Variation in chlorophyll A content and stability in wheat flag leaves

Boyd, W.J.R.; Walker, M.G.

Variation in chlorophyll A content and stability in wheat flag leaves

1972

Boyd, W.J.R. | Walker, M.G.

Chlorophyll a content in segments of flag leaves from 19 wheat varieties excised at ear emergence was shown to vary by a factor of 2.3. Chlorophyll stability (expressed as the percentage of chlorophyll remaining in the segments after 4 days senescence in moist boxes at 20 °C in the dark) varied by a factor of 8.5. Variation in these parameters between varieties appeared to be independent. Five of these varieties, representing the extremes, were further tested at three nutrient levels, and under three light/temperature regimes. Whilst lower leaf canopy senescence was greater at low nutrient levels, flag leaf chlorophyll content actually increased slightly, stability remaining fairly constant. In contrast, as light intensity improved, chlorophyll content increased markedly, with a consequent slight non-significant decrease in stability. Testing the F1 progeny of a partial diallel involving four of the above varieties showed that the mean chlorophyll content, and stability, of the parents followed the same ranking as the progeny to which they contributed. This suggests heritable control of the parameters measured. Some implications of these results in breeding for resistance to senescence are discussed.

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