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The effects of dwarfing genes on seedling root growth of wheat.

Wojciechowski T, Gooding MJ, Ramsay L, Gregory PJ - J. Exp. Bot. (2009)

Bottom Line: Most modern wheat cultivars contain major dwarfing genes, but their effects on root growth are unclear.No significant differences in root length were found between semi-dwarfing lines and the control lines in any experiment, nor was there a significant difference between the root lengths of the two cultivars grown in the field.A direct effect of dwarfing alleles on root growth during seedling establishment, rather than a secondary partitioning effect, was suggested by the present experiments.

View Article: PubMed Central - PubMed

Affiliation: SCRI, Invergowrie, Dundee DD2 5DA, UK. dario.prada@pioneer.com

ABSTRACT
Most modern wheat cultivars contain major dwarfing genes, but their effects on root growth are unclear. Near-isogenic lines (NILs) containing Rht-B1b, Rht-D1b, Rht-B1c, Rht8c, Rht-D1c, and Rht12 were used to characterize the effects of semi-dwarfing and dwarfing alleles on root growth of 'Mercia' and 'Maris Widgeon' wheat cultivars. Wheat seedlings were grown in gel chambers, soil-filled columns, and in the field. Roots were extracted and length and dry mass measured. No significant differences in root length were found between semi-dwarfing lines and the control lines in any experiment, nor was there a significant difference between the root lengths of the two cultivars grown in the field. Total root length of the dwarf lines (Rht-B1c, Rht-D1c, and Rht12) was significantly different from that of the control although the effect was dependent on the experimental methodology; in gel chambers root length of dwarfing lines was increased by approximately 40% while in both soil media it was decreased (by 24-33%). Root dry mass was 22-30% of the total dry mass in the soil-filled column and field experiments. Root length increased proportionally with grain mass, which varied between NILs, so grain mass was a covariate for the analysis of variance. Although total root length was altered by dwarf lines, root architecture (average root diameter, lateral root:total root ratio) was not affected by reduced height alleles. A direct effect of dwarfing alleles on root growth during seedling establishment, rather than a secondary partitioning effect, was suggested by the present experiments.

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Effects of Rht NILs on total root length. (A) Total root length of NILs grown in gel chambers after 10 d (the bar is ±1 SED: lsd 5%=7.90 cm per plant). (B) Total root length of plants grown in soil-filled columns after 26 d (the bar is ±1 SED: lsd 5% = 441.4 cm per plant). (C) Effects of Rht NILs on total root length of field-grown plants. NILs of two wheat cultivars (tall cultivar cv. Maris Widgeon and cv. Mercia) were measured after 30 d (the bar is ±1 SED: lsd 5%=9.02 cm per plant).
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fig3: Effects of Rht NILs on total root length. (A) Total root length of NILs grown in gel chambers after 10 d (the bar is ±1 SED: lsd 5%=7.90 cm per plant). (B) Total root length of plants grown in soil-filled columns after 26 d (the bar is ±1 SED: lsd 5% = 441.4 cm per plant). (C) Effects of Rht NILs on total root length of field-grown plants. NILs of two wheat cultivars (tall cultivar cv. Maris Widgeon and cv. Mercia) were measured after 30 d (the bar is ±1 SED: lsd 5%=9.02 cm per plant).

Mentions: In the gel chamber experiment, total root length (Fig. 2) of the dwarf lines (Rht-B1c, Rht-D1c, and Rht12) was significantly increased compared with the control and semi-dwarf lines over time. The NILs with a dwarf genotype had a significantly increased total root length compared with the control at day 4 (Rht12, P=0.04) and day 8 (Rht-B1c and Rht-D1c, P=0.02). Mean total root length adjusted for the covariate of the control was 30.1 cm (Fig. 3a), while that of the dwarf genotypes was significantly increased (P=0.02) by 40% (Rht-B1c), 29% (Rht-D1c), and 48% (Rht12) at day 10 of the experiment. In contrast to the gel chamber experiment, total root length was significantly reduced in the dwarf lines compared with the control in both the soil column and field experiments. In the soil-filled column experiment, total root length of the dwarf lines was significantly [P= 0.035, least significant difference (lsd) 5%=446.3 cm per plant] decreased by 29% (Rht-B1c), 33% (Rht-D1c), and 24% (Rht12) compared with the control (mean control: 1932 cm) and semi-dwarfing lines (Rht-B1b, 1691 cm; Rht-D1b, 1775 cm; and Rht8c, 1852 cm) (Fig. 3b). Similarly in the field experiment (Fig. 3c), the dwarf lines of both backgrounds had significantly (P <0.001, lsd 5%=10.04 cm per plant) shorter total root length compared with the controls (Mercia, 53.3 cm and Maris Widgeon, 54.6 cm): [Mercia Rht-B1c (–25%), Mercia Rht-D1c (–29%), and Mercia Rht12 (–24%); and Maris Widgeon Rht-B1c (–29%)]. However, there were no significant differences between the semi-dwarfing lines (Mercia Rht-B1b, 53.3 cm; Mercia Rht-D1b, 51.3 cm; Mercia Rht8c, 51.1 cm; and Maris Widgeon Rht-B1b, 55.5 cm) and the control line in any of the experiments, nor was there a significant difference between the total root lengths of the two cultivars grown in the field.


The effects of dwarfing genes on seedling root growth of wheat.

Wojciechowski T, Gooding MJ, Ramsay L, Gregory PJ - J. Exp. Bot. (2009)

Effects of Rht NILs on total root length. (A) Total root length of NILs grown in gel chambers after 10 d (the bar is ±1 SED: lsd 5%=7.90 cm per plant). (B) Total root length of plants grown in soil-filled columns after 26 d (the bar is ±1 SED: lsd 5% = 441.4 cm per plant). (C) Effects of Rht NILs on total root length of field-grown plants. NILs of two wheat cultivars (tall cultivar cv. Maris Widgeon and cv. Mercia) were measured after 30 d (the bar is ±1 SED: lsd 5%=9.02 cm per plant).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
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fig3: Effects of Rht NILs on total root length. (A) Total root length of NILs grown in gel chambers after 10 d (the bar is ±1 SED: lsd 5%=7.90 cm per plant). (B) Total root length of plants grown in soil-filled columns after 26 d (the bar is ±1 SED: lsd 5% = 441.4 cm per plant). (C) Effects of Rht NILs on total root length of field-grown plants. NILs of two wheat cultivars (tall cultivar cv. Maris Widgeon and cv. Mercia) were measured after 30 d (the bar is ±1 SED: lsd 5%=9.02 cm per plant).
Mentions: In the gel chamber experiment, total root length (Fig. 2) of the dwarf lines (Rht-B1c, Rht-D1c, and Rht12) was significantly increased compared with the control and semi-dwarf lines over time. The NILs with a dwarf genotype had a significantly increased total root length compared with the control at day 4 (Rht12, P=0.04) and day 8 (Rht-B1c and Rht-D1c, P=0.02). Mean total root length adjusted for the covariate of the control was 30.1 cm (Fig. 3a), while that of the dwarf genotypes was significantly increased (P=0.02) by 40% (Rht-B1c), 29% (Rht-D1c), and 48% (Rht12) at day 10 of the experiment. In contrast to the gel chamber experiment, total root length was significantly reduced in the dwarf lines compared with the control in both the soil column and field experiments. In the soil-filled column experiment, total root length of the dwarf lines was significantly [P= 0.035, least significant difference (lsd) 5%=446.3 cm per plant] decreased by 29% (Rht-B1c), 33% (Rht-D1c), and 24% (Rht12) compared with the control (mean control: 1932 cm) and semi-dwarfing lines (Rht-B1b, 1691 cm; Rht-D1b, 1775 cm; and Rht8c, 1852 cm) (Fig. 3b). Similarly in the field experiment (Fig. 3c), the dwarf lines of both backgrounds had significantly (P <0.001, lsd 5%=10.04 cm per plant) shorter total root length compared with the controls (Mercia, 53.3 cm and Maris Widgeon, 54.6 cm): [Mercia Rht-B1c (–25%), Mercia Rht-D1c (–29%), and Mercia Rht12 (–24%); and Maris Widgeon Rht-B1c (–29%)]. However, there were no significant differences between the semi-dwarfing lines (Mercia Rht-B1b, 53.3 cm; Mercia Rht-D1b, 51.3 cm; Mercia Rht8c, 51.1 cm; and Maris Widgeon Rht-B1b, 55.5 cm) and the control line in any of the experiments, nor was there a significant difference between the total root lengths of the two cultivars grown in the field.

Bottom Line: Most modern wheat cultivars contain major dwarfing genes, but their effects on root growth are unclear.No significant differences in root length were found between semi-dwarfing lines and the control lines in any experiment, nor was there a significant difference between the root lengths of the two cultivars grown in the field.A direct effect of dwarfing alleles on root growth during seedling establishment, rather than a secondary partitioning effect, was suggested by the present experiments.

View Article: PubMed Central - PubMed

Affiliation: SCRI, Invergowrie, Dundee DD2 5DA, UK. dario.prada@pioneer.com

ABSTRACT
Most modern wheat cultivars contain major dwarfing genes, but their effects on root growth are unclear. Near-isogenic lines (NILs) containing Rht-B1b, Rht-D1b, Rht-B1c, Rht8c, Rht-D1c, and Rht12 were used to characterize the effects of semi-dwarfing and dwarfing alleles on root growth of 'Mercia' and 'Maris Widgeon' wheat cultivars. Wheat seedlings were grown in gel chambers, soil-filled columns, and in the field. Roots were extracted and length and dry mass measured. No significant differences in root length were found between semi-dwarfing lines and the control lines in any experiment, nor was there a significant difference between the root lengths of the two cultivars grown in the field. Total root length of the dwarf lines (Rht-B1c, Rht-D1c, and Rht12) was significantly different from that of the control although the effect was dependent on the experimental methodology; in gel chambers root length of dwarfing lines was increased by approximately 40% while in both soil media it was decreased (by 24-33%). Root dry mass was 22-30% of the total dry mass in the soil-filled column and field experiments. Root length increased proportionally with grain mass, which varied between NILs, so grain mass was a covariate for the analysis of variance. Although total root length was altered by dwarf lines, root architecture (average root diameter, lateral root:total root ratio) was not affected by reduced height alleles. A direct effect of dwarfing alleles on root growth during seedling establishment, rather than a secondary partitioning effect, was suggested by the present experiments.

Show MeSH
Related in: MedlinePlus