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Carbon Isotope Discrimination: Potential for Indirect Selection for Seed Yield in Canola

Matus, Alejandro, Slinkard, Alfred, van Kessel, Chris
Crop science 1995 v.35 no.5 pp. 1267-1271
Brassica napus, crop yield, seeds, genetic improvement, genetic variation, carbon, stable isotopes, water use efficiency, genotype-environment interaction, heritability, genotype, Saskatchewan
Carbon isotope discrimination (CID) has been proposed as a parameter to select indirectly for improved water use efficiency and seed yield. To determine the effectiveness of CID to select indirectly for seed yield, 10 diverse canola (L.) genotypes were grown at five locations in Saskatchewan in 1992 and 1993. Samples were collected for CID determination from leaves at flowering, mature stems, and mature seed. Phenotypic correlations between seed yield and the three CID traits were not significant. Genotypic differences in CID were significant, but were caused by ‘AC Tristar’ canola, which is triazine tolerant and has a low photosynthetic capacity. The ranking of canola genotypes for CID was constant across locations and years. The CID of mature seeds was significantly lower than CID of leaves at flowering or CID of mature stems. The correlation between dry matter at flowering (DMF) and CID of leaves at flowering was negative and significant, but inconsistent across locations and years. The broad sense heritability () for seed yield was similar to that for CID traits. These results suggest that CID would not be effective for indirectly selecting for improved seed yield in canola.