Carbon Isotope Discrimination, Leaf Ash Content and Grain Yield in Bread and Durum Wheat Grown under Full-Irrigated Conditions

The relationships between ash content, carbon isotope discrimination and yield were studied in durum wheat (Triticum durum Desf.) grown in a Mediterranean region (north-western Syria) under three different water regimes (hereafter referred to as environments). Ash content (on dry mass basis) was measured in the flag leaf about 3 weeks after anthesis (leaf ash) and in mature kernels (kernel ash), whereas Δ was analysed in the penultimate leaf at heading (leaf Δ) and in mature kernels (kernel Δ). Leaf Δ was weakly or not related with the other parameters. Leaf ash correlated positively with kernel Δ (P≤0.001), even in the driest environment, which gave a mean yield of 1.5 t ha-1. For the four parameters, correlations with yield remained significant (P≤0.001) after correcting for days to heading. All the parameters showed a higher broad-sense heritability than yield. The parameter that showed the best genetic correlation with grain yield was kernel ash (r2= 0.88), followed by kernel Δ (r2 = 0.69) and leaf ash (r2 = 0.64), whereas leaf Δ (r2 = 0.26) was the least correlated parameter. Except for kernel ash, these parameters always correlated positively with grain yield. The negative relationships of kernel ash (on dry mass basis) with yield and all the other parameters may be attributable to the finding that kernel ash was higher in those genotypes more affected by drought during grain filling. Thus, kernel ash was negatively related (P≤0.001) with total kernel mass per spike. Prediction of grain yield through multiple linear regression suggests that kernel ash can be used as complementary criterion to either kernel Δ or leaf ash.

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Relationship of grain yield with carbon isotope discrimination and ash content in lines derived from a bread wheat cultivar

The Journal of Agricultural Science ◽

10.1017/s0021859605005356 ◽

2005 ◽

Vol 143 (4) ◽

pp. 275-282 ◽

Cited By ~ 7

Author(s):

J. T. TSIALTAS ◽

I. S. TOKATLIDIS ◽

E. TAMOUTSIDIS ◽

I. XYNIAS

Keyword(s):

Grain Yield ◽

Carbon Isotope ◽

Bread Wheat ◽

Carbon Isotope Discrimination ◽

Selection Criterion ◽

Ash Content ◽

Individual Plant ◽

Low Density ◽

Isotope Discrimination ◽

Relationship Of

The objective was to explore, in lines derived from a bread wheat (Triticum aestivum L.) cultivar, the association of grain yield with carbon isotope discrimination (Δ) and ash content (Ash) determined in both flag leaf and kernel. Divergent selection within the cv. Nestos, based on individual plant yield under very low density (11547 plants/ha), produced 20 lines. Progeny evaluation was conducted in two sites of Northern Hellas (Greece) at both low (11547 plants/ha) and high (5000000 plants/ha) density. The results showed significant differences between lines for grain yield, Δ and Ash. However, only the conclusions on grain yield were similar in low and high density, perhaps because the selection criterion under low density was grain yield. This, combined with the lack of any strong relationship of grain yield with either Δ or Ash, failed to confirm the usefulness of these physiological traits as indirect selection criteria, when the within-cultivar variation for grain yield is exploited. The possible association of grain yield with Δ and Ash appeared to be influenced by various factors such as drought, level of grain yield and altitude. Results also showed that less plant-to-plant variability, as expressed by the coefficients of variation (CV) of single-plant yields, was associated with decreased drought response and higher yield stability. The less stressed lines were those that used water more conservatively till anthesis and maintained a high photosynthetic rate during grain filling.

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