at low N and in irrigated conditions in the UK, and in the high-temperature site in Spain.Decreased spike length and constant spikelet number in the Rht8 NIL resulted in spike compaction of 15%, independent of N and water regime.Further genetic dissection of these loci is required.

View Article: PubMed Central - PubMed

Affiliation: John Innes Centre, Norwich Research Park, Colney Ln, Norwich NR4 7UH, UK.

ABSTRACT

Reduced height 8 (Rht8) is the main alternative to the GA-insensitive Rht alleles in hot and dry environments where it reduces plant height without yield penalty. The potential of Rht8 in northern-European wheat breeding remains unclear, since the close linkage with the photoperiod-insensitive allele Ppd-D1a is unfavourable in the relatively cool summers. In the present study, two near-isogenic lines (NILs) contrasting for the Rht8/tall allele from Mara in a UK-adapted and photoperiod-sensitive wheat variety were evaluated in trials with varying nitrogen fertiliser (N) treatments and water regimes across sites in the UK and Spain. The Rht8 introgression was associated with a robust height reduction of 11% regardless of N treatment and water regime and the Rht8 NIL was more resistant to root-lodging at agronomically-relevant N levels than the tall NIL. In the UK with reduced solar radiation over the growing season than the site in Spain, the Rht8 NIL showed a 10% yield penalty at standard agronomic N levels due to concomitant reduction in grain number and spike number whereas grain weight and harvest index were not significantly different to the tall NIL. The yield penalty associated with the Rht8 introgression was overcome at low N and in irrigated conditions in the UK, and in the high-temperature site in Spain. Decreased spike length and constant spikelet number in the Rht8 NIL resulted in spike compaction of 15%, independent of N and water regime. The genetic interval of Rht8 overlaps with the compactum gene on 2DS, raising the possibility of the same causative gene. Further genetic dissection of these loci is required.

No MeSH data available.


Related in: MedlinePlus